KER Answer Exchange – Yearling Growth

From KER:

In last week’s Kentucky Equine Research Answer Exchange, their nutritionist provides a recommendation for a horse owner looking to help a yearling gelding grow without risking joint problems.

Question

I have a yearling gelding that I handle daily but ask nothing from in the way of exercise. He weighs 630 lb (290 kg) and is thin, probably a body condition score of 4. He is stalled 8 hours of the day and turned out the remainder of the time. He has no health issues, but I’d like to challenge his growth a bit and get him to gain some weight. He’s always grown fairly evenly—front and back—though now he seems to be especially rump-high. He’s currently getting 12 lb (5.5 kg) of sweet feed a day split into two meals, free-choice grass hay, alfalfa pellets, and salt. He doesn’t always eat all of the sweet feed. How can I fiddle with his diet to increase weight and height without risking joint problems?

 

Answer

Properly nourished young horses will often experience an ebb and flow to growth.

His current “lightness” of weight may be due to a growth spurt. Visibility of ribs in a young horse is not considered a true indicator of being underconditioned as it is with older horses. Ideally, the ribcage should have fat covering the upper one-third to one-half of the ribcage. Greater fat coverage may indicate the horse is too heavy.

Figuring out just how much grain the yearling is eating on a daily basis is difficult, as you indicate he is offered 12 lb (5.5 kg) but often doesn’t consume the full amount. Tracking how much he leaves in the feed tub after each meal over a week or two would have given me a better idea of how much he is actually consuming. Inappetence can lead to insufficient calorie consumption, and habitual lack of intake could affect growth rate. Smooth, moderate growth allows horses to reach their genetic potential and helps ward off development orthopedic conditions, such as physitis and osteochondritis dissecans.

Concentrate meal size for yearlings should be kept below 5 lb (2.3 kg). It would be best to choose a feed specifically formulated for young, growing horses, and most of these feeds are designed to keep meal size below 5 lb (2.3 kg). To boost the caloric content, you may want to consider using stabilized rice bran, a high-fat feedstuff that dovetails nicely with a balanced ration.

Dietary fat is considered a safer source of calories than starch and sugar. Fat is highly digestible, reduces the risk of digestive upset, and produces a mild glycemic response after feeding when compared to starch and sugar. Diets of young horses should have a significant portion of calories coming from good-quality forage, a well-fortified young horse feed, and additional fat, if needed.

By 12 months of age, about 60% of mature weight has be attained and, at 24 months, horses are approximately 95% of their mature weight. Daily weight gain will decline at a constant rate from about four months of age to reach a low at 10 to 11 months of age, coinciding with the time of reduced pasture growth and availability in the winter. Growth rates are observed to increase in the first spring of a horse’s life, which is possibly a function of increased pasture growth and onset of puberty.

Regular assessment of your yearling’s body condition and weight is important to track his growth and to identify if and when dietary intervention is needed to maintain even growth.

Kentucky Equine Research (KER) has collected and collated growth data for thousands of young horses all over the world. Using this information, the company created a program called Gro-Trac that helps breeders compare the growth of their young horses with those of similar age and breed. Learn more about Gro-Trac.