The Equine Science Society recently held their symposium, and as usual, there was an excellent assortment of equine research studies in areas of nutrition, exercise physiology, reproduction, genetics, production and management, and teaching and learning. In the next few months I’ll post some summaries, but the entire journal is available here.
I’ll start with one of my own studies: Feeding practices and nutrient intakes among elite show jumpers.
In this study, a total of 34 horses competing at the 1.5 m level and higher were evaluated to determine nutrient intakes and feeding practices among this elite-level of show jumpers. Working with the owner, rider, manager or head groom, I obtained information about hay intake (weight, type), concentrates (weights and types of all fed), supplements, etc., information about nutrition related issues, and basic information about the horses themselves (age, weight estimates, etc.).
Almost all of the horses were fed the same hay that was locally sourced by the facility, and as it turned out, it was relatively low in protein and phosphorus. The results found that almost all horses were fed an electrolyte source (which is great because it was the summer and warm out!), with most horses also receiving oral joint supplements or having joints injected, and having been administered Gastroguard within the week of the competition.
Horses were offered an average of 11 kg hay and 4 kg grain, which is fairly similar to diets of other elite sport horses (e.g. eventers). The calculated energy intake wound up being close to the National Research Council’s (NRC) Nutrient Requirements of Horses (2007) requirements for horses at “intense” work, at about 33 mcal/day (for an average 530 kg horse). Protein offered averaged 1,055 g per day (2 g/kg body weight), which is similar to requirements for a horse in intense work. Calcium in the diet met 205% of the NRC requirements (twice as much as needed, though excess calcium can be excreted by the kidneys). On average, the dietary phosphorus that was offered met only 87% NRC requirements, with 22 of 34 horses receiving less phosphorus than required.
No deficiency symptoms were noted, and therefore the NRC requirement may in fact be too high, or horses had been previously fed sufficient dietary phosphorus and one week of low phosphorus intake was not enough to pose problems.
It is not uncommon for horses to arrive at show facilities without bringing their own hay or feed due to travel constraints or international rules. This poses two important challenges to the nutritional health of the horse:
1. We know that sudden changes in diet can increase the risk of colic. Horses that may be arriving after long distances, or by air travel, may arrive in a new location and suddenly be fed new hay (and perhaps also new grain). While this did not appear to be a concern with this group of horses, other horses may be more sensitive to such changes and owners should aim to make any dietary changes – even to different sources of hay – as slowly as possible.
2. Nutritional variation of local feeds (hay and grain) should be accounted for. When traveling and competing all season, there may be many differences in the diets of your horses that could result in deficiencies. Horse owners should be pragmatic and request hay analyses from facilities that provide their own hay. They should work with their nutritionist or feed company representative to ensure that their horses’ diets still meet nutritional requirements, with ever-changing schedules, locations, and feeds available.