Jun 102016
 

First of all, we would like to thank everyone that took part in our survey. There were one or two dissenting voices and, sadly, one person descended into a personal attack on one of the survey’s authors; nevertheless, in general, the reception was positive.
Just to clear up one or two points raised:
We are sorry that not all the answers in the multiple choice questions suited everyone – occasionally choices have to be made when setting questions and, as anyone who has taken part either in professional psychological tests or simple online quizzes will confirm, at times we are given to choose from something not entirely appropriate to our own situation. We could possibly have given an “other” option a little more often…
A few people felt the questions to be biased. The questions were reviewed by equine professionals, amateurs and even the veterinary profession and we have made a concerted effort to avoid bias; the personal opinions of those involved in the survey should have no place in the actual results. One source of confusion over this matter may be the fact that questions were “streamed”; where there was an either/or choice, subsequent questions would relate to the principal answer. However, the questions remained essentially the same (for example, someone who used a bit was asked why, someone who didn’t was asked why not). Again, maybe some explanation at the start of the survey might have been better.
The results are not intended to reflect what is good nor what is bad: we are not seeking to divide opinion nor to take any side in an argument with this survey; we simply want to present a picture of the current welfare situation of the horse. Remember, welfare is not the same for everyone: one considers stabling essential, another an abomination, one considers barefoot to be the right choice, another finds shoes a necessity. Whatever the personal perception, we have tried to portray the variety of ways horses’ welfare is approached without being judgemental.
Although the survey has been posted within differing disciplines, the actual demographics are a little more complicated. Just which discipline stables more or shoes less, who feeds what and when, these things are neither represented nor asked in the survey. This alone prevents jumping to conclusions about who might be “better” for their horse – a question that, as has already been stated, is not being posed.

So, what are the initial results?

Stabling:

  • a larger number of respondents indicated that they keep their horses out 24/7 with only 1/5 stabling their horses; from reactions to the questionnaire, it is probable that a number of owners responded with 24/7 since they do not stable all year around.
  • of those stabling, nearly 90% stable at night, although more than a third of these said they reverse the situation at certain times of the year, keeping their horses in during the day and turning out at night.
  • only one person said they always turn out at night.
  • more than 10 % of respondents said their horses are never turned out.

Turnout:
of those horses stabled

  • a small majority has between 6 and 12 hours turnout
  • a little under ⅓ of stabled horses being turned out for up to 18 hours
  • just under 10% are turned out for somewhere up to 6 hours a day
  • only one horse is shown as spending more than 18 hours a day on turnout
  • as already recorded, more than 10% are never turned out

for all horses, stabled and not stabled – but, of course, not including those not turned out:

  • just 5% are segregated in their own paddock or field; the reasoning was not specifically questioned
  • a very small majority is turned out with one or two other horses
  • more than 40% is turned out in a larger group – these two last groups account for over 90% of the horses represented
  • 5 horses have the company of other animals including donkeys, cattle, chickens, goats, sheep and dogs – although two are apparently also in the company of a different sort of horse!

Feeding:

  • nearly ⅔ of horses has unrestricted access to grass, slightly more than those with unrestricted access to hay (57%)
  • more than 20% of owners restricts access to grass whereas just over 10% restricts hay access
  • about 6% of owners allow their horses brief grazing with slightly fewer not allowing any grazing
  • between 4% and 5% of owners each fed hay once, thrice or four times a day with a very small majority in this group that feeds twice a day
  • more than 5% of owners never feeds hay

grains/cereals:

  • just two horses are fed grains/cereals ad lib – the authors are not sure whether this is actually the case, or whether the answer was misunderstood.
  • 17% feeds their horses restricted grains/cereals – this could possibly be categorised with the following:
  • over 40% feed once or twice a day – the numbers being divided almost equally
  • a large number but by no means a majority (38%) never feeds grains/cereals

supplements:

  • nearly ⅔ of owners gives their horse supplements, of these
  • ⅔ give once a day and ⅓ twice (just 1 and 2 people respectively give 4 and 3 times a day)
  • the supplements given vary widely although often they appear to be of a “general” nature. Very few owners indicate that they use specific makes. Magnesium and turmeric (curcuma) feature fairly regularly, as does vitamin E – only one instance is given of giving vitamin C. Other fairly specific mentions worth noting are biotin, zinc and copper and selenium. Although nobody specifically recorded iron, there was one owner that gave seaweed.

salt/mineral licks:

  • 4/5 of owners give their horses access to a salt lick – a third of these also offer a mineral lick
  • the remaining 1/5 give a mineral lick alone.

Activities:

  • Few people seem to take part in competition with any regularity, harness racing being almost completely absent!
  • A slightly larger group rides in harness recreationally but by far the most popular activity is recreational outdoor riding over short distances
  • Freestyling is fairly evenly spread among the occasionals, sometimes’ and the mostlies – although, when considering other demographics, a slightly surprising 35% never practices freestyle

frequency:

  • More than a third of respondents is active more than 16 hours a week with just under 40% active between 8 and 16 hours
  • Just 7½% fall into the category of less than 4 hours.

Feet:

The singling out any group within this survey was never the intention and probably nowhere is more prone to the pointing finger than within the sphere of the horse’s hoof. For this reason, although the figures are extant from the point of channeling the questions, the actual split shod/unshod is not discussed.

the shod horse:

  • a fairly even split – more than 60% total – indicated that their horse would go lame or his feet would wear down too fast without shoes
  • just over 10% felt their horse needed them for competition despite it not being a requirement, with less than 5% citing competitions that do require shoes
  • a fraction under 9% cites poor/crumbly/split hooves as the reason for needing to shoe
  • nearly 18% had been advised by a professional to apply orthopædic shoes – more than 10% being the vet
  • a small number cited comfort as a reason for shoeing; arthritis and acute laminitis being others

the unshod horse:

  • less than 5o% has always been barefoot
  • more than ¾ believe shoes to be damaging to the horse
  • over 12% cite the restricted amount or absence of riding as a reason for not shoeing
  • maybe surprisingly more farriers advised barefoot than vets but the total number of cases was appreciably smaller than advice to shoe.
  • transition experiences varied, some took a long time, others were almost instant. In general, 6 months seems to be a normal period
  • more than 60% considered using hoof boots of which nearly 20% ended up not
  • the overwhelming majority cite the reason for boots as being difficulty on stony or rocky terrain with ¼ citing transition difficulties.
  • nearly 25% has stopped using boots; 50% still use them but only on difficult/long rides.

Bits:

The use, or not, of bits was fairly even – a tiny majority choosing bitless over a bit.
Most people seemed to prefer the bit for the control they experienced, but this was also the general reason given by those who didn’t bit ! Several people expressed a desire to go bitless but said they hadn’t (yet) got the confidence. Nearly 60% of those who used a bit, said that they also rode bitless. The most used bit was the snaffle or a derivation thereof while the most used bitless setup was the sidepull.

Finally, 97% of people said that the horse weaned naturally from its mother between 6 and 24 months with a small majority indicating 6 – 12 months.
Although a clear majority, well over three-quarters, said the horse was fully grown at between 5 and 8 years – with 3 – 5 and 8 – 15 each taking a 10% share –  nearly 40% considers a horse capable of being ridden at between 3 and 5 years with 55% choosing 5 – 8. Just two people felt 6 – 12 and 12 – 24 months to be possible.

Over 47% considered a horse to be old at between 22 and 27 years with just over 30% placing the old horse between 27 and 35. Just 6% placed the old horse above 35 years, considerably less than the 15% that felt the 15 – 22 year old was old; although only two people put the age at 8 – 15.
These figures tend to correlate with the perceived average age at which a horse dies, 36% saying 22 – 27 and 33% saying 27 – 35. The latter seems to be something of a limit – just 11 people thought the average age of death to be over 35. It was rather disheartening to see how many people chose a lower age, well over ¼ putting it at under 22.

Most people again placed the life expectancy of the horse in the 27 – 35 bracket although now a third went for the 35 – 42 age range. Just over 5% considered it to be over 42 – nobody placed it below 15. This last was surprising since 1% felt the longevity to be in this bracket. In general, it appears that respondents felt longevity to be one bracket higher than life expectancy although 12.5% put it above 50.

Responses were received from, in no specific order, Australia, Belgium, Canada, France, Germany, Hungary, The Netherlands, Norway, Portugal, South Africa, Spain, Tanzania, UK, USA

 

We would like to thank everyone that has taken part; the survey is still open and will remain so until the last week of June and the final – full – analysis should be available by mid September.

