Differences in lying positions, postures and angles between familiar and unfamiliar cows and in different types of weather in a pasture-based dairy herd in Uruguay.

Abstract

Lying is one the most important behaviours of the dairy cow and, therefore, an essential element in cow welfare. Lying behaviour can be affected by various factors, including social structures in the herd, housing system and weather. Cows are gregarious animals, live in groups with complex relationships and with familiar and unfamiliar cows. Lying areas in housing systems influence the way cows can perform their lying behaviour. When outside, cows tend to lie less and in different postures in bad weather. The aim of the present study was to determine if there is a difference in lying behaviour between familiar or unfamiliar cows which lie in pairs together on pasture. Lying position, posture and angle, and the type of weather have been recorded and analysed. This study was conducted in a pasture-based dairy herd of 180 cows in Uruguay. The study was divided into two phases. In phase 1, all cows that were lying together in pairs were recorded. In phase 2, all pairs of cows lying together were recorded and in addition their lying position, posture and angle were recorded. Also the type of weather was recorded. For analysis, all the pairs of cows from phase 2 were then divided into two groups. The pairs of cows which had been lying in a pair together in phase 1 as well, and therefore had shown preferential lying together at least twice, were seen as familiar cows and therefore labelled as the ‘’match’’ group. The pairs of cows which had not been lying together in a pair in phase 1, were seen as unfamiliar cows and, therefore, labelled in the ‘’no match’’ group in phase 2. There were no significant differences in lying position, posture and angle between familiar (match) and unfamiliar (no match) cows. Cows were lying in position head - back 62,7% and 61,7%, in posture head up - head up 82,7% and 84,9% and in an angle between 136° and 180° in 40,0 and 43,4% in the match and no match group respectively. No significant differences were found in lying behaviour and type of weather (lying time was not recorded). An association between lying position and angle, and an association between posture and angle was found in all the observed pairs of cows, the ‘’no match’’ group and the ‘’match’’ group. Cows were lying in position head-back and an angle between 136° and 180°, and in posture head up-head up and an angle between 136° and 180° degrees, significantly more than in other combinations of lying positions, postures and angles. Although no differences in lying behaviour between familiar and unfamiliar cows was found, these data show a discrepancy between the lying behaviour of dairy cows on pasture and the observed lying behaviour in different housing systems. The ability to show natural lying behaviour may improve dairy cow welfare and, therefore, the results of this study could be used in future design of new housing systems.