Published online by Cambridge University Press: 02 September 2010
The intake of silage, concentrates and grazed herbage, and the performance of 16 Masham ewes carrying and suckling either single or twin lambs, was measured during the last 7 weeks of pregnancy, during lactation and after weaning.
There was no difference in intake between ewes with singles or twins in pregnancy, lactation or after weaning. The metabolizable energy intakes, from silage and concentrates, of the ewes with singles and twins were 101 and 100 MJ per head per day in weeks 7 and 6 pre partum, 21·4 and 19·9 MJ in weeks 3 and 2 pre partum, and 24·4 and 23·8MJ in the 1st week of lactation. The intakes from grass and concentrates were 32·3 and 338MJ in weeks 5 and 6 of lactation for the ewes with singles and twins respectively, and 13·8 and 15 2M J from grass alone after weaning. There was no effect of ewe live weight on intake and, although the ewes with singles were producing less milk than those with twins, their intakes were similar.
The same ewes consistently ate the most feed. The overall coefficient of concordance was 05 6 and the coefficients for mid- and late-pregnancy, late pregnancy and early lactation, and early- and mid-lactation were 0·57, 0·62 and 0·66 respectively. The ewes with twins that consistently ate the most lost less weight in pregnancy, produced similar litter weights and suckled lambs that grew faster. Their levels of intake and production were high: the growth rate from 0 to 6 weeks of age of the twin lambs suckling the large-eaters was 721 g/day compared with 631 g/day for those suckling the small-eaters. During lactation the ewes with singles appeared t o consume more metabolizable energy than their maintenance, milk yield and live-weight gain requirements justified, whereas the group of smaller-eating ewes with twins put on more weight than expected from their intakes.