Bases for evaluating the reproductive performance of breeding herds managed under grazing conditions

Abstract

Some factors influencing the reproductive performance of beef breeding herds managed under grazing conditions are discussed in this paper. In addition, the objectives for commercial beef herds are set and an index of reproductive performance efficiency (IER) es presented. The use of IER for comparison between different herds is considered. Total kg of calves weaned per hectare is not only dependant upon those basic resources of the farm but also on management decisions which set the stocking rate and the reproductive practices carried out in the farm. Both these factors have an overriding importance in defining the reproductive efficiency of beef breeding herds. The ultimate objetive for beef breeding herds must be minimun weight and condition of the herd through least cost feeding systems consistent with heavy calves at weaning, satisfactory cow and calf survival and unimpaired fertility. Because of pregnancy rates alone do not account for many of those factors influencing reproductive efficiency of beef herds, IER can help to compare different herds managed under different environment as well as to determine the scope improvement in that efficiency.