The effect of dietary rumen degradable protein content on veal calf performance

The objective of this study was to determine the undegradable dietary prote in requirements of veal calves. Two experiments were carried out with Holst ein bull calves from 3-10 days of age until slaughter at 20 weeks of age. B oth experiments were divided into starter and finishing periods. Calves wer e offered starter pellets on an ad lib. basis from seven days of age. Diets were formulated to be iso-nitrogenous and iso-caloric, and differed in und egradable dietary protein content. In Experiment 1 calves were randomly ass igned to one of three dietary treatments containing low (LD), medium (MD) o r high (HD) levels of rumen degradable protein. In Experiment 2 calves rece ived a starter diet containing either a high or a low level of rumen degrad able protein. At the end of the starter period animals from both treatment groups were re-assigned at random to finisher diets containing either low o r high rumen degradable protein levels, resulting in four treatment combina tions, viz. LL, LH, HL and HH. There were no treatment differences for feed intake, body weight gain or feed efficiency during the starter period of e ither experiment. During the finishing period (weeks 12-20) of Experiment 1 , calves receiving the LD diet had higher average daily gains than calves r eceiving the HD treatment. Feed conversion ratio for the LD treatment was a lso better than for the other two treatments. During the finishing period ( weeks 11-20) of Experiment 2 the feed conversion ratio tended (P < 0.10) to differ between treatments: feed conversion ratio for the LL and HL treatme nts was more favourable than that for the LH treatment. Feed conversion rat io for the HH treatment was intermediate, and did not differ fi om that of the LL, HL or LH treatments. The level of crude protein degradability appea rs to have no effect on calf performance during the starter period, but it may, however, be beneficial to feed finisher diets with a lower crude prote in degradability during the finisher period.