Studies of autumn calving suckler cows, bulls at pasture and winter grazing.

Abstract

Most beef and dairy cows are spring calving leading to distinct seasonality of supply. Calving a proportion of the beef herd in the autumn would lead to a more uniform annual supply of cattle for slaughter and potentially increase the proportion of grazed grass in the diet of the suckler progeny. Autumn calving sucklers also facilitate the use of AI, which should enhance the product quality. This project aimed to address the technical aspects of autumn calving sucklers, which differ from those of spring calvers. The currently available international energy models were evaluated for autumn calving lactating suckler cows using the type of cow typically found in Irish suckler herds (Experiment 1). The winter accommodation of the suckler cow and calf unit and its impact on cow reproductive performance was evaluated (Experiment 2). The final part of the project evolved into component studies to determine the effect of supplementary feed on the performance of grazing bulls (Experiment 3), and the consequences of weanling cattle grazing pasture in winter as an alternative to housing them in winter (Experiments 4 to 7).