Levels of energy supplementation for heifers in Tifton 85 pasture on carcass characteristics, internal organs and meat quality.

The objective of this study was to evaluate the effect of different levels of concentrate supplementation on carcass characteristics of heifers finished on Tifton 85 pasture. Thirty-two cross-breed heifers (Charolais and Nellore) on average aged 25.51 months and weighing 298 kg were used in a completely randomized experiment. The animals were distributed uniformly to receive four different levels of concentrates based on the body weight: 0.0; 0.4; 0.8 and 1.2%. Animals were slaughtered at 29 months of age. There was increasing linear effect of levels energy supplementation on: slaughter weight, hot and cold carcass weights,hot and cold dressing percentage, thigh thickness, carcass compactness, and L* and b* color values. It was observed quadratic effect of levels of energy supplementation on the percentage of fat in the carcass. Different levels of energy supplementation did not modify the accumulation of vital organs and visceral fat or the sensory attributes of the meat. Higher levels of energy supplementation promote increases in carcass traits of heifers when finished on Tifton 85 pasture.

Main altered characteristics in the meat of young cattle of different sexual conditions supplemented in tropical pasture.

The aim was to identify the predominant variables in the differentiation of meat quality of cattle submitted to surgical castration, immunocastration, or non-castration and finished in a tropical pasture. Thirty-nine crossbred cattle were used and distributed in three treatments: i) surgical castration; ii) immunocastration; and iii) non-castration, with an initial mean age of 14.06±0.72 months and a mean weight of 284.10±31.40 kg. We used the principal component analysis to differentiate the qualitative meat characteristics between the treatments. Based on that analysis, we found that the first three principal components explained 71.44% of the total variation in the meat quality data, which ensures that the variation found is associated with the effect of the treatments. The characteristics correlated with the first three principal components and responsible for the discrimination between sexual conditions were subcutaneous fat thickness, instrumental meat color, cooking loss and shear force. These characteristics were similar among castrated animals, regardless of the methods. Therefore, immunological castration preserves the attributes of the meat and prevents possible damage to the physical and mental integrity of the animals. Finally, principal component analysis is an important methodology in the objective investigation of beef meat attributes.

Partum and postpartum characteristics on the postpartum rebreeding in beef cattle.

The objective was to evaluate the influence of calving and postpartum characteristics, measured in different genetic predominance, on the postpartum rebreeding. Were evaluated 437 partum from cows that received feeding management consisting of a forage base of the native field and the mating season consisted of 90 days. The measurements were used from the data base (age of cow, genetic predominance, body weight, body condition score and date of calving) of the cows in the partum and postpartum period. The variables were submitted to analysis of multiple variances, multiple regression, correlation and cluster. Already the groups formed by cluster analysis were submitted to analysis of variance and F test and the means, compared by Student's t-test, α=0.05 probability. The increase in the mean at 0.14 points in the body condition score at calving and the occurrence of calving 9 days earlier at the calving season gives the Charolais genetically predominant cows repeat calves. The Nellore genetic predominance when they calved with similar body condition score (2.32 points) and showed a negative body weight gain at weaning (-3.0 kg and -2.1 kg) showed different behaviors, where they did not repeat the offspring, when they calved and weaned with smaller body weight.

Qualitative characteristics of meat from cull cows of different genotypes and age class slaughter under different finishing systems: a meta-analytic approach.

The aim of this study was to evaluate, by meta-analysis, the quality of the meat of the cows according to genotype, termination system and age class slaughter. During an online research were identified 15 articles with information related to meat quality of slaughtered cows. The data were grouped according of the genotype of cows being: zebu or continental defined, crossed zebu x british or zebu x continental; according to termination system: feedlot or grassland; according to age of slaughter, where: up to 4 years old (young), 4-8 years old (adult) or more than 8 years old (old). The meat of the continental crossbred cows was softer than the other genotypes, both panel of evaluators and by Shear. The meat of cows finished in feedlot showed higher marbling degree in relation to meat of females finished on grassland. The reduction of the slaughter age of cows improved the meat color. The cow's genotype affects the organoleptic aspects of meat while the finished system and slaughter age affects the sensory aspects of meat.