Abstract 460

Thomas,-VM; Katz,-RJ; Auld,-DL; Peterson,-CL

Univ. Idaho, Moscow, ID 83843, USA.

Animal-Feed-Science-and-Technology. 1984, 11: 4, 269-277; 15 ref.

Two metabolism studies and one growth trial were conducted to evaluate mechanically extracted rape (RSM) and safflower (SM) oilseed meals as protein supplements for growing lambs. Fifteen wether lambs were allotted randomly to one of five treatment groups in each metabolism study. In both studies, treatments consisted of a cottonseed oilmeal (CSM) positive control, a urea (U) negative control and 3 test diets in which RSM or SM replaced 33, 66 or 100% (RSM) or 25, 50 and 75% (SM) of the CSM protein. In the growth trial, 72 ewe lambs (initial weight, 29 kg) were randomly allotted to one of 4 dietary treatments in which U, SM and RSM replaced all the CSM protein in a pelleted 14.0%-crude protein diet. In both metabolism studies, the RSM and SM diets had significantly higher ether extract digestibility than the CSM diets. In the first trial, lambs fed on the U diet retained less (P<0.05) absorbed N than those fed on the CSM diet. In the second trial, there was no difference in N balance between treatment groups. The U pellet in the second metabolism study had a higher DM and gross energy digestibility than the CSM or SM pellets. Lambs fed on the CSM, U and SM pellets grew significantly faster than those fed on the RSM pellets. Lambs fed on the U pellets consumed significantly more DM than those fed on CSM or RSM pellets. These results suggest that U, CSM and mechanically extracted SM in a high-grain pellet are satisfactory sources of supplemental N for growing-finishing ewe lambs. It appears that the high glucosinolate concentration of RSM limits the amount that can be included in diets given to growing-finishing ewe lambs.