Feed Form Affects Growth and Stomach Ulcers in Yearling Horses

Fourteen yearling standardbred horses were used to test the hypothesis that hay and grain fed as a complete total mixed ration (TMR) cube diet (C) would result in greater average daily gain (ADG), feed efficiency (gain to feed ratio, G/F) and apparent digestibility in horses on the TMR diet compared to horses fed the same weight and proportion of hay cubes and grain fed separately (diet HG). Both diets consisted of 75% forage and 25% ground oats. The forage in both the plain hay cubes and the complete cubes was 80% alfalfa and 20% endophyte-free tall fescue. An additional hypothesis that stomach ulceration would not differ between horses fed either of the two diet treatments was also tested by comparing upper gastric endoscopies before and after 70 days of feeding the experimental diets. Horses fed diet C had greater ADG (P 0.065) but showed a trend to be higher in the horses consuming diet C. Apparent digestibility of dry matter and crude protein was not different between the diet treatments, and no major gastric ulceration was found in horses consuming either diet treatment. The results of this study found that a complete cubed diet of 75% hay and 25% oats did not cause stomach ulceration while achieving an acceptable growth rate in yearling horses.