Jun 092013
 

There must be something in the air at the moment; I was recently expounding the virtues of delaying a horse’s training under the saddle only to come across an article last week on The Horse website talking about (race)horse performance at 2, 3 and 5 years related to lesions.

The cause was at that moment of little interest, the age of the horses was. Should we be riding at such immature ages?

Despite being worlds apart, the racehorse industry and the home-hack do have one main thing in common, the wish to turn their beautiful horse into a beautiful rideable horse as soon as possible. After all, most of us don’t just want to look at our horse…

There is plenty of motivation to start early too. In dressage, there is a minimum age at which a horse may compete; according to FEI regulations for international dressage competition, it is six years but for many national events, the rules are different with the minimum age being as low as three. And when one considers horse-racing, the ages are even lower – the racing of two-year-olds is quite commonplace which requires them to be saddled up for the first time when they are not much older than 1½.

For the professional trainer and owner, it is all a question of money. Often the horse is – or can become – quite valuable. Keeping a horse costs money (ironically, for the owners of such horses, it is often just a fraction of their earnings) and the natural desire is to see the horse earn its keep as soon as possible. And eventually, a racehorse can be put out to stud and earn yet more that way – these days not even needing to attain a respectable age with the ability to freeze sperm – but the health of the horse is never the greatest consideration.

So what about the mere mortals of this world? Most horse owners will agree that a horse should not be ridden until it is about 4 years old. A respectable age, one could say; the horse is obviously no longer a foal and is more likely to grow outwards than upwards. However, the growth plates are still a long way off being closed. The last plates will close somewhere between 5½ and eight years old – and it is specifically these growth plates that are found in the back of the horse – all 32 of them!

Most growth plates lie across the weight bearing plane – think of knees, ankles, shoulders etc. – and are less affected by the carriage of weight. But the growth plates in the back lie parallel to the weight bearing plane whereby the back is easily streched and thus can suffer under the weight of the rider.

skeleton of the horseTo clarify, this is the order and the approximate age at which the growth plates close up:

1. Birth: distal phalanx (coffin bone)

2. Birth and six months: middle phalanx

3. Between six months and 1 year: proximal phalanx

4. Between 8 months and 1½ years: metacarpals/metatarsals (cannon bones)

5. Between 1½ and 2½ years: carpal bones

6. Between 2 and 2½ years: radius-ulna

7. Between 2½ and 3 years: ulna/femur, section that carries weight above the radius; tibia

8. Between 3 and 3½ years: humerus; bottom part of the femur

9. Between 3 and 4 years: pelvis begins to close, beginning with the extremities of the ischium, ilium and sacrum

10. Between 3½ and 4 years: lower part (that carries weight) of the scapula (shoulderblade)

; top neck vertebrae

12. From 4 years: tarsal bones then the growth plates between fibula and tibia (not without reason that 18th century literature forbade ploughing, crossing of deep mud and jumping for young horses)

13. Between 5½ and 8 years: vertebrae (the larger the horse and the longer the neck, the longer it takes for the growth plates to close up. For stallions, add another six months: this means a “warmblood” horse of about 17hh will not be fully grown until 8 years old.)

Of course, all this does not mean that we cannot do anything with our horses until they are eight, but it should certainly set us thinking about our training schemes.

For the professional horseworld, time is loss – except the economics are not taken into account. Maybe not so interesting for the racehorse owner – his horse is often little more than a money factory – but certainly for the livery and riding school owners. In much of Europe, the average age of a riding school horse is horrifically low and the general life-expectancy shows no correlation with what a horse should (healthily) be able to reach. Based upon the size of the animal and the size and rate of its heart etc., the horse has a potential life-expectancy of 50 years. Realistically a little lower at around 40 to 43 years. But a horrific number of horses has already been written off by the age of 20 – imagine writing off people when they get to 38 or 40…

Take a look at the table below – and decide for yourself which of the two columns fits your way of thinking best:

Begin training 3 years 7 years
Full potential 7 years 10 years
End “useful” life 18 years 35 years
Total work period 15 years? 25 years

Just by delaying the moment we start to ride by just 3 years, we can win 10 years in “useful” life. It makes you think…

 

Growth plate information: Timing and rate of skeletal maturation in horses, Dr Deb Bennett, 2005
“Useful Life” table: based on observations by Pierre Enoff, bio-mechanical engineer
Original article published in Dutch: http://www.kobolt.nl/gezondheid/leeftijd-bij-inrijden/   https://sabots-libres.eu/site/engagement/2013/leeftijd-bij-inrijden/

Jun 042013
 

Saff223May07.........Clicker training is one of the recent success stories of equestrianism. It makes use of a bridging signal to indicate the moment of the desired behaviour, followed by positive reinforcement. We are told that training with positive reinforcement is more ethical than training with negative reinforcement and/or punishment. We are told that positive reinforcement activates the pleasure circuits of the brain, releasing dopamine in a way totally distinct from the regions activated by techniques involving pressure and release. As clicker trainers we are adept at handling the various erroneous criticisms by sceptics – that horses in the wild do not use positive reinforcement, that hand-fed horses will be encouraged to bite, that understanding behavioural science predisposes us to being unfeeling scientists who can’t work with practical behaviour. We have horses who appear to engage in their training enthusiastically, sometimes they even don’t want us to end the session. It is just one long string of clicks and treats for us!

So what’s the problem?

Firstly there is the perception that clicker training can only be positive. We are giving a horse treats which is better than him having no treats. Therefore it is good. This is a somewhat simplistic view. Skinnerian stimulus-response chains do not take into account anything about the horse’s lifestyle and environment. In fact, Skinner seemed even to deny that they were relevant. If a horse pulls faces when you put his saddle on then you can clicker train him to make a happy face instead. If a horse won’t stand still in his stable you can target train him to stand motionless while you do things to him. You can train him to adopt dressage postures. You can train him to move at gaits that would require more advanced training if taught conventionally. You can train him not to respond to all manner of scary objects. You can even train him to lie down, permit you to lie down with him and take a great photo for your website. And so much more….

The trouble is that none of these training situations take into account the underlying reasons for the behaviour. The poorly-fitting saddle may be causing pain. The stabled horse may feel worried about a neighbouring horse. He may not have the right musculature to adopt the requested positions or perform advanced movements. He may learn to tolerate the scary objects but what if his fear of them is still greater than the pleasure of the treats? And lying down is all very well if he wants to do it but what about when the ground is hard or there is something in the vicinity which means he’d really rather not?

But horses wouldn’t do it if they didn’t want to?

This is the age-old question. It has been (and is) said of race-horses, show-jumpers, riding school horses, horses trained with natural horsemanship techniques and even the original process of domestication approximately six thousand years ago. Of course, these forms of horsemanship all include aversive stimuli, both physical and emotional, which provide some level of threat to the horse – “choose to do as I say, or else”. So the horse complies, apparently willingly, and the aversive stimulus can remain invisible to all but the most perceptive observer.

Clicker training is different because we are providing something pleasurable for the horse. We are absolved from guilt. Or are we? Domesticated horses have had a lifetime of complying with our wishes and they continue to do so when we pick up a clicker. The rules may have changed and we may be permitting the horse to offer a behaviour before confirming that it is the correct behaviour, but it is still the human who decides whether it is the correct behaviour. We want the horse to choose to offer behaviour spontaneously but it has to be the “right behaviour” – such mixed messages bestow a lot of emotional pressure on an animal who has previously been so well-conditioned to do as intstructed. It is like having “creative thinking” or “independent learning” timetabled at school (as indeed occurs these days), as though autonomy can be switched on and off. Good trainers who understand how to use variable schedules of reinforcement are then able to extract more and more behaviour out of the horse in return for the reward. This “Brave New World” of horse training can often be so blind to what the horse would really choose.

And then we have repetition. Just in case the horse is in any doubt as to who is calling the shots, some trainers seem to feel the need to train a behaviour over and over again. There seems to come a point where any pleasure circuitry triggered in the brain by the treats is more than compensated for by the conflict behaviours seen in the horse – the frustration and aggression, the sexual over-arousal, the boredom, the conditioned suppression, the worry. And the reason for this repetition is typically the perceived need for the horse to respond “less emotionally” or more “cleanly”. So our goal has become something coming dangerously close to the shut down automatons of some of the more aversive training methods we have tried to leave behind. What is going on?

The trouble with clicker training is that it is incredibly powerful. The trouble with horses is that the majority are very compliant because they wish to avoid conflict. It is very easy to evolve inadvertently from a novice clicker trainer, who wants to help her horse become more enthusiastic and have a more enriched life, to a more advanced clicker trainer who is looking for perfection and control and has rather forgotten why she started clicker training in the first place. I have never met anyone who actively clicker trains her horse because it is such a good way of exerting her authority. Yet that is so often how it has become. That desire to become a better and more achieving trainer just cannot help getting in the way of what is important to the horse. Yes, with clicker in one hand and treats in the other, we can become over-controlling, aversive stimuli who are actively, albeit inadvertently, working towards reduction of our horses’ autonomy and, hence, welfare.

