Selecting sheep for visual traits results in a higher incidence of lambing difficulties, compared with selection based on performance traits.

A study of two Scottish Blackface flocks over four years compared lambing difficulties in ewes selected for either visual traits, improved carcass and maternal traits or selected on average performance index, said Nicola Lambe of SAC.

“Ewes selected for visual traits had the highest probability of lambing difficulty, with those selected for improved carcass and maternal traits having the lowest incidence of lambing problems.”

Further analysis revealed that lambing difficulties were significantly affected by ewe sire and lamb sire, ewe age, lamb sex and ewe pre-mating weight.