[Effect of growth hormone on meat production in heifers]

Short-term treatment of bovines with growth hormone (GH) has shown that GH increases nitrogen balance. In the present experiment we studied the effects of exogenous GH on weight gain, feed efficiency, carcass grade and meat quality. Twenty heifers of the Belgian White Blue breed were used. After an 8-week pre-experimental period, during which we recorded individual growth rates, the animals were allotted to two groups for 18 weeks; one group (T) received daily 50 micrograms of pituitary GH per kg of liveweight, whereas the other group (C) was given a placebo. Long-term treatment with GH induced weight gain (C: 117.1 +/- 25.5 kg; T: 144.6 +/- 23.7 kg; 23.5% increase, P less than 0.05) and increased feed efficiency (C: 10.34 +/- 2.04 kg DM/kg weight gain; T: 8.24 +/- 1.03 kg DM/kg weight gain). Digestibility of diet dry matter was identical in both groups (C: 60.1 +/- 2.7%; T: 59.8 +/- 2.4%). There were no difference in the classification of group C and T carcasses according to the EUROP pattern and after monocostal segment dissection (7th rib). Furthermore, the meat analysis of the two groups was identical with respect to protein, fat and collagen content. This was also true for tenderness, pH and juice loss after cooking. We concluded that stimulation of bovine weight gain by GH was significant and efficient while meat quality and carcass grade were not improved.