And we haven’t even begun to talk about combining clicker training with negative reinforcement and punishment – that was the subject of a previous article so I shall spare you that this time…..

So what do I like about it?

Despite all these concerns, I really do rate clicker training very highly and would love to see it taken up by more people. Positive reinforcement (with or without a clicker) allows us to interact with horses in a way to which no other training method even comes close. But in order to tap into this wealth of potential, we really need to change our focus. We need to start again and look at what attracted us to clicker training in the first place.

When starting clicker training we tend to offer a neutral target; either through natural curiosity or by accident the horse touches it. He hears a click and receives a reward. After a few repetitions we see that incredible “light-bulb moment” as the horse works out what is happening. The horse realises that he can turn the human into a vending machine – it is the moment of a surge of self-confidence, empowerment and autonomy. As horse-loving owners/trainers we are hooked from this moment onwards. It is why we wanted to clicker train, we liked seeing our horses so happy and expressive. We liked the moment of being able to read our horses’ minds. I like clicker training when we stay in this place, when we don’t move out into the world of training behaviours just because we can, or over-training, or worrying about excessive stimulus control or trying constantly to deal with so-called behavioural problems.

When engaged in a simple free-shaping session, such as this, we are conveying a very powerful message to the horse. We are saying that he can choose to participate or not (even better if the session is in the field so grass is always available as an alternative to training). We are saying that he can earn rewards or opt not to earn rewards and nothing bad will happen, whichever option he chooses. We are saying that we will respect the decisions he makes, rather than trying to find alternative ways of obtaining compliance. The horse choosing to say “no” is not a slur on our training or on our relationship. It can be a sign that he is in good psychological health and feels sufficiently secure in his relationship with the owner that he can say “no”. After previous years of being conditioned to do as he is told, learning that he can opt to do or not to do something is incredibly liberating. When we turn clicker training into something bordering on authoritarian, we lose the most enlightened element of it – the opportunity to reinstate the horse’s autonomy. This is where clicker training has advantages in its ability to increase welfare; any technique using pressure and release cannot increase a sense of autonomy.

Despite being a strong advocate of positive reinforcement, often to the point of being misquoted as attempting a route of pure positive reinforcement, I have come to believe that autonomy is perhaps the most beneficial gift we can incorporate into our training. When positive reinforcement training is controlling and manipulative it erodes autonomy and diminishes the value of the rewards – it becomes a poisoned cue in itself. Horses have evolved to make many decisions for themselves – the erroneous idea that the majority of horses just blindly follow a leader is outdated – and there is no reason for this to have changed over the relatively brief period of domestication. Yet the vast majority of domesticated horses have no say in what they do when, are fed a prescribed diet at specific times and have no choice as to their companions. Indeed, the manner in which most horses are managed is contrary to even the most basic ethological time-budgets.

I do not pretend to use positive reinforcement all the time, but I reserve it for when I want to encourage my horse’s autonomy, alongside careful consideration of his evolutionary needs. I will use discrete and well-defined free-shaping sessions to reinforce the message that I will listen to my horse’s opinions. This is not to say that I will never over-ride my horse’s opinions because sometimes I do – afterall, none of us has autonomy 24/7 – but within a free-shaping session it is all his choice. The balance needs to be found where the horse has the self-confidence and trust in the owner that he can offer opinions confidently without feeling “shut down” if the opinions are over-ruled. I don’t use clicker training to train away problems or to train behaviours I actually care about training. I use clicker training to build a sufficiently strong relationship from which I can later use mild negative reinforcement when I feel it is appropriate. Obviously it depends very much on the horse as to how much of a balance must be struck between the need for free-shaping sessions and the appropriateness of incorporating mild pressure. In the early days of working with a new horse it may be that every interaction needs to be the horse’s decision. The long-term shaping plan will include being able to cope with direction from the human.

Free shaping allows the horse to behave in the most open and honest way, rather than just trying to avoid pressure whichever way he can. It is a means of communication, two-way communication as opposed to formal training. As a result, we are provided with the closest insight as to how a horse might be thinking. We can use this information to improve the life of the horse – we can learn about his learning style, what he likes and dislikes, how he values things, what he feels scared about. We can apply this information to any form of equestrianism in which we wish to participate – not to exploit and manipulate but to add value and reduce conflict.

I strongly believe that this approach to horsemanship is analogous to some of the methods used in human psychotherapy, most notably, the person-centred style of therapy pioneered by Carl Rogers (e.g. On Becoming a Person). There is also a beautiful description of such therapy applied to a six year old boy, thought to be mentally deficient but given the opportunity to develop a positive relationship with play therapist, Virgina Axline, and transform into the highly intelligent and advanced boy he was (Dibs: In Search of Self). This book shows the power of free-shaping in action and is remarkable for so many reasons, not least because the therapy took place for only one hour a week with the boy returned to a fairly aversive home life in between. Rogers believed that a therapeutic relationship hinged on three key factors – empathic understanding, genuineness and unconditional positive regard. While his earlier work studied the relationship between therapist and client, he later extended it to just about all relationships. I see no reason why this should not apply to horse-human relationships as well. Working with a troubled horse requires these same three attributes – an understanding of how that horse might be feeling, the patience to allow that horse to behave how he needs to behave without trying to manipulate or creating an agenda and respect and appreciation for every try that the horse makes. I think it’s fair to say that no equestrian discipline has these core points at the heart of the horse-human relationship. Yet…..

Catherine Bell is an equine behaviourist and independent barefoot trimmer with website http://www.equinemindandbody.co.uk and Facebook page http://www.facebook.com/ThinkingHorsemanshipForum

Jul 012012
 

Welcome to my round up of some of the latest releases in equine science. These scientific equine papers have provided some interesting information sure to spark debate and inform our equine management and training practises; including a most important paper which provides evidence that horses ridden in hyperflexion may experience difficulty breathing because of airway obstruction.

Factors in Horse Training

Does learning performance in horses relate to fearfulness, baseline stress hormone, and social rank?

By Janne Winther, Line Christensen Peerstrup Ahrendt, Randi Lintrup, Charlotte Gaillard, Rupert Palme, Jens Malmkvist

“The ability of horses to learn and remember new tasks is fundamentally important for their use by humans. Fearfulness may, however, interfere with learning, because stimuli in the environment can overshadow signals from the rider or handler. In addition, prolonged high levels of stress hormones can affect neurons within the hippocampus; a brain region central to learning and memory. In a series of experiments, we aimed to investigate the link between performance in two learning tests, the baseline level of stress hormones, measured as faecal cortisol metabolites (FCM), fearfulness, and social rank. Twenty-five geldings (2 or 3 years old) pastured in one group were included in the study. The learning tests were performed by professional trainers and included a number of predefined stages during which the horses were gradually trained to perform exercises, using either negative (NR) or positive reinforcement (PR). Each of the learning tests lasted 3 days; 7min/horse/day. The NR test was repeated in a novel environment. Performance, measured as final stage in the training programme, and heart rate (HR) were recorded. Faeces were collected on four separate days where the horses had been undisturbed at pasture for 48h. Social rank was determined through observations of social interactions during feeding. The fear test was a novel object test during which behaviour and HR were recorded.

Performance in the NR and PR learning tests did not correlate. In the NR test, there was a significant, negative correlation between performance and HR in the novel environment (rS=−0.66, P<0.001, i.e. nervous horses had reduced performance), whereas there was no such correlation in the home environment (both NR and PR). Behavioural reactions in the fear test correlated significantly with performance in the NR test in the novel environment (e.g. object alertness and final stage: rS=−0.43, P=0.04), suggesting that performance under unfamiliar, stressful conditions may be predicted by behavioural responses in a fear test. There was a negative correlation between social rank and baseline stress hormones (rS=−0.43, P=0.04), i.e. high rank corresponded to low FCM concentrations, whereas neither rank nor FCM correlated with fearfulness or learning performance. We conclude that performance under stressful conditions is affected by activation of the sympathetic nervous system during training and related to behavioural responses in a standardised fear test. Learning performance in the home environment, however, appears unrelated to fearfulness, social rank and baseline FCM levels.”

http://www.journals.elsevierhealth.com/periodicals/applan/article/S0168-1591(12)00168-2/abstract

Equine Welfare

Effect of head and neck position on intrathoracic pressure and arterial blood gas values in Dutch Warmblood riding horses during moderate exercise.

