The behavioural need for lying and feeding in the high yielding dairy cow

Abstract

Experiments were conducted to examine the impact of high milk yields on the behaviour and welfare of dairy cows. A preliminary study determined the social interactions existing within a group of 60 cows from which sub-samples of 20 high and 20 low yielding cows, that were not observed to interact with each other, were identified. These cows were used to examine the behavioural strategies employed by dairy cows coping with increased nutritional demands from milk production. Grazing time significantly increased with milk yield, consequently reducing lying time. A second study measured the appetite of high and low yielding cows for concentrates, using operant conditioning. The high yielding cows demonstrated no greater appetite for concentrates, but post-testing behavioural observations indicated greater appetite for forage, suggesting increased motivation to feed. Subsequent experiments investigated the behavioural effects of lying deprivation on dairy cattle welfare, further examining the feeding-lying conflict. Cows forced to stand had reduced milk yields and demonstrated behavioural signs of fatigue, frustration and stress, which were cumulative. When deprived of lying, a post-deprivation increase in this activity was achieved by reducing feeding time. When deprived of both lying and feeding, a feeding, not lying, post-deprivation increase was observed. However, lying was not reduced to extend feeding time. In conclusion, the motivation to feed was greater in high yielding dairy cows. This resulted in extended grazing and a reduced lying time. Lying can be regarded as an important and highly motivated behaviour and may compromise welfare if reduced. The legitimacy of using individual dairy cows as replicates in the statistical analysis of their behaviour was also investigated. There was no significant difference in the coefficients of variation between cows that were free to interact, and those that were not, for a range of behaviours. Therefore, those cows able to interact did not appear to influence each other's behaviour, supporting the use of individual dairy cows as replicates