Effects of Number of Lambs Suckled a N D S U P P L E M E N T a L Protein Source on Lactating Ewe Performance 1'2

Effects of number of lambs suckled and supplemental protein source on ewe performance were determined. Lactat ion performance of ewes nursing twin or triplet lambs was compared in Exp. 1 and 2. In Exp. 1, ewes giving birth to and nursing triplets produced 21% (P<.05) more milk/unit metabolic body weight, were 10% more efficient in the conversion o f feed to milk and produced 26% (P<.05) more kg of lamb/ewe on d 42 of lactation than did ewes giving birth to and nursing twins. In Exp. 2, lactat ion performance of ewes giving birth to triplets and rearing only two lambs was compared with performance of ewes giving birth to triplets and rearing three lambs. Ewes rearing three Iambs produced 28% (P<.08) more milk and were 26% (P<.05) more efficient in converting feed to milk than were those rearing two lambs. This suggests that direct nursing stimulation of the mammary gland is responsible for the improvement in milk production observed when ewes nurse additional lambs. The efficacy of slowly degradable protein sources for improved lactation was studied in Exp. 3 and 4. When blood meal was fed to twin-rearing ewes at 3.30% of the diet (25% of total dietary protein), milk production was greater (3,176 vs. 2,506 g/d, P<.05) and efficiency of milk production was greater (1.05 vs