By Sleutjens J, Smiet E, van Weeren R, van der Kolk J, Back W, Wijnberg ID.

“OBJECTIVE:To evaluate the effect of various head and neck positions on intrathoracic pressure and arterial oxygenation during exercise in horses.

ANIMALS:7 healthy Dutch Warmblood riding horses.

PROCEDURES:The horses were evaluated with the head and neck in the following predefined positions: position 1, free and unrestrained; position 2, neck raised with the bridge of the nose aligned vertically; position 4, neck lowered and extremely flexed with the nose pointing toward the pectoral muscles; position 5, neck raised and extended with the bridge of the nose in front of a vertical line perpendicular to the ground surface; and position 7, neck lowered and flexed with the nose pointing towards the carpus. The standard exercise protocol consisted of trotting for 10 minutes, cantering for 4 minutes, trotting again for 5 minutes, and walking for 5 minutes. An esophageal balloon catheter was used to indirectly measure intrathoracic pressure. Arterial blood samples were obtained for measurement of Pao(2), Paco(2), and arterial oxygen saturation.

RESULTS:Compared with when horses were in the unrestrained position, inspiratory intrathoracic pressure became more negative during the first trot (all positions), canter and second trot (position 4), and walk (positions 4 and 5). Compared with when horses were in position 1, intrathoracic pressure difference increased in positions 4, 2, 7, and 5; Pao(2) increased in position 5; and arterial oxygen saturation increased in positions 4 and 7.

CONCLUSIONS AND CLINICAL RELEVANCE:Position 4 was particularly influential on intrathoracic pressure during exercise in horses. The effects detected may have been caused by a dynamic upper airway obstruction and may be more profound in horses with upper airway disease.”

http://www.ncbi.nlm.nih.gov/pubmed/22452499

More information on the above paper can be found at http://www.thehorse.com/ViewArticle.aspx?ID=20201

On the significance of adult play: what does social play tell us about adult horse welfare?

By Martine Hausberger, Carole Fureix, Marie Bourjade, Sabine Wessel-Robert and Marie-Annick Richard-Yris

“Play remains a mystery and adult play even more so. More typical of young stages in healthy individuals, it occurs rarely at adult stages but then more often in captive/domestic animals, which can imply spatial, social and/or feeding deprivations or restrictions that are challenging to welfare, than in animals living in natural conditions. Here, we tested the hypothesis that adult play may reflect altered welfare states and chronic stress in horses, in which, as in several species, play rarely occurs at adult stages in natural conditions. We observed the behaviour (in particular, social play) of riding school horses during occasional outings in a paddock and measured several stress indicators when these horses were in their individual home boxes. Our results revealed that (1) the number of horses and rates of adult play appeared very high compared to field report data and (2) most stress indicators measured differed between ‘players’ and ‘non-players’, revealing that most ‘playful’ animals were suffering from more chronic stress than ‘non-playful’ horses. Frequency of play behaviour correlated with a score of chronic stress. This first discovery of a relationship between adult play and altered welfare opens new lines of research that certainly deserves comparative studies in a variety of species.”

http://www.springerlink.com/content/a773802p37590541/

Training the Ridden Horse

Horse walker use in dressage horses

By T.J. Walker, S.N. Collins and R.C. Murray

“Horse walkers have become popular in the modern exercise regime for dressage horses, however recent investigations of injury risk factors have indicated a significant association between horse walker use and lameness. A detailed telephone questionnaire was conducted to document horse walker usage and assess whether horse walker use could predispose dressage horses to lameness. Information on horse walker features and use, and individual horse lameness history was recorded. Chi-squared tests were performed to identify horse walker variables associated with lameness. Although analyses failed to establish a direct link between lameness and any specific horse walker feature, the high proportion of lame horses in this study suggests that there is an underlying and, as yet, unidentified cause of lameness related to horse walker usage.”

http://wageningenacademic.metapress.com/content/j3q3511435340324/

The effect of double bridles and jaw-clamping crank nosebands on temperature of eyes and facial skin of horses

By Paul McGreevy, Amanda Warren-Smith and Yann Guisard

“Any apparatus that restricts a horse’s movement can compromise welfare. Eye temperature as measured remotely using infrared thermography is emerging as a correlate of salivary cortisol concentrations in horses. This article explores the effect on the temperature of the eyes and facial skin of horses wearing devices that restrict jaw movements. In certain equestrian disciplines, unacceptable equine oral activity, such as gaping of the mouth, is penalized because it reflects poor training and lack of compliance. This explains the wide range of nosebands and flash straps designed to prevent the mouth opening. Some of these nosebands are banned from higher-level dressage competitions in which double bridles are mandatory, possibly because they are regarded as restrictive. Nevertheless, the current international rules overlook the possibility that noseband can appear innocuous even though some designs, such as the so-called crank noseband, can be ratcheted shut to clamp the jaws together. Some equestrian manuals and competition rule books propose that “two-fingers” be used as a spacer to guard against overtightening of nosebands but fail to specify where this gauge should be applied. The vagueness of this directive prompted us to undertake a small random survey of the finger dimensions of adult men (n = 10) and women (n = 10). There were significant sex differences in the measurements of fingers of adults (P < 0.001), thus illustrating that the “two-finger rule” is not a reliable guide for standardized noseband fastening. Infrared thermography was used to measure the temperature of facial skin and eyes of adult horses (n = 5) wearing a double bridle with and without a cavesson noseband.

A taper gauge was developed based on the mean circumference of adult index and middle fingers (9.89 ± 0.21 cm), and this was used as a spacer at the nasal planum or beside the mandible when tightening the noseband. The nosebands were fastened significantly tighter when the taper gauge was used beside the mandible than at the nasal planum (P = 0.02). Wearing double bridles and nosebands that had been tightened with and without the taper gauge caused an increase in eye temperature compared with baseline values (P = 0.012), and the tighter the noseband was fastened, the cooler the facial skin of the horse (and, presumably, the greater the impairment of vascular perfusion) when compared with baseline values (P = 0.016). This study suggests that horses wearing double bridles and tight nosebands undergo a physiological stress response and may have compromised vascular perfusion. Consequently, on welfare grounds, the use of nosebands that cause any constriction of jaw movement should be reviewed as soon as possible.”

http://www.journalvetbehavior.com/article/S1558-7878(11)00143-2/abstract

Pilot study of behavior responses in young riding horses using 2 methods of making transitions from trot to walk

By Agneta Egenvalla, Marie Eisersiöb and Lars Roepstorffc

“According to the principles of negative reinforcement, when an aid has been given to an animal, it should be released as soon as the desired response has been achieved, and, if performed well, may be associated with fewer conflict behaviors than otherwise. In riding, pressure in the horse’s mouth from the bit is used to give signals to the horse, and both rein tension and patterns of releasing this tension will vary. The aim of this pilot study was to study horse behavior during 2 different methodologies used to shape relatively naïve horses to a deceleration signal while making downward transitions from trot to walk. Method 1 involved relief from rein tension at the first attempt to perform a correct response (M1), and method 2 entailed that rein tension was relieved at the completed correct response (M2). Four horses were ridden by 4 riders over 4 days (1 rider each day), and each horse made 10 transitions each day for each method, which produced 320 transitions. Rein tension was recorded, and horse behavior and rider signal behaviors were evaluated from video recordings. Horse behavior was divided into the following 3 different categories: “pushing against the bit,” “moving away from the bit,” and “decelerating.” Linear models were constructed tracking the percent of the transition time that horses demonstrated at least 1 behavior in the “pushing against the bit,” “moving away from the bit,” and “decelerating” categories, and with random effects for rider, horse, and transition number nested within horse. Fixed effects analyzed were the methods, proportion of the transition time above 30 N for each rein, and the rider signal behaviors. M1 and M2 had on average 19% (standard deviation: 16) and 38% (standard deviation: 23) of the time with >30 N per rein, respectively. In the models for the “pushing against the bit” behaviors, M2 increased rein tension and “exerting pressure on the reins” increased the level of these behaviors. “Releasing pressure” interacted with “pulling back on the reins”; this combination was associated with an increased level of “pushing against the bit” behaviors. The “decelerating” behavior was associated with lower rein tension. In the “decelerating” behavior models, “pulling back on the reins” led to decreased “decelerating” behavior, whereas “still hand” and “releasing pressure” led to increased “decelerating” behavior; however, the interaction “pulling back on the reins” and “releasing pressure” led to decreased “decelerating” behavior. “Moving away from the bit” had no significant determinants. We concluded that fewer “pushing against the bit” behaviors were created by M1 and that a lower rein tension was associated with the “decelerating” behavior. Reinforcing the horse’s attempts, to assist in finding the correct response, benefits the welfare of the horse, and importance of a light hand should be continuously emphasized during riding education.”

