Factors affecting production records of lambs from a flock of East African Blackheaded sheep

Abstract

1. The effects of age of ewe, and year, sex and type of birth of lambs on lamb weights between birth and weaning were measured and appropriate correction factors estimated in a flock of East African Blackheaded sheep maintained over an 11-year period in Western Uganda. These correction factors were then used to examine the effects of a long dry season at different stages of lamb growth.2. On birth weights the effects of sex ranged from 0-25 lb. to 0-40 lb.; twinning 1-0 lb.; gimmer's lamb 0-5 lb. On 2-month weights the corresponding adjustments were 0-2 lb.-l-4 lb.; 5-1 lb.; 1-7 lb. On weaning weights 0-3 lb.-2-9 lb.; 6-0 lb.; 2-6 lb.3. A long dry season during late pregnancy did not appear to affect lamb birth-weights and a dry season between 2 months and 5 months of age did not affect lamb weaning weights. However a dry season during the main suckling period from birth to 2 months of age significantly lowered lamb weights at 2 months of age.

The effect of year, suckling, dry season and type of dam (ewe or gimmer) on milk production in East African Blackheaded sheep as measured by lamb growth

“…The data from 1962 were not used, as no long dry spell occurred in that year. Trail & Sacker (1966), had previously noted that the 8-week weights of lambs suckled under wholly dry conditions were significantly lower than the weights of lambs suckled during the remainder of the year.…”

“…The data came from the flock of East African Blackheaded sheep previously described (Trail & Sacker, 1966). It was considered that in this flock, growth to 8 weeks of age was almost entirely dependent on milk from the ewe.…”