Effect of late pregnancy management on behaviour, welfare and calf health in dairy cattle

Abstract

Studies in various animal species have demonstrated that stress during pregnancy can have a detrimental effect on progeny health and development throughout its postnatal life. If this were to apply to dairy cows, minimising stress in pregnant cows could be of critical importance in ensuring offspring health and welfare. However, relationships between maternal health and welfare and offspring performance have not been well investigated in dairy cattle. Traditionally management strategies for cows in late pregnancy (i.e. in the dry period) have focused on maximising milk production whilst minimising impacts on postpartum health. This may include management practices that can have a negative impact on the health and welfare of cows in the dry period itself. This project aimed to identify potential sources of stress associated with management practices in late pregnant cows, and to investigate its effects on offspring health, behaviour and welfare. A survey was conducted to investigate typical dry cow and pre-weaned calf management practices on dairy farms in the United Kingdom (UK). Data from 148 commercial UK dairy farms provided valuable information on dry cow and pre-weaning calf management. Procedures that were commonly practised but potentially stressful for dry cows included the abrupt cessation of milking and frequent changes in diet and social environment. Two experimental studies were conducted to investigate the impact of alternative management practices in late pregnancy on progeny welfare. The first experiment investigated the behavioural, physiological and metabolic responses of dry cows to industry minimum standards (H: high stocking group) compared to a more extensive space allowance (L: low stocking density). The offspring of these cows were monitored until weaning to assess their responses to typical dairy farm procedures. The second experiment was conducted on calves born to heifers from an out-wintering project. Pregnant heifers were kept either indoor or outdoor grazing (on deferred grass or kale) throughout the winter period. The health, growth and behaviour of offspring were monitored for the first 14 days of life. Limited feed-face space resulted in altered feeding patterns and increased competition at the feed-face. There was no association between dry period stocking density and the physiology and metabolism of dry cows. Maternal treatment had no impact on pre-weaned calf birth weight, health, growth, passive immunity, neonatal vigour and the majority of behavioural outcomes. However, H calves made more frequent social contact with companions compared to L calves and showed higher behavioural reactivity to weaning. Maternal high stocking density treatment and previous disease incidence in calves reduced the behavioural reactions to disbudding and the expression of pain-related behaviours. Out-wintering of pregnant heifers on kale showed no negative impact on growth compared to the indoor group, whilst out-wintering on deferred grass resulted in the lowest growth rate. However, out-wintering on deferred grass may have enhanced offspring social motivation and learning ability. This study has demonstrated potential associations between maternal experience during pregnancy, and offspring growth and behaviour. The effect of maternal treatment on offspring behaviour may be more likely to emerge in challenging situations. Further research will be needed to understand the underlying mechanisms and to reach definite conclusions, which would have implications for improving the welfare of late pregnant cows and their offspring.