http://www.sciencedirect.com/science/article/pii/S1558787811001481

Equipment and training risk factors associated with ridden behaviour problems in UK leisure horses

By Jo Hockenhull and Emma Creighton

“Ridden behaviour problems are prevalent in the UK leisure horse population and may have implications for horse welfare and rider safety. This study aimed to identify risk factors associated with ridden behaviour problems in UK leisure horses from the training approaches and equipment used with them. An Internet survey was used to collect data on 1326 horses from a convenience sample of leisure horse owners. The survey asked owners to report the frequency their horses displayed fifteen ridden behaviour problems over the previous week. Data on the frequency of occurrence of behaviour in four components of related ridden behaviour problems were explored for association with details of the horse’s working life, including the type of tack, equipment and training used, and the frequency the professional services of saddlers and farriers were employed using logistic regression analyses. Behaviour data were generated for 791 individual horses. Risk factors associated with the ridden behaviour problems emerged as three themes. One related to the design and fit of the saddle, with dressage and working hunter saddles associated with a reduced risk of ridden behaviour problems compared to general purpose saddles. The horse’s footcare and shoeing regime was associated with three of the four groups of behaviour problems. An extended interval (seven weeks or more) between farrier visits was associated with an increased risk of discomfort behaviour. Taking an outcome-centred approach to training, for example through the use of artificial training aids, was associated with an increased risk of behaviour problems while spending more time with the horse outside of training situations, a more horse-centred approach, was associated with a reduced risk of problems. Further research is required to understand the causal relationships behind these associations, with the aim of improving the welfare of the horse and the well-being and safety of its rider.”

http://www.journals.elsevierhealth.com/periodicals/applan/article/S0168-1591(12)00020-2/abstract

I hope you enjoy this collection of abstracts as much as I did. If you have a question about any of the abstracts or the terminology used, please feel free to leave a comment or email me and I will happily answer your questions.

Emma Lethbridge

(Emma@theequineindependent.com or E.M.Lethbridge@shu.ac.uk)

Jul 142010
 

Summer is a great time for riders and horse owners alike, the long days and hopefully sunny weather bring greater opportunities for spending time with our much loved, four-legged friends. However, for some horse and pony owners summer can also be a worrying time and the start of an ongoing battle with their horse’s waistline. Despite our best intentions summer comes and our horse’s stomachs begin to expand like balloons at a birthday party. Some horses come out of winter the perfect weight but can start to inflate the minute the first spring grass appears, for others the issue of weight is a constant factor, especially for those with pony or cold blood genes in their DNA. If you own a horse who is a ‘good doer’ and he can seemingly live off air alone, it can seem like no management strategy or exercise regime will stop the spread. So what are the real risk factors of obesity and how can we prevent our horse’s becoming overweight this summer?

Obesity, in both horses and humans, is becoming an epidemic in the UK. The horse charity, World Horse Welfare, estimates that between 35 and 45 per cent of the UK’s 1.35million horses are obese[1]. There are many worrying disorders that obesity is associated with, including; Laminitis, Equine Metabolic Syndrome and oxidative stress[2]. All of the above disorders are of grave concern to owners! Laminitis is inflammation of the digital laminae of the hoof. The digital laminae are necessary for suspension of the skeleton within the hoof and spread the concussive forces experienced by the hoof during the horse’s locomotion. Inflammation of the laminae weakens the hoof and can have devastating effects on the horse’s physiology included; sinking and rotation of the coffin bone (known as founder), separation of the hoof wall from the hoof capsule, rotation of the coffin bone and penetration of the coffin bone through the sole of the hoof[2]. These complications of Laminitis can cause permanent lameness and loss of use and can, in the worst cases, result in euthanasia.

Equine Metabolic Syndrome (EMS) is characterised by obesity, insulin resistance and intermittent bouts of Laminitis[2]. Obese horses suffering with EMS become gradually more resistant to the action of insulin – insulin is a hormone which triggers cells in the liver, muscles and fat to take up glucose from the blood stream and store it as glycogen. This resistance to insulin consequently causes abnormally high levels of insulin to be secreted when the horse ingests food, especially foods high in sugars such as concentrate. In both horses and humans, insulin resistance seems to be correlated with obesity and the altered metabolism of fats[3]. However, unlike in the human species, insulin resistance in horses due to obesity is very rarely type 2 diabetes (diabetes in horses is usually only associated with Cushing’s syndrome), instead insulin resistance is postulated to be a contributing factor to Laminitis and potentially certain vascular diseases[3].

Laminitis and EMS are not the only concerns for the owners of horses who put on weight easily. Several adverse health effects can be correlated with the horses gain of fat deposits. The horse may become intolerant of exercise and his athleticism will be compromised. Just as obese humans can experience oxidative stress, fatigue and increased concussion on joints during exercise, horses can also experience these consequences of obesity. The performance of horses competing in races of duration 1 mile to 160km has been found to correlate to the horse’s body condition[4-6]. The obese horse may also experience thermoregulatory difficulty, although fat deposits will insulate a horse during the winter months, in the summer excess fat can prevent the horse from effectively dissipating heat resulting in the horse overheating[7]. Finally, abnormal reproductive performance has also been observed in obese mares [8], obesity can cause unnecessary complications in pregnancy and is therefore a welfare concern for both mare and foal. The risks of horse obesity are very worrying for horse owners so why are so many horses becoming obese in the UK?

Although ignorance on behalf of the horse owner is sometimes the underlying cause of equine obesity, most owners are aware when their horses are becoming overweight. Even the least observant owner can see their horse’s stomach increasing in girth, the neck becoming larger and developing a crest, and fat deposits occurring on the shoulders and flanks, but often the owner is struggling to set up a management regime that can control the weight of the horse. Owners are often restricted by factors such as; the residence of the horse, the management of the horse’s pasture or other environmental factors. But do not despair, here are a few ideas which could help to prevent the summertime spread this year.

1. Knowing how much you horse should weigh, finding an accurate way to measure your horse’s weight and keeping a record of change.

The first thing you will need to know when you embark on the battle with obesity is your horse’s ideal weight. Without a goal weight for your horse any measurement of the horse’s weight is going to be arbitrary. Although all horses differ with regards to their ideal weight, approximate ideals for your horse’s type and height can be found below. For each height range there is a range of ideal weights, if your horse is the top end of the height range or a draught bred then the horse’s ideal weight will be the top end of the range, and vice versa.

Height in hands 11 12 13 14 15 16 17
Ideal weight in kg 120-230 230-290 290-350 350-420 420-520 520-600 600-725

(Adapted from Baileys Horse feeds [9])

Once you know your horse’s ideal weight you will need to be able to measure the horse’s weight. There are many ways to measure a horse’s weight, some more accurate than others. The most accurate method of measuring a horse’s weight is a weighing bridge, however unless you are liveried at a very well equipped yard or have convenient access to veterinary facilities it is unlikely that you will have access to a weigh bridge.

A more common method of measuring a horse’s weight is by using a weight tape. Weight tapes are placed around the girth of the horse, just behind the withers, and give an estimation of the horse’s weight based on the circumference of the girth . The accuracy of these tapes is debatable however, the tape provides a quantitative measure of weight which can be recorded and which will provide notice of the horse’s weight changing over time. Weight tapes can be brought from most equestrian stores, and on occasion tapes specifically designed for draught horses and ponies can be acquired. Buying a tape designed for your horse’s body type will increase the accuracy of the measurement.

As an alternative measure of the horse’s weight and condition there are body condition scoring systems, one of the most popular is based on work by Henneke et al (1983)[10]. Henneke et al’s body condition scoring uses the observation and ranking of the fat tissue present on specific areas of the body to score the condition of the horse. The areas observed for the accumulation of fatty tissue are; the neck, ribs, back, shoulder, wither and the top of the tail. When all the areas are taken into consideration an overall condition score, between 1 and 9, is attributed to the horse – 1 being of very poor condition with no fatty tissue present in the scored areas and 9 being of obese condition with significant fatty deposits visible on the . A picture chart explaining Heneke’s body condition scoring can be found at – http://www.admani.com/allianceequine/images/bodyconditionscoring/horse%20body%20condition%20score%20card.pdf , this picture chart is a good summary of the observations that should be made during condition scoring. A printable record sheet for Henneke et al’s body condition scoring mechanism can also be found at this link – http://www.blm.gov/pgdata/etc/medialib/blm/wo/Information_Resources_Management/policy/im_attachments/2009.Par.52473.File.dat/IM2009-041_att1.pdf

There are potential problems with using body condition scoring as a method of weight measurement in horses. Scoring body condition is a subjective method and it is therefore possible for owners to over or under score their horses and, if no additional methods of weight measurement are used, it is sometimes difficult to ascertain whether the horse is indeed of a healthy weight. Ideally two or three people should score the horse independently and the middle score taken to be correct, such a precaution will help to minimise the effect of subjective bias. The body score of the horse can be recorded and over time any change in the horse’s condition can be monitored accordingly.

