Robustness in dairy cows: experimental studies of reproduction, fertility, behaviour and welfare

A multi-sponsor project was undertaken to investigate robustness in dairy cows. The project involved both experimental approaches and those involving the analysis of national breeding data. Two of the experimental approaches used are described in this paper. Detailed recording of a 200-cow experimental dairy herd was undertaken to investigate the link between energy balance and fertility. This was facilitated by having two genetic lines and two production systems represented on the same farm. Energy balance was estimated from daily liveweight and weekly condition score data, whilst fertility was monitored using thrice-weekly progesterone assays from milk samples. Both production system and genetic lines were shown to affect several aspects of fertility. The production system effects were shown to be due to differences in energy balance whilst the genetic lines effects on fertility could not be accounted for by energy balance, implying that cows selected for high milk production probably had genes with a negative effect on fertility. The national UK breeding database was used to identify high and low ‘robustness’ animals. Farms with a reasonable sample of high and low ‘robust’ heifers were visited and heifers sampled using validated and practical tests for behavioural traits. Significant effects of robustness were found on both aggressive and non-aggressive social behaviour. No effect of robustness was found in both fear behaviour and response to human interaction. The results of these experimental studies, carried out as part of the Robust Cow project, have illustrated that by using more detailed measurements than were commonly available on commercial farms, a greater insight could be made into how energy balance and genetics affected fertility; a key relationship influencing robustness in dairy cows. The second experiment illustrated the potential of applying practical measures to score a wide range of temperament traits on farms.
The data could be used to monitor the effects of current breeding on temperament; it could also be used to look at interactions with traits and explore the longer-term possibilities of improving welfare and production on farm through selection on behavioural traits.