Influence of tropical, subtropical, and temperate climate conditions on seminal redox status and sperm quality parameters in breeding bulls.

This study evaluated the effect of climate change on andrological parameters of beef bulls raised under tropical, subtropical, and temperate conditions. Bull ejaculates were collected to evaluate seminal quality parameters, sperm membrane integrity, and redox status (SOD; GPx; GSH; GRx; CARB; DCF; and SOD/GPx ratio). Bulls located in the temperate region showed a higher sperm motility rate and percentage of viable sperm (P < 0.05). When evaluating regions independently, we observed a lower GPx activity from animals in the tropical region (P < 0.05). In contrast, we found that SOD and GRx activities, GSH content, and CARB oxidative levels were higher in the tropical region, while oxidation values of DCF were lower (P < 0.05). Braford bulls showed higher CARB and DCF levels (1.23 ± 0.61 nmol/mg and 1453.60 ± 828.63 nmol/mg, respectively) compared to Hereford bulls (1.00 ± 0.43 nmol/mg and 1138.70 ± 423.24 nmol/mg, respectively) in the temperate region. However, Nellore bulls showed higher DCF levels (650.50 ± 401.53 nmol/mg) than Braford bulls (409.40 ± 286.97 nmol/mg). In addition, the SOD/GPx ratio was lower in Braford (12.44 ± 7.64 U/mg) compared to Nellore bulls in tropical conditions (87.25 ± 2.83 U/mg). A positive correlation was found in temperate conditions between DCF levels, SOD, and GRx activities (0.51, 0.58; P < 0.01, respectively), as well as in subtropical conditions between DCF levels and GRx activity (0.53; P < 0.01). A negative correlation between the temperature-humidity index and CARB content was found in subtropical and tropical regions (-0.44; P < 0.01). We concluded that Braford breeds showed lower seminal motility, DCF contents and SOD/GPx ratios compared to Nellore bulls in tropical climate conditions. Finally, in temperate environmental conditions, Braford bulls also showed lower seminal motility but higher levels of CARB and DCF contents compared to Hereford bulls. Therefore, the existence of climatic differences between the temperate and tropical regions evaluated affected Braford bulls' seminal motility and seminal redox homeostasis.

Weaning at 30, 75 and 180 days: Comparison between immune responses of beef calves.

The interruption of the maternal-filial bond in young calves can alter the physiological responses due to increased stress at this moment. Therefore, we aimed to analyze the association between age at weaning and the immune responses of 64 beef calves weaned abruptly. The animals were distributed in three weaning (W) treatments: hyper-early (W30), early (W75) and conventional (W180). The treatments agree with the weaning ages used in cow-calf systems in South America. Blood samples were collected of all experimental animals on the day of weaning and days 1, 2 and 7 post-weaning day of the three treatments. Blood samples were used to analyze hematological variables, total plasma proteins (TPP), fibrinogen, serum amyloid A protein (SAA) and cortisol. The variables analyzed were influenced by the sampling day (P < 0.001) and the calf gender (P < 0.05), and an interaction between treatment x sampling day was observed. Over the study period, high serum cortisol levels were observed for W30 calves. The serum amyloid A protein was significantly influenced by sampling day. When compared to W180 calves, W30 and W75 animals showed prolonged concentrations in plasma fibrinogen. In addition, they presented neutrophilia and lymphopenia during the 180-187 days period, which resulted in a greater neutrophil:lymphocyte ratio (N:L ratio). Calf gender resulted in changes in the number of blood leukocytes (P < 0.05). This result provides an alert for weaning at an early age, indicating that different management strategies must be tested to minimize physiological instabilities in critical periods of the life of animals.

Attitudes of cattle veterinarians and animal scientists to pain and painful procedures in Brazil.

Recent studies have shown that cattle practitioners are concerned about painful conditions and procedures. An understanding of the attitudes toward pain is fundamental to encourage the use of pain relief in cattle. The goal of this study was to investigate the factors that influence Brazilian professionals toward the use of pain mitigation in cattle, primarily during castration and horn removal (e.g. dehorning, disbudding). To reach this objective, an online survey was conducted with veterinarians and animal scientists. The analysis was based on descriptive statistics, chi-squares tests, Fisher exact tests, and Mann-Whitney U tests. The final sample was composed of 147 respondents. Results of descriptive statistics showed that the use of medicine before a painful procedure (i.e., anesthetic, anti-inflammatory, or sedative-analgesic), was higher for adult cattle than for suckled and newborn calves. In newborn calves, those respondents who were more likely to use pain relief agreed with the statements that i) there is missing information about pain control during castration and ii) defensive movements shown by an animal during or after a procedure to justify pain mitigation in horn removal. The primary reasons for choosing a medicine were similar for both procedures: cost, anti-inflammatory effect, analgesic potency, duration of analgesic effect, duration of sedative effect, and route of administration. There was no difference in professional's decade of birth and pain mitigation use. These results may be useful to decide how to optimize the use of drugs by veterinary and animal science professions, and continuing education should help to increase pain mitigation usage.