Factors intrinsic to handling and transport in pre-slaughter behavioural changes in beef cattle.

The aim of this study was to evaluate handling and transport variables as potential causes of disturbed behaviour in response to seeing a person on an overhead observation platform during pre-slaughter in batches of females and castrated males composed of pure or crossed Bos Taurus animals (Aberdeen Angus, Red Angus, Hereford and Charolais) with a maximum of 37.5% Bos indicus, and maturity at slaughter varying from zero to eight teeth, coming from pasture and confined systems. For the batches of castrated males, the independent variables included the distance covered on the trip, and the handling and facilities on the farms. For the female batches, the variables were travel time and waiting time prior to unloading. For both sexes, the presence of horns in the batches and the load density were included in the regression equations. Disturbed behaviour, the result of factors related to animal handling and transportation, is detrimental to satisfactory results in production systems. It is up to the managers in the production chain to seek alternatives in order to minimise inappropriate behaviour, which is one determinant of loss. Handling and transport are determining factors in the behaviour of beef cattle during the pre-slaughter period.

Environmental factors on the probability of pregnancy in early or conventionally weaned beef cows.

Potential variables for the reproductive success of beef cows were evaluated. Included in the model were the age of the cow at calving; the interval between the Julian calving date and the end of the breeding season; the body weight and conditions at calving, at 75 days post-partum and at the end of the breeding season; and the mean daily variation in weight between these dates. Logistic regression was used in the analysis, with the parameters evaluated using the odds ratio statistic, estimating the chance of pregnancy. The mean rate of pregnancy was 84% and 55% for early and late-weaned cows, respectively. For early weaned cows, the regression variables were the Julian calving date, age of the cow, weight gain from calving to 75 days post-partum, and from 75 days post-partum to the end of the reproductive period. For late-weaned cows, there were only two regression variables, weight at calving and weight gain from calving to the end of the reproductive period. For every year above the average age of the herd, early weaned cows have an 80.9% greater chance of pregnancy, while a reduction of one year reduces the chance of pregnancy by 44.7%. In early weaned cows, every seven days after the mean Julian calving date reduces the chances of pregnancy by 22.6%, whereas every seven days before the mean calving date increases pregnancy by 29.2%. Greater gains in cow body weight, from calving to the end of the reproductive period, determine a greater probability of pregnancy.