Fattening of Polish Lowland lambs on diets with different energy and protein levels

In an experiment conducted on 96 male lambs (3 groups of 32) fattened from 19 to 39 kg on diets containing various levels of crude protein (16 vs 14% in DM) and metabolisable energy (12.4 vs 12.7 MJ/kg DM) no significant differences in daily liveweight gain were noted (272 to 279 g). Feed utilisation was similar in all groups. A tendency (P>0.05) towards somewhat better protein utilisation (586 vs 674 g/kg) from isoenergetic rations was observed in lambs fed rations containing 14% CP than in those receiving 16% CP. Slaughter performance, morphological and chemical composition of the lambs' empty body weight, protein (18.3-19.8%) and fat (17.6-21.4%) deposition in empty body gain did not differ significantly among groups. Differentiating the level of protein (103-163 g/kg DM) in concentrates used to feed suckling lambs had no effect on liveweight gain during fattening (262-288 g daily).