The effects of the timing of management actions on the performance of a grassland sheep flock

Abstract

SummaryA production system is defined which involves the production of lambs from crossbred ewes kept in a cool, temperate grassland environment at an altitude of 250–300 m. Within the production system, an investigation was carried out on the effect of the timing of weaning, pre-mating treatment (flushing) and concentrate feeding before lambing in a flock of 180 Border Leicester (♂) × Scottish Blackface (♀) ewes maintained for a production span of four lamb crops. Weaning treatment had no significant effects on changes in live weight or body condition score. Pre-mating treatment affected live weight and condition at mating. It did not affect the number of lambs born but had a significant effect on the subsequent birth weight of twin lambs in the 1st year it was applied but not thereafter. The timing of introduction and total quantity of concentrate feed affected the birth weight of lambs from ewes at their first lambing (24 months old) but not subsequently. There were no long-term effects of treatment on ewe survival or on the production characters measured. The results are discussed in relation to the seasonal patterns of grass supply and the normal limits of commercial practice. In this study, when grass and forage were in reasonable supply, pre-mating management and concentrate feeding were not critical to ewe performance. Only in circumstances of an unusual grass shortage and also in young ewes did these factors have significant effects on performance.