Whichever method of weight measurement you decide to use with your horses, try to keep a record at least once a month of the horse’s weight. This record keeping will allow you to see changes in the horse’s condition early and allow you to change his management before serious complications arise.

2. Cutting out the concentrate feed!

This one may seem obvious, but if your horse is overweight it is not necessary to supplement the horse’s roughage feed with concentrate! Removing concentrate feed, and therefore unnecessary calories, from the diet of the horse will help to prevent, or treat, obesity. If the horse is feed ad-lib, quality roughage including pasture, and is a good weight it is not necessary to supplement the horse’s diet with calorie-dense, grain concentrate. Should the horse’s pasture and roughage be of poor quality it may be a prudent idea to add a vitamin and mineral supplement to the horse’s feed, this will prevent any dietary malnutrition. As long as the horse maintains weight and does not become thin, and is not in a heavy exercise regime, i.e. intermediate eventing or above, the horse does not require extra calories. Should the horse be currently in a routine where he is used to receiving concentrate meals at certain times and will become distressed if his routine is changed then some molasses-free chaff or grass chop can be feed at these times to placate him.

3. Pasture maintenance

There are many aspects of pasture maintenance that can be managed to help combat obesity and weight gain in the horse. Below I will tackle the most important factors of pasture maintenance that can be managed by horse and land owners –

The right grass?

Many grassland species have been selectively produced to feed domestic livestock on intensive grazing patterns, as such many grass species commonly found in horse grazing are high in sugars. Grass designed to keep livestock at a good weight is often too rich for horses who are designed by evolution to each a great amount of poorer roughage. See below abstract by Menard et al (2001)[11] on the comparative forage intake of cattle and horses.

“Equids are generalist herbivores that co-exist with bovids of similar body size in many ecosystems. There are two major hypotheses to explain their co-existence, but few comparative data are available to test them. The first postulates that the very different functioning of their digestive tracts leads to fundamentally different patterns of use of grasses of different fibre contents. The second postulates resource partitioning through the use of different plant species. As domestic horses and cattle are used widely in Europe for the management of conservation areas, particularly in wetlands, a good knowledge of their foraging behaviour and comparative nutrition is necessary.

In this paper we describe resource-use by horses and cattle in complementary studies in two French wetlands. Horses used marshes intensively during the warmer seasons; both species used grasslands intensively throughout the year; cattle used forbs and shrubs much more than horses. Niche breadth was similar and overlap was high (Kulczinski’s index 0·58–0·77). Horses spent much more time feeding on short grass than cattle. These results from the two sites indicate strong potential for competition.

Comparative daily food intake, measured in the field during this study for the first time, was 63% higher in horses (144 gDM kg W−0·75 day−1) than in cattle (88 gDM kg W−0·75 day−1). Digestibility of the cattle diets was a little higher, but daily intake of digestible dry matter (i.e. nutrient extraction) in all seasons was considerably higher in horses (78 gDM kg W−0·75 day−1) than in cattle (51 gDM kg W−0·75 day−1). When food is limiting, horses should out compete cattle in habitats dominated by grasses because their functional response is steeper; under these circumstances cattle will require an ecological refuge for survival during winter, woodland or shrubland with abundant dicotyledons.

Horses are a good tool for plant management because they remove more vegetation per unit body weight than cattle, and use the most productive plant communities and plant species (especially graminoids) to a greater extent. They feed closer to the ground, and maintain a mosaic of patches of short and tall grass that contributes to structural diversity at this scale. Cattle use broadleaved plants to a greater extent than horses, and can reduce the rate of encroachment by certain woody species.”

Menard et al (2001)


As horses can consume great amounts of forage it is vital that the high-sugar, easily digestible and nutrient rich grass varieties fed to domestic livestock species are not feed in high quantity to horses. Obesity and laminitis will be difficult to avoid on rich grazing without restricting grazing, which in turn would be detrimental to the welfare of the horse. Sugars present in grass species, especially fructans have been correlated with laminitis in horses. Below is an informative short article on fructans from www.equinescienceupdate.co.uk.

Recent studies suggest that fructans might be involved in pasture-induced laminitis in horses. Fructans are storage molecules produced by the grass when it produces more sugars by photosynthesis than are needed for immediate use. Fructans are poorly digested in the foregut of the horse. If large quantities reach the hindgut they are rapidly fermented by the microorganisms, leading to a cascade of events that may result in laminitis.

In a three year study Jürgen Grässler and Uwe von Borstel, working at the Landwirtschaftskammer in Hannover, Germany, looked at fructan content in the species of grasses that are commonly found in horse pasture. They harvested grass samples every two or three weeks during the growing season. Samples were collected at 11.00 each morning to prevent the results being influenced by time of day.

Dr Grässler presented their findings at the Equine Nutrition Conference held earlier this month in Hannover. They found that Lolium perrene (Perennial ryegrass) and Lolium multiflora (Italian ryegrass) contain the highest amounts of fructans – an average throughout the year of 5.7% on a dry matter basis. However, they found that the fructan content varied throughout the year, being highest in May and October. The fructan content fell during the summer. They also found a difference between strains of perennial ryegrass. One strain (“Anton”) had the highest fructan level of 14.2%DM in autumn 2003 and 13.6% DM in spring the same year.

All other pasture grasses contained low fructan concentrations – on average about 3.5% DM. Again, the highest fructan concentration was found in the first growth in May and in October. The fructan content of the grass was lowest during the summer.

The second part of the study looked at the fructan content of grass mixes that might be used for horse pasture. Grässler and von Borstel found that mixtures with a high proportion of Lolium perrene gave the highest fructan levels . The highest levels were found in pastures containing only Lolium perrene (15.2%). During the growing season the highest fructan content was measured in late June (11.4% DM average) and in October.

Grässler and von Borstel conclude that grass mixes with high amounts of Lolium perrene may contain high fructan concentrations, especially in spring and autumn, and are less suitable for feeding horses predisposed to laminitis.

To minimise the risk of laminitis they suggest that grass mixtures with reduced quantities of Lolium perrene should be used. Pastures with forage grasses such as Alopecurus pratensis (Meadow Foxtail) and Phleum pratense (Timothy) as the main components are suitable to produce low fructan concentrations.

Reference: Fructan content in pasture grass. Jürgen Grässler and Uwe von Borstel. Proceedings Equine Nutrition Conference. Pferdeheilkunde (2005) 21, 75 – 76.”[12]

The key message of the above article is; when planning the reseeding of your pasture please consider the grass species you are using and choose low-sugar grass species, such as Meadow Foxtail and Timothy, which will protect your horses against obesity, insulin resistance and Laminitis. Herbs and legumes can also be included for variety and additional vitamin and mineral availability. Sugar-dense grasses used to feed domestic livestock, such as dairy cattle, should be avoided as they are not suitable for healthy horse grazing. Rye grass is the typical example and is currently very common in the pastures of Britain’s horses. If you are at the mercy of a land owner it may be possible through democratic negotiation to encourage the seeding of horse friendly grass species.

Pasture fertilisation

Traditionally pasture fertilisation is recommended in the spring and autumn months. It is suggested that proper fertilisation will provide pasture with the nutrients to produce a good quantity of grass cover, minimising weed growth. In addition it is postulated that the nutrients needed to provide horses with a healthy diet are also infused into the soil during fertilisation. However, the relationship between fertilisation and grass nutrition is not straight forward, especially when considering non-structural carbohydrate concentrations (sugars). It is often assumed that fertiliser increases the sugar content of grass, however, it is well noted in scientific journals that grass grown in an environment deficient in either nitrogen or phosphorus is observed to be significantly higher in sugars than grass grown in fertilised conditions [13, 14, 15, 16]. The discovery of this correlation between nitrogen availability and the sugar concentration in grass has led to the postulation that nitrogen maybe a limiting factor for growth and therefore if the grass becomes deficient in nitrogen, growth stops and, rather than being used for the production of new plant matter, fibre and energy, the sugars accumulate in the grass[17].

