Relationship between practices and troop renewal rates in Limousin beef cattle herds

Abstract

Herd renewal practices were analysed on 20 Limousin beef cattle farms for which the rates of annual renewal vary from 15 to 39%. Culling practices were studied from culling causes, types of culling (involuntary, systematic or optional) and by identifying the different sampling methods according to cow age group. The characterisation of heifer recruiting practices was based on periods of selection of the young and on the severeness of these selections. Three types of renewal practices of herd composition were identified : 1) culling and recruitment performed in part on the same individuals, young cows from 3 to 4 years of age (high renewal rate), 2) farms where culling is essentially systematic and concerns older cows (lowest renewal rate), 3) intermediary cases where an equilibrium has been established between relatively early recruitment of the young and moderate mobilisation of optional culling criteria that concern all age groups of cows (varying renewal rates).

The notion of standard culling (elimination of the oldest cows that are unsuitable for production) and renewal (early choice of heifers issued from planned matings) were insufficient to describe the breeding practices of farmers who adopt high renewal rates.