G. L. D. Feijo

EFEITO DO DESMAME PRECOCE NA CARCAÇA DE NOVILHOS TERMINADOS EM PASTAGEM E ABATIDOS AOS 24 MESES

Carcass characteristics of Charolais x Nellore steers, weaned at two ages: 90 (T90) or 210 days (T210) were evaluated. Sixty-three castrated calves, finished on Avena strigosa + Lolium multiflorum + Trifolium vesiculosum pasture and slaughtered at twenty-four months of age, were used. No significant differences were observed between treatments for final weight (T90=437 kg and T210=467 kg), dressing percentage (T90=53.33% and T210=52.21%), hot carcass weight (T90=233 kg and T210=244 kg) and cold carcass weight (T90=226 kg and T210=238 kg). Carcasses of the two treatments showed similar conformation (T90=10.8 points and T210=11.0 points). Also the forequarter, side and hindquarter percentages were similar between treatments, likewise no significant differences were observed for carcass, leg and arm length, arm perimeter and cushion thickness. Subcutaneous fat thickness did not differ between the two carcass groups (T90=2.56 mm and T210=2.27 mm). Results demonstrate that early weaning at ninety days of age does not affect carcass traits of steers slaughtered at twenty-four months of age, if adequate nutrition is provided during growing and finishing periods.

Feed efficiency indexes and their relationships with carcass, non-carcass and meat quality traits in Nellore steers.

Five hundred and seventy-five Nellore steers were evaluated for residual feed intake and residual feed intake and gain and their relationships between carcass, non-carcass and meat quality traits. RFI was measured by the difference between observed and predicted dry matter intake and RIG was obtained by the sum of -1*RFI and residual gain. Efficient and inefficient animals were classified adopting ±0.5 standard deviations from RFI and RIG mean. A mixed model was used including RFI or RIG and contemporary group as fixed effects, initial age as covariate and sire and experimental period as random effects, testing the significance of the regression slope for each evaluated trait. RIG was positively related to longissimus muscle area. Efficient-RFI animals had lower liver and internal fat proportions compared to inefficient-RFI animals. Efficient-RFI and efficient-RIG animals had 11.8% and 11.2% lower extracted intramuscular fat, compared to inefficient-RFI and inefficient-RIG animals, respectively. Efficient-RFI animals had tougher meat compared to inefficient-RFI animals.