In her 2005 paper titled – A Review of Unlikely Sources of Excess Carbohydrate in Equine Diets, Kathryn Watts considers data collected on the effect of pasture fertilisation on the non-structural carbohydrate (NSC) concentrations of grass, and how pasture should managed to prevent an excess in sugar in the equine diet[17]. She writes “The following data was collected from the first cutting of forage from an established paddock of irrigated pasture at Rocky Mountain Research & Consulting, Inc. Each treatment was replicated 4 times in a randomized block design. The species represented are mostly Paddock meadow brome and Garrison meadow foxtail, which are standard commercial varieties in the area. Ammonia nitrate was broadcast in March, and irrigation was applied as needed for optimum growth to both fertilized and unfertilized plots. When the paddock was starting to head the end of May, samples for NSC were collected 4 PM, frozen immediately, and shipped frozen for analysis. A light frost occurred the night before sampling. The next day, 2 sq yards of plant material were hand clipped to ground level from each plot, and dried in an oven to obtain dry matter yield. The plots fertilized with ammonia nitrate yielded 3 times more dry matter, and were 29% lower in NSC concentration than unfertilized. This inverse relationship between nitrogen content and NSC concentration corroborates that found in plant science literature.

NSC %

Dry matter

Yield Tons

Dm/ acre

Pounds NSC /acre
35 lbs/acre

nitrogen as AmNO3

17.88 b 1.8 a 643 a
No nitrogen 23.10 a .6 b 277 b

Analysis by Dairy One, Ithaca, NY

The determination as to whether NSC concentration or pounds of NSC per acre is more important will be dependent on how the individual horse’s intake is managed. If a horse has continual access to pasture, it is possible to limit grass intake by starving the grass for nitrogen and overgrazing such that the amount of available forage does not exceed or even meet caloric needs. In this scenario, additional hay is often required. Because hay is generally lower in NSC than fresh grass, the higher concentration of NSC in nitrogen deficient grass may be offset by the lower concentration generally found in hay. In this type of situation, susceptible horse’s may be at increased risk of over indulging if the pasture is fertilized or irrigated, or a drought breaking rain occurs, which would then create more pounds of NSC per acre, while removing the limitations to intake imposed by slow grass growth.

If the caretaker were limiting intake by restricting access to grass, by use of grazing muzzle, portable fencing, or removal to a dry lot for part of the day, then fertilization, which decreases the concentration of NSC per mouthful of grass, would be the best option.” [17]

When considering whether it is healthier for your horses to fertilise your paddock or to leave it to grow organically it is necessary to consider whether the higher yield of grass obtained through fertilisation is likely to cause your horse to have higher sugar in his diet than the lower yield, higher sugar concentration grass of organic pasture? If your horse’s residential property has a low horse-acreage ratio, then it is possible that the high yield gained by fertilisation will create to much pasture for the horses to graze without becoming overweight. However, if there are a significant amount of horses grazing the pasture of your horse’s residence the extra grass yield of fertilised pasture should be spread between enough animals that the lower sugar concentration of fertilised grass is beneficial. Optimum fertilisation is a balancing act, one that must be considered carefully by horse owners.

To be continued….

Next time we will consider more pasture management ideas and exercise routines design to fight horse flab.

By Emma Lethbridge

(info@emmalethbridge.com)

References

[1] http://www.worldhorsewelfare.org/

[2] Johnson P.J., Wiedmeyer C.E., Messer N.T., Ganjam V.K. Medical Implications of Obesity in Horses—Lessons for Human Obesity. J Diabetes Sci Technol. 2009; 3(1): 163–174.

[3] Hoffman R.M., Boston R.C., Stefanovski D, Kronfeld D.S., Harris P.A. Obesity and diet affect glucose dynamics and insulin sensitivity in Thoroughbred geldings. J Anim Sci. 2003;81(9):2333–2342.

[4] Kearns C.F., McKeever K.H., Kumagai K., Abe T. Fat-free mass is related to one-mile race performance in elite standardbred horses. Vet J. 2002;163(3):260–266

[5]Lawrence L.M., Jackson S., Kline K., Moser L., Powell D., Biel M. Observations on body weight and condition of horses in a 150-mile endurance ride. J Equine Vet Sci. 1992;12:320–324.

[6]Garlinghouse S.E., Burrill M.J. Relationship of body condition score to completion rate during 160 km endurance races. Equine Vet J Suppl. 1999;30:591–595.

[7] Cymbaluk N.F., Christison G.I. Environmental effects on thermoregulation and nutrition of horses. Vet Clin North Am Equine Pract. 1990;6(2):355–372.

[8] Henneke D.R., Potter G.D., Kreider J.L. Body condition during pregnancy and lactation and reproductive efficiency of mares. Theriogenology. 1984;21:897–909.

[9] http://www.baileyshorsefeeds.co.uk/feedingexplained/calculator.htm

[10] Henneke D.R., Potter G.D., Kreider J.L., Yeates B.F. (1983). Relationship between condition score, physical measurements and body fat percentage in mares. Equine Vet J. 15(4):371-2

[11] Menard C., Duncan P., Fleurance G., Georges J-Y., Lila M. (2001). Comparative foraging and nutrition of horses and cattle in European wetlands. Journal of Applied Ecology. 39 (1); 120-133.

[12] Article at http://www.equinescienceupdate.co.uk/fructan.htm on the paper- Fructan content in pasture grass. Jürgen Grässler and Uwe von Borstel. Proceedings Equine Nutrition Conference. Pferdeheilkunde (2005) 21, 75 – 76.

[13] Smith D. Nonstructural Carbohydrates. In Butler G.W., Bailey R.W. ed. Chemistry and Biochemistry of Herbage, vol 1. London: Academic Press, 1973;105-155.

[14] Belesky D.P., Wilkinson S.R., Stuedemann J.A. The influence of nitrogen fertilizer and Acremonium coenophialum on soluble carbohydrate content of grazed and non-grased Festuca arundinace., Grass Forage Sci 1991;46:159-166.

[15] Donaghy D.J., Fulkerson W.J. The impact of defoliation frequency and nitrogen fertilizer application in spring on summer survival of perennial ryegrass under grazing in subtropical Australia, Grass Forage Sci 2002;57(4):351.

[16] Morvan-Bertrand A., Boucaud J., Prud’homme M. Influence of initial levels of carbohydrates, fructan, nitrogen and soluble proteins on regrowth of Lolium perenne . L. cv. Bravo following defoliation. J Exper Bot 1999;50:1817-1826.

[17] Watts K.A. A Review of Unlikely Sources of Excess Carbohydrate in Equine Diets. Journal of Equine Veterinary Science. 2005; 25(8): 338-344

May 142010
 

Dietary supplementation for horses is a vexed area where the scarcity of scientific studies, owners’ desires to do the best for their animals and enthusiastic advertising by manufacturers all conspire to make it difficult for anyone to know the best thing to do.

There is nothing inherently dodgy or implausible about vitamins and trace elements. They are essential to life. Strictly speaking, a vitamin is a substance that has to be obtained from the diet because the organism involved is unable to manufacture, or synthesise, it in its body. For example, vitamin C or ascorbic acid is a vitamin for people but not for horses. Horses synthesise this substance in their guts; people do not, and depend on a dietary supply. A trace element is, as its name suggests, a chemical element or nutrient that is required by the body in minute, or trace, amountsIt has long been known that dietary deficiencies can lead to illness (Wikipedia 2010a), although it was not until the early part of the 20th century that all the vitamins were isolated and described. It is also indisputable that until fairly recent times, vitamin and trace element deficiencies were common in humans even in the developed countries, and in less fortunate parts of the world this is still so.

The discovery of vitamins, and the ability to manufacture them commercially, soon led to a highly profitable industry selling supplements. Once the preserve of the whole-food shop, dazzling arrays of supplements are now de rigueur almost anywhere that food and, indeed, medicines are sold. The beliefs that routine supplementation is good for everyone, that most diets are deficient and that many people have special needs for extra micronutrients have all been promoted way beyond the actual evidence, to the point where many people not only take multivitamins routinely, but take them well in excess of the recommended daily doses. Unfortunately, recent studies are showing that when it comes to vitamins and trace elements it is possible to have too much of a good thing, and substances that are vital for health in small doses can be dangerous in larger amounts. This is hardly surprising: these substances are biologically active, and all biologically-active substances are likely to have side effects as well as main effects. For people living in developed countries, the scientific evidence at present is that there are no proven benefits to routine supplementation, that modern foodstuffs are not deficient in nutrients, that most people in industrialised countries can get all of their nutritional needs from food, and that high doses of vitamins probably do more harm than good (Hall 2008; Novella 2009; Skeptvet 2009, Carroll 2010).

Might this be the case also in horses?

