Effect on production records of sex of lamb, twinning, and dam's age in a grassland flock

Abstract

The effects of sex, twinning and age of ewe on birth weight, weaning weight and fertility have been studied in 5 years' records of a small grassland flock of Wiltshire × Blackface crossbred ewes with the object of providing provisional correction factors for these variables in recorded flocks under similar management. All these variables produced large effects in the flock studied. On birth weight these were; sex, 0·6 lb.; twinning, 2·1 lb.; hogg's lamb, 2·3 lb. The corresponding adjustments for weaning weight were 7 lb., 14 lb., and 11 lb. Ewes first bred as hoggs subsequently performed well.