Effect of varying energy to protein ratio in creep feed and total mixed ration on growth performance and carcass quality of Boer goats

This study was conducted to investigate the effect of dietary energy-to-protein ratios on the growth performance of Boer kids at pre- and post-weaning until finishing stage. The first trial involved 24 Boer kids of one months of age, which were randomly divided into four treatment groups, with each group consisting of three females and three males. The animals were fed with formulated creep feeds with varying metabolizable energy (ME) (MJ/kg DM) and crude protein (CP, %) contents as follows: 10 MJ ME/kg to 17% CP (Group 1, control), 10 MJ ME/kg to 18% CP (Group 2), 10 MJ ME/kg to 18% CP (Group 3) and 12 MJ ME/kg to 22% CP (Group 4). Throughout 67 days of the trial period, feed intake was found to be more in Group 3 (P < 0.05) compared to other groups. Dry matter intake (DMI) reduced in Group 4 when energy-to-protein ratio was increased. No significant difference (P > 0.05) were observed in live weight gain (LWG) and body condition score (BCS) between treatments. LWG for Groups 2 and 3 were found to be higher than the other groups. The feed conversion ratio (FCR) for Groups 1, 2, 3 and 4 were 2.21: 1, 2.50: 1, 3.57: 1 and 4.65: 1, respectively. The animals from the same group were used in the second trial after they were weaned. These animals were divided into four groups and fed with total mix ration (TMR) that was isocaloric formulated (10 MJ ME/kg DM), but varying in CP namely 13%, 14%, 16% and 18% which were fed to Groups 1, 2 (control group), 3 and 4 respectively. Throughout 168 days feeding period, no differences (P > 0.05) were observed between groups in DMI, LWG, FCR and body condition score. The digestibility of nutrients was not significant between treatments (P > 0.05) and was not influenced by the dietary energy to-protein ratio. The control group produced the highest dressing percentage (55.3%). Ration that contained energy of 10 MJ ME/kg and 18% CP (Group 4) increased meat deposition in the carcass (62.9%) with the lowest fat deposition (15.4%) as compared to other treatment groups. Supplying dietary CP > 16% was not beneficial in terms of bone growth. The results from this study suggested that dietary formulation that contained 10 MJ ME/kg to 17% CP was beneficial to Boer goat kids at the pre-weaning stage based on LWG, body measurement, BCS and FCR while 10 MJ ME/kg DM to 14% CP was sufficient for growing Boer after weaning up to the slaughtering stage. Ration with 18% CP performed better in terms of meat deposition in the carcass.