Signs of hunger in dairy calves indicate suboptimal periods in two weaning methods : [Preprint]
In order to promote rumen development by stimulating concentrate intake, dairy calves are usually fed low amounts of milk, however this may result in prolonged hunger. Furthermore, calves are often weaned off milk without considering individual capacity to feed on solid food. We investigated the effects of two feeding regimes differing in milk allowance and in how milk was reduced on signs of hunger and concentrate intake. After birth, 17 calves were housed individually for two weeks. Then, calves were moved to a group pen and nine calves were assigned to the weaning method "individual weaning" (restricted milk amount before gradual weaning, gradual weaning off milk dependent on concentrate intake), the other eight calves to "ad libitum" (high amount of milk before gradual weaning, gradual weaning off milk on a fixed schedule). Average weaning age did not differ between treatments but varied greatly between individual calves. Before gradual weaning, individually weaned calves engaged in more unrewarded visits to the milk feeder than ad libitum calves. During gradual weaning, the number of unrewarded visits of individually weaned calves decreased, while it increased in ad libitum calves. During unrewarded visits, the number of contacts with the teat increased during gradual weaning in both weaning treatments. Whereas the increase was only marginal in individually weaned calves, it was considerable in ad libitum calves. Concentrate consumption increased in both groups from before to during gradual weaning. However, both before and during gradual weaning, individually weaned calves consumed a higher proportion of their daily concentrate allowance. On average, individually weaned calves consumed less milk and more concentrate over the course of the weaning process. The findings regarding unrewarded visits to the feeder, however, indicate that calves in both treatments showed signs of prolonged hunger before and/or during gradual weaning and stress the importance of further improving weaning treatments.