The present work was carried out from 07/14 to 10/06/92, at the Department of Animal Science "Universidade Federal de Santa Maria, RS, Brazil". The purpose was to evaluate the effect of two protein sources (soybean grain versus soybean meal) upon the performance of confined beef calves. The experimental period of 84 days, was subdivided into four periods of 21 days. Twenty noncastrated Nellore x Charolais crossbred calves, with initial average weight of 160kg and average age of 7 months, were used. The calves were distributed in four paddocks of 800m² each. The animals were submitted to the following treatments: T1 - sorghum silage plus concentrate (soybean meal + corn + mineral mixture), and T2 - sorghum silage plus concentrate (soybean grain + corn + mineral mixture). The soybean grain was used in natura and triturated at the moment the ration was being prepared. The proportions of roughage : concentrate used in the experiment were: 75.04 : 24.96; 71.04 : 28.96; 67.53 : 32.47 and 62.72 : 37.28, in the 1st, 2nd, 3rd and 4th periods, respectively. The diets were isoprotein, with an average content of crude protein of 12.5% (in DM). The mean of the four periods for average daily weight gain (kg/an/day), dry matter consumption (kg/an/day) and feed conversion were 1.114kg; 6.03kg and 5.55 for T1 and .975kg, 5.69kg and 5.91 for T2 respectively. The animals submitted to T1 showed a better average daily weight gain (P< .05). The analysis of variance showed significant difference between the treatments for dry matter consumption (kg/an/day). However, when the consumption of dry matter was analysed per 100kg of live weight and per unity of metabolic size, there was no significant difference between T1 and T2 (P> .05). Concerning feed conversion, there was no significant difference between the treatments (P> .05).
calves; confinement; soybean grain; soybean meal
