The nutrition of the early-weaned calf V. The effect of protein quality, antibiotics and level of feeding on growth and feed conversion

Abstract

SUMMARY1. A 2×2×2 factorial experiment was carried out with 8 blocks of 8 early-weaned Friesian male calves on the 8 treatment combinations of the following factors: (A) groundnut meal versus white-fish meal as the major protein source; (B) presence versus absence of antibiotic and (C) restricted versus ad lib. feeding. The experiment was conducted over the live-weight range 55–90 kg.2. The inclusion of fish meal rather than groundnut meal in the diet resulted in highly significant increases in both rate of gain and feed conversion efficiency (P < 0·001). This effect was most apparent at the higher level of feed intake.3. The addition of antibiotic to the diet increased rate of gain (P < 0·001) and improved feed conversion ratio (P <0·01). Feed intake was increased slightly but non-significantly (P <0.1) on the ad lib. feeding level as a result of antibiotic supplementation.4. Feed conversion ratio was lower and feed intake and rate of gain were higher on ad lib. than on restricted feed (P < 0·001 in each instance).5. There was a significant (P < 0·05) level of feeding × antibiotic interaction, indicating that the difference between restricted and ad lib. feeding was greater in the presence than in the absence of antibiotic. No other significant interactions were observed.6. The use of fish meal in preference to groundnut meal is shown to be justified on economic grounds.