The effect of alternative flock replacement strategies on the lifetime productivity of the ewe

Extract

Sheep production economics are dominated by the overhead costs of maintaining the ewe and it lias been suggested that breeding from ewe lambs is an important means of increasing lifetime productivity and thus flock returns. Numerous trials have shown that ewe lambs can be successfully mated providing the animals achieve a threshold bodyweight within the breeding season. There is evidence to suggest that the subsequent performance of the ewe lamb is not impaired and may even be improved providing the nutritional management is adequate to sustain foetal and maternal tissue growth in pregnancy; the rearing burden and duration of lactation is restricted. A study of commercial flock records reveals great variation in performance and many doubt the validity of the practice on the basis of management difficulties and subsequent production. This trial looks at the effect of alternative management treatments on current and subsequent performance of ewe lambs.