Effect of different levels of energy on carcass composition and meat quality of male black goats kids

In this study thirty Black goat male kids were used in a 3 × 2 factorial arrangement to evaluate the effects of feeding diets containing low (LEL; 10.44 MJ ME/kg DM), medium (MEL; 11.60 MJ ME/kg DM) and high energy (HEL; 12.90 MJ ME/kg DM) levels and early castration (TRT) on carcass composition and meat quality. Half of these kids were castrated at 1 week of age and left to be reared with their dams until weaning at the age of 90 days prior to entering the feedlot. Average initial body weight of kids was 14.83 ± 0.5 kg. Intact and castrated kids were randomly assigned to one of three experimental diets (10 kids/treatment) containing15% CP and different levels of energy. Kids were fed individually and slaughtered at the end of the fattening period (119 days). Results showed that most of the dissected tissues in the carcass cuts were not affected (P > 0.05) by TRT or dietary energy levels. Castration treatment and increasing energy levels in the diets resulted in significantly higher total and subcutaneous fat% and intermuscular fat%, and lower total muscle%. As a result, intact and MEL kids showed higher muscle% and lower fat% with a higher ratio of muscle/fat in all carcass cuts than castrated and LEL or HEL kids. Muscle pH and temperature values of the loin area measured at 2, 5, 8, 24 h postmortem and after thawing were not affected by the different energy levels, but were lower pH and higher temperature values were recorded in castrated than intact kids. Water holding capacity, cooking loss%, shear force values and muscle color components (CIE; L⁎, a⁎ and b⁎ values) were not affected by dietary energy or TRT except that muscle of castrated kids had significantly higher L⁎, WHC and cooking loss% compared to intact kids. Meat from castrated and HEL animals had more (P < 0.05) fat and slightly higher protein but similar moisture and ash than intact and LEL or MEL animals. These results indicated that feeding different energy levels had no influence on meat quality attributes but castration improved fat deposition which increased under higher energy levels. On the other hand, muscularity was higher in intact kids in comparison to castrated kids.