Behaviour of foster cows and calves in dairy production

By using foster cows to raise calves in dairy production the calves are given the possibility to perform more of their natural behaviours, such as suckling, playing and having social contact. In this thesis the acceptance of calves by foster cows of different breeds and stages of lactation, the development of an attachment between foster cows and calves and the possibility to reduce stress at weaning and separation was investigated. In paper I cows of the breeds Swedish Red (SR) and Swedish Holstein (SH) from early to late lactation were tested with regard to their ability to accept four alien calves. There were no differences between the breeds or the different stages of lactation. SR cows were more social towards their calves and SR calves suckled and tried to suckle more than the SH calves. In paper II foster cows having four foster calves each were observed for 24 hours at three different occasions. All social interactions between the foster cow and individual calves, along with sucklings were recorded. In all groups the foster cows directed more social behaviour to one or two calves, and those calves were interpreted to have the closest attachment to the cow, but the identity of the preferred calves was different during the different weeks. The attachment was not correlated with either the suckling duration or the weight gain of the calves. In the third study two different ways of weaning foster cows and calves after 9 weeks of free suckling was tested. Either the calves were prevented from suckling by separating them from the cow (control), or they were prevented from suckling by a nose-flap that was fitted in the nose of the calves and kept with the cow for another two weeks after which they were separated (two-step). Both cows and calves in the two-step treatment vocalised and walked less than the cows and calves in the control treatment both when comparing time of weaning and the time of separation. The heart rate was lower in the two-step calves and they had a decrease in the level of saliva cortisol compared to the control calves. In conclusion, cows of both SR and SH breed and from early to late lactation accept being foster cows, foster cows seems to attach to one or two of her foster calves, and the two-step weaning process reduce the stress for both foster cows and calves after a long period of suckling