ChileanJAR

Thirty Holstein cows with 2 - 3 weeks of lactation were assigned in a randomized complete block design to three treatments: Concentrate I.Corn - rape seed meal - urea; Concentrate II.Corn - rape seed meal - fish meal; and Concentrate III. Oats - rape seed meal - urea. The concentrates contained 16.9% crude protein. Concentrates I and III included 1.5% urea while number II had no urea, it was replaced by fish meal. Concentrates I and II contained 75 and 77.5% ground comn and number III had 75% ground oats. The cows received 6 kg concentrate/day and corn silage ad libitum plus 5 kg red dover hay. During the 67 days tnial, the animals were maintained in three groups, according to treatment, and housed outdoors, with access to a covered feed bunk with a concrete platform. MiIk production adjusted by covariance was 20.2; 19.9 and 18.3 kg/day, forthe treatments I, II and III, respectively. Concentrate III which contained oats produced significantly (P < 0.05) Iess milk than the two treatments that included corn in the concentrate. Protein solubility had no significant (P > 0.05) effect on milk production. Milk fat content and liveweight gains were not affected (P > 0.05). Total dry matter intakes were similar, with a trend to a lower feed efficiency for the treatment III thai included oats in the concentrate.