Funder and dates: Scottish Government funding; Horizon 2020; industrial funders
Collaborators/partners: SRUC and several others including Roslin Institute, University of Edinburgh
Worldwide up to 15% of lambs born fail to survive to weaning. Most of these lambs die within a few days of birth, for a variety of reasons but particularly due to starvation and hypothermia. This occurs because ewes and lambs do not form an adequate bond, and the lamb may get lost or not get sufficient milk from its mother. Our research has focused on the behaviours that occur when the ewe gives birth, and the responses from the newborn lamb, which ensure that the attachment process between mother and young occurs properly and that the lamb is cared for by its mother. Forming a good relationship with the ewe not only provides the lamb with milk but helps the lamb keep warm, fight of possible infection and develop properly by learning the skills it will need to cope as a sheep in the flock. This is a long running area of research but our current focus is on improving the survival of larger litters of lambs, and understanding the benefits of a good maternal relationship for both mothers and offspring. We have also investigated some of these responses in other species, including cattle and horses.
Our research has shown that ewes that are highly maternal when they give birth (e.g. spend a long time licking or grooming their newborn lambs and bleat to them very often) continue to show high levels of maternal care throughout lactation until weaning, and are also very maternal when they are pregnant and give birth again. This is related to the amount of oestrogens that are in the ewes blood just before she gives birth. We have also shown that when ewes do not get sufficient food to eat in late pregnancy then they show less maternal care towards their lambs than if they are well fed. We have found that the behaviour of the lamb is just as important as the maternal care of the mother in ensuring that it survives. Lambs that stand quickly after birth and find their way to the udder to suck soon after birth are more likely to survive than lambs that are slow. Lambs that are slow to stand and suck may because they have had a long or difficult birth, because they are small or light weight, because they are born as part of a triplet or larger litter or because they are of particular breeds which are not as active at birth as others. These research findings have helped us to develop practical strategies to improve lamb survival on farm.