Effects of nutrition in late pregnancy on subsequent milk production in Ewes

Abstract

SUMMARY1. Scottish Half-bred ewes carrying twin foetuses were fed individually to make live-weight gains in the last six weeks of pregnancy of (1) 20%, (2) 10% and (3) 0% of their live weight in week 14 of pregnancy. In lactation the ewes were fed ad libitum. The lambs were removed 12 to 16 hr after parturition and the ewes were machine-milked twice daily for the first six weeks of lactation.2. Total birth weights per ewe of twin lambs from the treatments were (1) 10·10 kg, (2) 9·44 kg and (3) 8·18 kg and differed significantly.3. The level and pattern of voluntary intake in lactation did not differ significantly between the treatments. Total dry-matter intakes in the six weeks of lactation were (1) 121·9 kg (2) 105·9 kg and (3) 109·5 kg.4. The pregnancy treatments affected the level of milk production and the shape of lactation curves. The total yields in the first six weeks of lactation were (1) 58·8 kg, (2) 43·5 kg and (3) 26·9 kg. Higher contents of fat and protein and the lower content of lactose in the milk from treatment-3 ewes on days 1 and 3 of lactation indicated a slower onset of lactation in these ewes. Between days 7 and 35 of lactation the contents of fat and SNF were lowest on treatment 3 but the differences were not significant.5. The live-weight changes in lactation, which were in inverse order to the gains in late pregnancy, were (1) 3·4 kg, (2) 5·5 kg and (3) 9·5 kg.