Performance, longevity and financial impacts of removing productive ewes early from mountain flocks

Traditionally in the UK many breeding ewes are sold from mountain farms, after their fourth or fifth annual crop of lambs, to lower altitude upland farms where they are mated with longwool breeds to produce more prolific crossbredewes. This is a key element of the UK stratified sheep industry. However culling mountain ewes at a fixed age from the flock limits longevity and may not be in the financial interests of the farm. To understand whether culling on agefrom a mountain farm still occurs, a questionnaire was carried out with 115 farmers. Results showed that there was a difference (P<0.05) between system type (mountain, upland and lowland) for those flocks where ewes were culledon age with the largest majority being mountain (55%), then upland (41%) and finally lowland (29%). However not all mountain farms culled on age which could indicate a change in culling practices from our previous understanding.Actual results from a research mountain flock was used to model the financial implications of culling based on age. Results showed that a flock where productive ewes were allowed to remain after their fourth lamb crop had thepotential for a greater margin compared to a flock that culled ewes after their fourth crop. This was largely a result of more replacement ewe lambs being sold and reduced costs for the first unproductive year before lambing at two years old. However, financial viability and sensitivity were highly dependent upon relative sale value of retained ewes, and input costs for replacement females up until their first lamb crop. Furthermore, performance of older ewes (those aged 5.5 years old or older at the start of the production year) was compared to all other ages. Results showed that performance was similar between older ewes and all other age groups of ewes, in terms of: survival, number of lambs born and weaned, and weight of lambs weaned. Therefore, culling practices in the UK mountain flocks appear to be changing. Retaining older ewes within the flock could provide potential benefits as they are able to perform as well as younger ewes and could increase overall longevity for these flocks. This also brings potentially greater profits and resilience for mountain farmers