Impact of short feed restriction to compensatory growth on the performance, body measurements, and carcass and non-carcass traits of Bunaji and Sokoto Gudali Nigerian bulls
摘要
This study investigated compensatory growth (CG) responses in Sokoto Gudali (SG) and Bunaji (BN) bulls. Forty animals (20 SG and 20 BN) were randomly assigned to two feeding levels (high-energy vs. restricted) in a 2 × 2 factorial design, with initial mean weights of 255 ± 30.0 kg (SG) and 249 ± 48.6 kg (BN). During a 30-day feed restriction phase, one group (10 SG and 10 BN) received a high-energy diet with concentrate at 2% of body weight (BW), while the second group (10 SG and 10 BN) received 1% BW. All bulls were subsequently refed a high-energy diet (2% BW) for 120 days. During restriction, bulls fed 1% BW showed reduced dry matter intake (DMI), poorer feed conversion, and decreased muscle and fat depth in the longissimus thoracis compared with those fed 2% BW (P < 0.05). During refeeding, DMI did not differ between treatments (P > 0.05). However, previously restricted bulls exhibited a higher average daily gain (ADG; P < 0.05), indicating compensatory growth. Across the entire period, bulls fed 2% BW had higher DMI but better total FCR. At the end of the refeeding period, no differences (P > 0.05) between supplementation level groups (1 and 2% BW) were observed for linear body measurements, carcass conformation, and fat classification. Sokoto Gudali cattle had greater subcutaneous fat, rib fat, hide weight, and larger linear carcass dimensions but lower dressing percentage and carcass conformation scores compared to BN cattle (P < 0.05). Bulls on the 1% BW diet achieved a mean CG index of 0.45, with no difference between breeds. Significantly, the longissimus thoracis et lumborum muscle fully recovered following refeeding. Both Bunaji and Sokoto Gudali bulls displayed clear compensatory growth after moderate nutritional restriction.