Performance and financial returns of two Romney flocks sired by Waihora or Commercial rams

Abstract

Abstract From the same base population of Romney ewes in 1971, two flocks were generated by mating and subsequentl y backcrossing ewes to either average-merit rams from the Waihora Romney Breeding Scheme of the Department of Lands and Survey (Rotorua), or to rams from commercial sources normally available to the Department. The Waihora and Commercial flocks were managed separately only during mating and from lambing to tailing. Physical and financial records of the two flocks over the period 1979-85 were compared. Mean litter size (lambs born per 100 ewes lambing) was 121.9% for Waihora ewes and 110.2% for Commercial ewes (P < 0.01). Flock differences in ewe fertility and lamb survival tended to be small, but performance levels were higher in the Waihora flock. Mean net reproductive rates (lambs weaned per 100 ewes present at lambing) for the Waihora and Commercial flocks were 105.2 and 92.3%, respectively (P < 0.01). Over all years combined, 59.1 % of wether lambs drafted for slaughter were from the Waih...