Suckling of dairy calves by their dams: consequences on animal performances, behaviour and welfare

Summary

In most European dairy farms, calves are separated from their mothers immediately or within few hours after birth (Le Cozler et al., 2012). This separation of the calves from mothers allows to control calves’ colostrum and milk intake without affecting the quantity of milk produced by cows. During the first 1-2 weeks of life, calves are housed in individual pens in order to have a better supervision on milk ingestion and health control. After this time female calves, which are the future replacement heifers, are reared in multiple pens and fed with milk replacers or non-marketable milk. Subsequently they begin to receive gradually little quantities of solid food until the time of weaning. Male calves, instead, are sold during the first 14 days for fattening in specialized farm.
The early separation from calves and mothers is increasingly questioning the society about animal welfare and consequently requires farmers to be engaged with controversial issues related to animal care. In particular Ventura et al. (2013) evidenced that the early separation of calf and mother is perceived as a problem specifically by citizens who are far from livestock production. Some scientists also claimed that “we need to bring back dairy calves to their mother” (Agenäs, 2017). But the consequences of this practice have been studied mainly from the animal welfare point of view and not from the animal performances point of view (Veissier, Caré, & Pomiès, 2013). As regards the performance of cows (production, reproduction, health of the udder and milk quality) and calves (growth, health), they were studied in particular in the context of once daily milking, where significant losses in milk production are observed (D Pomiès et al., 2010).
The aim of this project was to study the impact of a suckling rearing system on milk yield, milk composition, growth of calves and the animal behaviour and welfare.
The project was carried out between February and July 2018 at INRA, UE Herbipole, in the site of Marcenat, France. The experiment involved 28 cows with their calves that were monitored for 13 weeks after calving. Parturitions took place between the end of February and the end of April. The 14 Montbéliarde (Mo) and 14 Holstein (Ho) cows involved in this experiment were selected on the basis of their lactation rank, date of calving, milk index and sex ratio of calves. Two experimental groups (group ‘Control’ and group ‘Mother’), composed of 7 Mo and 7 Ho cows each were made so that within each breed, the lactation rang, the date of calving and the milk yield (index for primiparous cows and total milk yield during the previous lactation for multiparous cows) were equivalent.
In the ‘Control’ group, the calves were separated from their mothers within the few hours after birth and were housed in individual pens, fed twice a day with milk from the tank for 7 days. Successively they were placed in a collective park for 9 weeks and fed with bulk milk (up to 10 kg/day) and concentrate (up to 2 kg/day) by an automatic feeder and quality hay fed ad libitum. Weaning was made after 10 weeks when calves’ live weight was about 100 kg. Then, calves were fed with concentrate (up to 4 kg/day) and good quality hay fed ad libitum.
In the ‘Mother’ group, the calves spent 5 days after parturition in an individual calving pen with their mother in order to allow mother-calf attachment. Cows were taken to the parlour to be milked twice daily at approximately 07:30 and 16:30. After this period, both cow and calf were moved to the collective park for 9 weeks. Cow-calf contact was allowed during the day: calves had free access to the stabling of mothers for suckling between the return of the morning milking and the departure for the evening milking. During the night they were separated from the mothers and housed in the calves’ collective park, next to the stabling of the mothers. They could see their mother, at least at the level of the separation of the 2 parks. Calves suckled the cows freely during the day and had access to concentrates and good quality hay at libitum 24h a day. Weaning was made after 10 weeks when the calves’ live weight was about 100 kg. Then the calves were fed with concentrate (up to 4 kg/day) and good quality hay ad libitum.
During the experiment, measurements and analyses concern milk production and composition, cow’s body weight (BW) and Body Condition Score (BCS), calves’ growth, individual quantity of milk and concentrates ingested by calves in the group ‘Control’, quantity of concentrate ingested by calves group ‘Mother’, health events of cows and calves and different types of behavioral observations on all the animals involved in the study.
Our results showed that from the point of view of production performances, this system has a strong impact on milk production in terms of quantity and composition. Loss of milk is substantial compared to a classic rearing system. The reduction in milk fat content and, in our case, the increase in milk protein content affects the composition and quality of the milk. On the other hand, the performances of the calves were positively affected by this practice.
From the behavioural point of view, this system has influenced the maternal behaviour of the cows in terms of preferences towards their calves and has influenced the social interactions of the calves ‘Mother’: the presence of cows stimulates the social interaction of young animals. The more critical aspect of this practice was the moment of weaning. It is important to remember that weaning is always a stressful moment for calves, even in the classic breeding system (Weary & Chua, 2000).
But in suckling rearing system, the impact on animal welfare was even strongest, and above all it involves both calves and cows. The separation of the animals caused a strong stress that lasts for a few days and affects the production of milk for the cows and the growth of the calves.
In conclusion we can say that the natural suckling system affects both the production performance and the behaviour and welfare of the animals. The presence of positive and at the same time negative aspects does not allow us to give a unidirectional opinion on the evaluation of this system, but further studies are required to evaluate this practice more completely, especially from the economic point of view.