Resumo
Bos taurus indicus temperament is variable and affects beef tenderization. Our objective was to investigate temperament and performance of noncastrated Nellore and identify groups based on Longissimus lumborum (LL) pH decline as well as beef characteristics produced by those groups. We investigated 94 animals with a subset of carcasses (n = 24) selected based on LL pH at 24 h postmortem (pm) to represent two groups: resistant to pH decline (> 5.8 called pHRes; n = 10) and normal (< 5.7 called pHNor; n = 14). Steaks were fabricated from the LL muscle and randomly assigned to aging (2, 7, 14, and 21 days). Sarcomere length, cooking loss, myofibrillar fragmentation index (MFI), and WarnerBratzler shear force (WBSF) were determined. Data on temperament were investigated in a multivariate approach, while beef data were compared between groups using the analysis of variance. Rectal temperature at the beginning of the finishing phase and total weight gain were greater and related to animals in the pHRes group (p < 0.01 and p = 0.03, respectively). Temperature and pH decline curves, sarcomere length, and cooking loss revealed that pHRes produced beef with lower quality compared to the pHNor group. Results for MFI and WBSF did not show differences between groups within each time pm; however, overall steaks from pHRes were tougher (p = 0.06). Incidence of LL pH between 5.8 and 5.9 at 24 h pm did not compromise the tenderization rate or extension; however, it affected the water holding capacity in this population of Nellore cattle.(AU)
Assuntos
Temperamento/fisiologia , Bem-Estar do Animal , Carne Vermelha/análise , Análise Multivariada , Análise de Variância , Concentração de Íons de HidrogênioResumo
To determine a possible relationship between protective maternal behavior and some reproductive variables in zebu cows, 30 cow-calf pairs were estrus synchronized at 25 days post-partum. No differences were observed in the number of cows displaying estrus or ovulating between those cows reacting to more calves with higher intensity, and the rest of the herd (P > 0.05). However, significant negative correlations were found between cows reacting to more calves and the presence of follicles (-0.39; P = 0.03), and cows displaying a more intense reaction toward their calf and estrous display (-0.46; P = 0.01). Current results suggest that protective maternal components might affect some reproductive variables.
Assuntos
Feminino , Animais , Bovinos , Bovinos/psicologia , Estro/metabolismo , Reprodução , Temperamento/fisiologiaResumo
We investigated whether a panel of molecular markers previously associated with temperament has an effect on live growth traits. Phenotypic data from 412 Charolais cows categorized according to their age in adult and young cows were used to determine Pearson's correlations between birth (BW), weaning (WW), and yearling live (YW) weight and temperament traits (measured as exit velocity [EV] and temperament score [TS]). For association analysis, selective genotyping of a group of 80 cows identified as the most docile and temperamental were genotyped with a 151-SNP (single-nucleotide polymorphisms) panel of molecular markers previously associated with temperament. Significant Pearson's correlations between birth weight and weaning weight and the two temperament measurements (EV and TS) were observed only in the young cow group. Significant effects of ten SNP on BW and WW were observed. Four markers located on candidate genes for temperament traits also had an effect on birth weight and weaning weight in Charolais cows, which indicates that both traits could be influenced by the same genes.(AU)