feeding weanling horses
Answers from Pat Harris MA, VetMB, PhD, Dipl. ECVCN, VetMB , MRCVS, of WALTHAM Centre for Pet Nutrition and MARS Horsecare, based in the U.K.; Peter Huntington, BVSc, MANZCVSc, director of nutrition at the Australasian branch of Kentucky Equine Research (KER), in Victoria, Australia; and Laurie Lawrence, PhD, professor of equine nutrition at the University of Kentucky, in Lexington, given during a roundtable at the KER Conference 2018, held Oct. 29-30 in Lexington.

Lawrence: Nutrients are tied to the composition of weight gain. It’s a continuum, everyone must make a decision based on where their horses are along that continuum. If they have enough young horses, a manager would group them by age. In those cases you can be a little more strategic in how you feed them specifically.

We have good forage here in Central Kentucky in the fall, and the fall is usually mild, so the horses grow nicely. And then if we get a really severe winter, a lot of them will slow down, and then they oftentimes will take off growth-wise in the spring if they’ve gotten too far behind.

Nutritionists who consult in Central Kentucky say to be careful in times of very cold weather so young horses don’t get behind, because once they get behind, the next thing that will happen is they’ll have that compensatory growth.

All things are important in terms of preventing developmental orthopedic disease, but moderate, steady growth with a balanced diet and consistent exercise is probably the best way we can minimize risk–at least that’s my opinion. Here’s a way to think about it: How can we minimize risk of developmental orthopedic disease through our management practices? Nutrition is a management tool that we can use to regulate growth rate.

Harris: One minor thing to remember is the horses’ sex, because there’s some work to suggest that colts may be more active than fillies and, thus, need more calories. Also remember pasture management; what you need to feed these horses in addition to the grass depends on the quantity and quality of that grass.

Huntington: Monitor growth rate, and if you’ve got measurements of growth rate, with weight, then you can be more precise in selecting your ration. Growth rates generally decline as the weanling gets older, but there is also an influence of season, with growth slowing down in winter but then picking up in spring, when the weather and grass quality and quantity improves. Use of the KER software GroTrac will allow you to compare the size, weight and growth rate of a young horse with a reference population of the same ages, sex, and breed.

A lot of it is how much they’ll eat and how active they are in the field. The fillies stand around waiting for the feed truck to arrive, and the colts are out there fighting with each other.