Published online by Cambridge University Press: 02 September 2010
The performance of 32 Cambridge (C) and Suffolk × Cambridge (S × C) twin and triplet rearing ewes and their progeny was investigated from lambing until the lambs reached slaughter weight. The ewes and lambs were housed and penned in individual family groups until 35 days after lambing. From 7 to 35 days the effect of rearing type was studied in combination with feeding the ewes a complete diet containing either 250 (diet 250) or 400 (diet 400) g milled hay per kg. After 35 days ewes and lambs grazed pasture. Ewes suckling triplets produced slightly more milk at 20 days 4·3 v. 4·1 (s.e.d. 0·20) kg/day and significantly more at 30 days 4·1 v. 3·7 (s.e.d. 0·18) kg/day, but consumed similar amounts of dry matter (3·9 kg/day) and so tended to lose more body condition. The latter was also a feature of ewes given diet 400 which produced similar milk yields but had lower complete diet intakes than those on diet 250. S × C had higher yields than C ewes.
Triplet lambs grew faster than twins 361 v. 290 (s.e.d. 9·0) g/day to 35 days but during the outdoor period triplet males but not females grew as fast as their twin counterparts 337 v. 317 for males and 269 v. 302 for females (s.e.d. 12·7) g/day. A selection of male twin and triplet lambs was slaughtered within the range 39 to 42 kg when 102 and 105 days old respectively. Triplet lambs had a lower killing-out proportion 0·458 v. 0·477 (s.e.d. 0·0085) and hence carcass weight but all carcasses qualified for Meat and Livestock Commission certification.