Effects of shelter and body condition on the behaviour and physiology of dairy cattle in winter

Our objective was to understand how body condition and shelter affected behavioural and physiological responses of dairy cattle during winter weather. Twenty non-lactating dairy cows were divided into two groups of 10. Within each group, five animals had a high body condition score (9 out of 10) and five had a relatively low condition score (4 out of 10). Each week, the groups were switched between an indoor and an outdoor pen for a total of six weeks. The outdoor pen was equipped with sprinklers and fans to simulate continuous winter weather. We measured time budgets (time spent lying, standing, eating) and changes in lying and standing posture in response to the indoor/outdoor treatments. In addition, we measured body temperature, skin thickness, faecal glucocorticoid metabolites, plasma cortisol, thyroxine (T4) and non-esterified fatty acid (NEFA) concentrations. When cows were kept outside, they spent less time lying down, had higher cortisol, glucocorticoid, T4 and NEFA concentrations. They were also more likely to spend time in lying and standing postures that reduced the amount of surface area exposed to rain and wind when outside compared to when they were kept inside, suggesting that shelter provides benefits for dairy cows in winter conditions. While outside, thinner cows spent less time eating, particularly when temperatures became colder, had lower minimum body temperatures, were more likely to spend time lying in postures that reduced surface area exposed to rain and wind, and had lower NEFA concentrations compared to high-conditioned cows, indicating that body condition helps insulate cows exposed to winter weather. In conclusion, both shelter and body condition mitigates the effects of winter weather on dairy cows.