Choice of age of castration in grass beef production

Abstract

Beef production from grass in France is based on castrated animals. However the uncastrated male has a faster growth rate and presences leaner meat. This had led to the suggestion that young bulls could be castrated later with an increased risk of stress and disease if the animals have already reached a certain stage of development. The aim of the studies carried out in Le Pin au Haras INRA experimental farm was to understand the effects of age at castration (9 or 13 months) on grass beef production. These effects have been studied in relation to others factors during three trials : maturity of breeds, feeding level during the rearing period and slaughter age. It appears that the age at castration does not modify appreciably animal characteristics at slaughter. Many interactions during the rearing period and compensatory growth effects reduce the expected differences with castration age. However the carcases of late castrated animals seem to be leaner. Finally under working conditions the choice of age of castration (around 1 year old) seems to be defined by practicality and risk of stress for the animal.