The latest research on feeding, breeding and stable coughs *H&H VIP*

  • There are good and reliable guidelines concerning the feeding of stabled horses in moderate or hard work. Indeed, the feeding of high-performance racehorses, showjumpers, eventers and dressage horses has been the subject of considerable research. Commercial feeds are blended and produced on the basis of this research and all large feed manufacturers have highly qualified in-house nutritionists.

    But can we assume that the feeding regimes for horses in hard work can be used for ponies by simply scaling down the recommendations according to size and weight? Should we be using a different formula for calculating the nutritional requirements of a pony in hard work? Ponies are more prone to metabolic disorders associated with feeding, such as laminitis and equine metabolic syndrome. They tend to pile on weight more easily than big horses and they are almost always ridden by children and young riders, who might be at risk if overfeeding a pony made him too hot to handle.

    Hay levels

    British scientists have just published a research paper that answers some of these questions. They took four adult ponies between 10hh and 14.2hh that were regularly used for competitions, Pony Club work and hacking, and brought them to an equine nutrition research station. Each pony was exercised every day under saddle to a level that represented quite hard work.

    For the first five days, the ponies were put on good meadow hay that equated to 2% of their body weight. Concentrates were then introduced over a two-week period until 50% of their feed was high-energy concentrate. For a five-day period, they were then carefully studied and investigated. This included collecting all of their droppings and analysing the digestibility of the feed, as well assessing their behaviour, measuring weight and checking the exact composition of the diet in the laboratory.

    Each pony was subject to several cycles of this research, using three different high-energy feeds, and also a cycle in which they were kept on hay only. All the time, they were worked hard.

    Feeding 50% of the daily diet as high-energy concentrates is a recommended practice for large horses, but was it appropriate for the ponies? The results showed that hay alone does not provide enough energy or protein to supply the needs of hard-working ponies, even if the hay is good-quality meadow hay. Feeding 50% of the daily diet as concentrates exceeded the ponies’ actual requirements, but not by much, so the scientists concluded that the recommendations for feeding used for horses can be applied to ponies.

    They were pleased to report that there appeared to be no adverse effects of such high-level concentrate feeding — as long as the pony was working hard — with no weight gain and no detrimental effects on behaviour or temperament. They do, however, issue one word of caution: the three concentrate feeds selected for the research were all relatively high in oil and therefore lower in starch, compared with some other products. High starch is known to heat up the behaviour of horses and oil is known to calm them down, so every concentrate feed might not give the same results.

    A cause of coughing — it’s in the genes

    Most horses are stabled at night, at least, at this time of year. One of the most common ailments arising from horses spending long periods indoors is the respiratory condition, recurrent airway obstruction (RAO), also known as equine asthma, heaves or chronic obstructive respiratory disease (COPD).

    In winter, there are few weeks when a horse vet doesn’t find a case of a “coughing horse” in the diary.

    Many of these are so-called “stable coughs” — an allergic reaction to dust caused by hay, straw and other dry material. Mild cases are just a persistent cough, but severely affected horses may struggle to breathe and display noisy, wheezy respiration.

    We know the cause is dust in the stable atmosphere, especially the fungal spores from poor-quality hay, but why are some horses prone to the problem and others not? We also know that a foal from a mare with RAO is more than three times more likely to develop the condition later in life than a foal from a mare with good respiratory health, which suggests a heritable predisposition.

    Scientists in Switzerland probed the genomes of RAO-affected warmbloods and compared them with unaffected horses. They identified nearly 200 horses with RAO, for which they had pedigrees going back five generations, and studied their breeding and ancestry.

    The research showed a significant correlation between differences on chromosome 13 in the affected horses compared with the others. This confirmed earlier work in which chromosome 13 was suspected of playing a role in susceptibility to RAO.

    Each chromosome has millions of “genes” on its spiral of DNA and this new study was able to identify a region of the chromosome that appears to be important. It seems this region is involved in coding for a particular protein that is connected to respiratory health.

    In the future, we might be able to screen horses to see whether they are more prone to allergic airway disease and manage them appropriately to prevent the disease appearing.

    Taking stock of stress

    A broodmare at stud must undergo some potentially stressful procedures. Research has been conducted into the stresses of transport, change of yard, the process of foaling and other elements of breeding life, but little investigation has been undertaken into the stress caused by gynaecological examination by rectal palpation.

    This is a fundamental procedure for the stud vet: the examination of the reproductive tract by inserting a hand into the rectum or scanning through the rectal wall. It is not uncommon for maiden (first-time mares to object violently.

    For the vet’s safety, most professional studs have stocks in which the mare is confined to prevent her kicking. Most mares seem to become accustomed to the procedure, however, and experienced broodmares generally stand quietly.

    Vets in South Africa wondered whether this apparent acceptance of rectal palpation is an indication that experienced mares are no longer fazed by the process, or whether they have just given up objecting.

    They took 28 mature mares, all of whom had been used for teaching and were accustomed to rectal examinations by both teaching staff and vet students. Measurements of stress were made as the mares were prepared for the session, then again during the 20-minute session of examination and for a further 70 minutes afterwards to record the return to baseline stress levels.

    The results showed an initial stress response as the rectal examination started, which settled as the exam proceeded. By the time the session ended, stress levels were almost back to the pre-examination levels.

    This suggests that even experienced stud mares are a bit stressed when the examination begins, but become less so, provided the procedure continues in a familiar way.

    An additional finding was of interest. Each mare was kept in the stocks for more than an hour to monitor her stress levels after the exam, because the scientists predicted that some settling time would be needed once the student’s arm was removed. In fact, the mares were already quite chilled out by this stage, but became more stressed by being confined. They were used to being released as soon as the examination was over, but this change in routine — keeping them shut up — was upsetting for them, emphasising the importance of providing horses with a consistent routine.

    Ref Horse & Hound; 11 January 2018