Intake studies in grazing beef and dairy cattle

Abstract

In recent years there has been a growing demand for increased levels of efficiency in the pastoral industry. To achieve this the efficiency of conversion of the individual animal must be measured by equating its level of intake to its level of production. The need for an accurate estimate of the intake of pasture by the grazing animal is therefore vital. Much information is already available for sheep and dairy cattle but there remains a dearth of knowledge in respect to beef cattle. Many workers have revealed intakes of cattle which relate to particular animals and feeding conditions. These results have proved invaluable, but, when used to predict the animal’s feed requirements (particularly for maintenance) have led to values inconsistent with those of other workers. In New Zealand current interest is focused upon the dairy animal’s potential when used for beef production. Such “dairy-beef” animals include the Friesian and Charolais-Friesian cross, rated highly for their rapid rate of growth and high lean meat carcasses. The purpose of this trial was to evaluate the intake and performance of various breeds of “dairy-beef” animals. In addition, various breeds of dairy cows were studied under similar grazing conditions to provide a standard of reference to previous intake estimates. The important aspect of the trail was the estimation of intake and the literature on the various methods of intake determination was reviewed. Under New Zealand grazing conditions the Chromic oxide – faecal Nitrogen technique was found most suitable and subsequently used in this trial.