Wooden breast (WB), white striping (WS) and spaghetti meat (SM) are breast myopathies of the Pectoralis major that greatly affect meat quality in broilers. To differentiate color and texture characteristics with instrumental methods, some of them applied for the first time in this species, 300 carcasses were randomly chosen from an abattoir from five different flocks from the same farm, at a rate of 60 carcasses from each flock. Twenty-four hours after slaughter, both side breasts were dissected, and yields calculated. Color was measured on the surface of the breast with a spectrocolorimeter and reflectance values obtained. Texture was measured on raw meat with a modified compression test that hinders the fiber from expanding transversally and a texture profile analysis (TPA) and also on cooked meat with a Warner–Bratzler shear and a TPA. Color differs between severity degrees, increasing redness (from −1.77 to −1.32 in WB) and, especially, yellowness (from 5.00 to 6.73 in WS) and chroma (from 5.75 to 7.22 in SM) with the severity of the myopathy. The subtraction R630 minus R580 was found to be a useful index to differentiate breast myopathies degrees. The modified compression test can be considered an effective tool to assess the hardness of different structures in each myopathy. Texture differences in the myopathies are better assessed in raw than in cooked meat.

Eighty-four Nellore bulls (269 ± 27 kg; 13 months) were used in a completely randomized design to evaluate different supplementation strategies on the performance of growing Nellore cattle grazing Panicum maximum cv. Tanzania in the rainy season and rainy-to-dry season transition. In the rainy season, 42 animals received mineral salt (MS) ad libitum and 42 received protein supplement (PR) at 1 g kg⁻¹ body weight (BW). In the rainy-to-dry season transition, 28 animals received MS, 28 received PR at 1 g kg⁻¹ BW, and 28 received a protein-energy (PE) supplement at 3 g kg⁻¹ BW. In the rainy season, the PR supplement increased average daily gain (ADG), providing a significant increase of 17 kg in final BW. In the first period of the rainy-to-dry season transition, PE promoted better performance than MS, while PR did not differ from the two other treatments. In the second period of the rainy-to-dry season transition, PE and PR increased ADG by 41% and 31%, respectively, compared with MS. In the third period, all supplements differed from each other. Bulls fed PE had greater final BW compared with animals fed PR and MS. In conclusion, during the rainy season, PR supplementation should be provided even under good pasture conditions. Also, during the rainy-to-dry season transition, protein-energy supplementation is recommended to compensate for quantitative and qualitative deficiencies of the pasture.

The aim of this study was to evaluate the effects of castration methods (surgical or immunological – GnRH vaccine) on performance and carcass traits of beef cattle raised until slaughter on tropical pasture. On Day 0, 30 crossbred beef bulls (50% Aberdeen Angus × 50% Nellore) with a bodyweight (BW) of 233 ± 38 kg and age of 8 months were randomly divided into three groups: intact males (INT) – Control, surgically castrated (SUC; Day 1), and immunocastrated (IMC; Days 1, 84 and 237). Serum testosterone concentrations, scrotal circumference, average daily gain, and ultrasonic backfat depth were evaluated at 42-day intervals (eight evaluations). All animals were slaughtered for the evaluation of carcass traits on Day 336. The GnRH vaccine was efficient in suppressing serum testosterone concentrations (P = 0.02) and scrotal circumference (P < 0.01). No difference in performance was observed between IMC and SUC animals, in which average daily gain was reduced by 14% (P < 0.01) and final BW by 7% (P < 0.01) compared with the INT group. Regardless of the method used, castration improved carcass traits by reducing carcass drip loss during cooling (P = 0.02), by increasing hindquarter percentage (P < 0.01), and by tending to increase the proportion of noble cuts (P = 0.05) compared with the INT group. However, the surgical method was more efficient than the other treatments by increasing fat deposition in the carcass (P < 0.01). Anti-GnRH immunisation in beef cattle raised on tropical pasture can replace surgical castration, but both methods reduce performance. However, in this production system, castration could be an efficient method to add value to the carcass by increasing the hindquarter proportion and fat deposition.

Sixty 18-month-old steers (20 Nellore, 20 F1 Simmental × Nellore and 20 F1 Angus × Nellore with average body weight of 265.6±6.4 kg; 325.3±4.7 kg and 324.6±6.0 kg, respectively) were used. The effects of feeding regime and genetic group on physical carcass composition, empty body composition, composition of the gain, as well as the pattern of tissue deposition were evaluated in this trial. The interaction between genetic group and feeding regime was not significant for any variable evaluated. Animals fed at the maintenance level produced carcass with larger proportions of bones and muscle than the animals fed ad libitum and Nellore animals had larger muscle portion and smaller adipose tissue portion on the carcass than the crossbred animals. Nellore animals and those fed at maintenance had smaller amount of total fat in the carcass than the crossbred animals and those fed ad libitum, respectively. Fat was deposited more pronouncedly in the intermuscular depot, followed by the visceral depot. The rate of deposition of the carcass tissues was smaller in the Nellore animals and in the animals fed the diet with concentrate allowance equivalent to 1% body weight (except for subcutaneous fat tissue), when compared with the crossbred animals and those fed the diet with 2% BW on concentrate, respectively. The rate of fat deposition on the visceral depot was larger in the F1 Angus × Nellore animals and on those fed the 2% of BW of concentrate diet when compared with F1 Simmental × Nellore animals and those fed the diet with the lowest concentrate allowance (1% BW)