The performance of Jersey cows and cows of larger dairy breeds on two complete diets with different roughage contents

Abstract

A group of 38 Jersey cows and a control group of 12 Holstein Friesian (HF), 12 Dutch Friesian (DF) and 10 Dutch Red and White (DRW) cows were fed, after their third calving, a complete diet of roughage (R) or a complete diet of the same roughage with 50% concentrates on a dry matter basis (C). Body weight, milk production and feed intake were recorded during the first 39 weeks of lactation. All cows had already participated in this experiment in their first lactation on the same diets. For the characteristics studied, the differences between the breeds on both diets were not equal. However, only for fat percentage was a significant breed × diet interaction found. Mean differences between the Jersey and the HF + DF + DRW group for the C diet and for the R diet (in parentheses) were −936 (−748) kVEM (1 kVEM=6.9 MJ NE) for energy intake; −2560 (−1707) kg for milk yield; +2.82 (+2.38) for fat percentage; +0.83 (+0.77) for protein percentage; +3 (+23) kg for fat yield; −55 (−26) kg for protein yield; −199 (−216) kg for average body weight; −57 (−27) kg for weight gain. From first to third lactation, energy intake and milk yield for the Jerseys and the HF + DF + DRW increased in the C diet groups by 25 and 24%, respectively, and in the R diet groups by 48 and 51%, respectively. The biological efficiency for milk production (energy in milk divided by net energy in feed) was 57% for the Jersey group on the C diet, 69% for the Jersey group on the R diet, 56% for the HF + DF + DRW group on the C diet and 61% for the HF + DF + DRW group on the R diet.