Exercise response, metabolism at rest and digestibility in athletic horses fed high-fat oats

Abstract

Reason for performing study: High starch intakes increase the risk for metabolic disorders and therefore alternative feedstuffs are of interest. High-fat oat varieties have a lower starch and higher energy content than regular oats and may therefore be useful in this context.

Hypothesis: Feeding high fat oats causes no adverse effects on the response to exercise and that the total amount of oats offered could be reduced compared to feeding with regular oats.

Methods: Twelve Standardbred trotters were fed regular oats (diet C), high-fat oats (F), and a mixture (50:50) of C and F (M), together with haylage (30:70), in a Latin square design trial. High-fat oats replaced regular oats in a 0.9 to 1.0 ratio in diets F and M. On Day 18 in each 21 day experimental period, horses were subjected to a standardised near-maximal treadmill exercise test with collection of blood samples and muscle biopsies before and after exercise. This was followed by a 3 day period of total collection of faeces and urine.

Results: There were no significant effects of dietary treatments on bodyweight, heart rate, plasma lactate and glucose, or on muscle glycogen and lactate concentrations following exercise. However, plasma insulin was reduced during exercise on diets F and M compared to diet C. The total tract digestibility of dry matter, fat, protein, NDF and organic matter were higher for diet F than for diet C.

Conclusion: High-fat oats can replace regular oats in the diet of athletic horses without any adverse effects on metabolism and exercise response.

Potential relevance: Due to the high energy content and a high digestibility of dietary components in high-fat oats the daily allowance of oats can be reduced and thus the intake of starch.