The energy requirement of young female cattle. 1. Research overview and body weight development of the animals

Abstract

In the period of 1975-1982 6 experiments with young female cattle of various rearing intensities were carried out. The respiration trial technique for the measuring of energy and protein metabolization in connection with the registration of a number of rumen physiologic data were applied together with comparative studies of the digestibility and the rumen fermentation of the rations used with young cattle and with fully grown sheep. The extent of the experiment was characterized by 695 metabolism periods in calves and young cattle as well as by 149 comparative studies of the digestibility and the rumen metabolism of the fully grown sheep. The results ascertained are the basis of the derivation of the energy requirement for the rearing of young female cattle according to factorial criteria. This first out of six papers on these experiments comprises an outline of the experiment arrangement, the material and the methods as well as of the live weight development of the animals. In four of the six experiments there was a continuous monthly registration of the measured values over the complete period of the rearing of the weaned calves up to their calving with four animals each under conditions of extremely high (experiment 1), medium (experiments 5 and 6) and low (experiment 3) rearing intensity. Experiments 2 and 4 provide additional information on rearing periods under special consideration of the gestation period. In experiment 1 the cows were not milked after the first calving, and measuring was continued to the second calving of the animals.