Equine nutritional supplements have been something of a growth industry over the last 20 or 30 years. Your average tack shop or feed store now incorporates an impressive display of vitamins, minerals and other feed additives and there are hundreds of vitamin and mineral mixes sold for horses, even though the recommended daily allowances and maximum and minimum safe levels for horses are not at all well known (Merck 2008). In the last few months I’ve seen advertising that suggests that all soils, in the UK at least, are deficient in minerals, that all pasture and hay is therefore deficient, and that all horses therefore need to be given supplements. It is very difficult to find any hard evidence on this subject. In temperate climates there are localised areas of nutrient deficiencies in the soil, and these can affect the health and growth of ruminant livestock such as sheep and cattle depending on how intensively the land is managed (Whitehead 2000), but I’ve not been able to find any comparable data for horses that is independent and doesn’t come from somebody selling supplements. If any reader can point me to any, please do.

It appears that vitamin and mineral deficiencies in the horse are actually rather rare (Merck 2008) and generally follow some other problem such as starvation or malabsorption because of age or illness. Horses’ bodies manufacture vitamin A from beta-carotene and vitamin C from sucrose in the diet. All the B vitamins and vitamin K are synthesised by the bacteria in the equine gut. Vitamin D is produced by the action of ultraviolet light on the horse’s skin. In fact the only vitamin needed by the horse that has to come from its diet is vitamin E (Kerrigan 1986). There are adequate levels of the essential trace elements in most pastures and hay for a horse doing light to moderate work, and not otherwise stressed (Wikipedia 2010c). A horse who has reasonable access to sunlight and green, growing pasture or sun-cured forage is unlikely to be deficient in any vitamins. Mineral deficiencies can arise, but these are rarely a consequence of the pasture a horse is in and more commonly a result of faulty feeding. The trace elements most likely to be deficient are calcium, phosphorus, copper, sodium chloride (salt) and selenium (Merck 2008).

It is more common for horse rations to contain an excess of certain nutrients, and this can lead to direct toxicity or to induced deficits of other minerals. Phosphorus, iron, copper, selenium and vitamin A are the substances most commonly fed to excess (Merck 2008).

In horses, the best-known example of a nutritional disorder is nutritional secondary hyperparathyroidism, also known as big-head disease or bran disease. It is caused by a diet containing too much phosphorus and too little calcium, and was prevalent in western Europe when many horses were fed large amounts of wheat bran. Although the link between bran in the diet, calcium deficiency and bone weakness was established by the veterinary surgeon Dr Varnell in 1860, the condition was still occasionally being diagnosed in the 1980s in horses fed excessive amounts of grain (Hintz 1987). It is still common in horses grazing certain tropical grasses, where chemicals called oxalates in the grasses combine with calcium so that it cannot be absorbed by the horse’s gut.

Selenium and vitamin E deficiencies have been considered as possible risk factors in horses prone to exertional rhabdomyolysis (tying up or azoturia) but the evidence is by no means unequivocal: if your horse suffers from this condition it is sensible to have a vet blood-test your horse and supplement, if necessary, under expert supervision. This is definitely not one to guess at yourself as even a slight excess of selenium can cause irreversible damage including loss of mane and tail hair and sloughing of the hooves (Merck 2008), and large overdoses can cause death (Wikipedia 2010b).

As for the known toxic and harmful effects of overdoses: vitamin A in excess can damage the bones and skin and cause developmental problems in unborn foals, and too much vitamin D can cause calcium to be laid down in the blood vessels, heart and soft tissues as well as bone weakness and weight loss. It can be fatal. Iodine toxicity, resulting in an enlarged thyroid gland (goitre) can occur in horses fed too much dried seaweed. Too much potassium can cause heart problems. Feeding magnesium to excess – possible if you give your horse a fortified diet and also a magnesium-based ‘calmer’ – may interfere with calcium absorption and lead to a deficiency of that mineral. Iron excess can interfere with the metabolism of copper. Too much copper can cause problems with the uptake of selenium and iron (Merck 2008).

Current veterinary advice is that a horse in light to moderate work who is fed a balanced diet with plenty of good-quality forage (including hay or haylage and decent grazing), who spends at least 4 hours a day outdoors in order to metabolise vitamin D from sunlight and who is not in extremely hard work is, if otherwise healthy, unlikely to need any supplementation except for common salt, sodium chloride, which may be given as a free-access lick or added to the feed (Merck 2008). There are, however, circumstances in which it is possible for a horse to suffer from deficiencies. The most obvious is the fat horse or pony who needs to be on a severely restricted diet in order to control his weight. He may not be getting enough food to fulfil his needs for vitamin precursors (the substances that are converted to vitamins in the digestive tract) or trace elements, especially if his diet is based on soaked or poor-quality forage. Phosphorus deficiency can occur in horses eating poor-quality forage and no grain. It leads to weakening of the bones and low-grade lameness, but the owner is likely to notice the horse eating soil or other non-foods before any clinical signs develop. Very old horses may need supplements to compensate for the reduced efficiency of their digestive processes. Horses kept permanently stabled or rugged may have vitamin D deficiency as a result of insufficient sunlight on the skin. Horses in very hard work that makes them sweat a lot will benefit from electrolyte supplements to compensate for the sodium and potassium lost in sweat. If they are also fed high-fat diets they may need extra vitamin E. Horses who are chronically stressed, or ill, may have higher than normal requirements for some vitamins and trace elements. Pregnant and lactating mares may need supplements too (Wikipedia 2010c).

If your horse does have a clinically significant deficiency, he might need a higher level of supplementation than he’d get in an all-purpose vitamin and mineral mix, so it is worth having a proper test and just giving him what he really needs. In fact, if you have any suspicion that your horse may have a vitamin or trace element deficiency, it is far better for your bank balance and his health and soundness to have him blood-tested, and to adjust his diet accordingly.

For obvious reasons, it is best to have this test done by your vet and not by a company who is selling supplements and who has a vested interest in finding a deficiency. Nutritional deficiencies are easily and inexpensively diagnosed using blood serum analysis and this is the only reliable way of doing it. I wouldn’t personally be tempted by alternative diagnostic techniques such as hair analysis (Barrett 2008) or applied kinesiology (Barrett 2009) as they haven’t been shown to work in independent tests and in many cases the person or company offering the technique is also selling supplements. Do-it-yourself diagnosis and treatment also has its risks. I have heard of owners giving their nervous horses magnesium and vitamin B supplements ‘because they are essential for the proper working of the nervous system’ – and so they are, but nervous behaviour isn’t necessarily the result of a disordered nervous system, and the horse may not actually be deficient in those substances. Even if these owners don’t cause any actual harm with their oversupplementation, they are spending money on products that will do no more than produce vitamin-rich and mineral-rich urine. There are cheaper ways to improve the nutritional status of your fields, if that is the problem.

In conclusion, though most horses are unlikely to need supplements, some may benefit from them. And if your horse is one of those who would benefit, it would seem most sensible and economical to find out what he actually needs, given that supplements cost money and that some are dangerous in large doses.

By Alison Averis

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References

Barrett S (2008). Commercial hair analysis: a cardinal sign of quackery. www.quackwatch.com/01QuackeryRelatedTopics/hair.html

Barrett s (2009). Applied Kinesiology: phony muscle testing for ‘allergies’ and ‘nutrient deficiencies’. www.quackwatch.com/01/QuackeryRelatedTopics/Tests/ak.html

Carroll R (2010). Vitamins. www.skepdic.com/vitacon.html

Hall, H (2008). Should I take a multivitamin? www.sciencebasedmedicine.org/?p=160

Hintz HF (1987). The nutrition and feeding of horses. In Veterinary notes for horse owners. Ed by P D Rossdale. 17th Edition. Stanley Paul, London.

Kerrigan, R (1986). Practical horse nutrition. Adelaide, Australia.

Merck & Co. inc. (2008) Nutrition: horses. www.merckvetmanual.com/mvm/index.jsp?cfile=htm/bc/toc_182600.htm

Novella S (2009). Another negative study of vitamins. www.sciencebasedmedicine.org/?p=372

Skeptvet (2009). Orthomolecular medicinebig talk, little evidence, real risk. www.skeptvet.com/Blog/2009/08/orthomolecular-medicine-big-talk-little-evidence-real-risk/

Whitehead DC (2000). Nutrient elements in grassland. CABI Publishing, Wallingford.

Wikipedia (2010a). Vitamins www.en.wikipedia.org/wiki/vitamins

Wikipedia (2010b). Selenium. www.wikipedia.org/wiki/selenium

Wikipedia (2010c). Equine nutrition. www.en.wikipedia/wiki/Equine_nutrition