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Context and issues

A new method of rearing dairy calves with nurse cows is developing in France and could be a solution to the societal demand for more natural rearing methods that respect animal welfare. This practice consists of adopting 2 to 3 calves from a nurse cow that the farmer does not wish to keep in the dairy herd. The little information available seems to indicate a beneficial effect for the calf with better growth and a lower incidence of diarrhoea. Cryptosporidium is the main pathogen responsible for neonatal diarrhoea in calves and its epidemiology is highly dependent on the calf's management and environment. Thus, the objective of our study was to describe precisely the behaviour of calves reared under milk during the neonatal period and then to evaluate the infection by Cryptosporidium and its impact on diarrhoea.

Results

The study was carried out on 20 organic dairy farms in western France on over 600 calves. The calves were fed in three successive phases: a phase with the mother of 4.5 days on average, an optional artificial milk-feeding phase (half of the calves) and finally a phase of adoption by a nurse cow at an average age of 8 days. The artificial milk-feeding phase, carried out with milk from the farm in individual or collective huts, is practised mainly to synchronise adoptions or for the sale of calves. The study showed an overall lower level of cryptosporidia infection and incidence of diarrhoea than in the conventional system. However, the level of infection in calves was higher for births in a building or at the end of the season, during artificial feeding and during contact with another excretory calf. These initial results, which need to be confirmed on a larger scale, would seem to indicate that the feeding of calves is accompanied by a lower circulation of cryptosporidia and therefore a lower risk of neonatal diarrhoea linked to this agent.

Perspectives

Neonatal diarrhoea is one of the most important health constraints in calves. The identification of certain risk factors for cryptosporidiosis, such as artificial feeding or contamination of buildings, is a potential element of control for farmers involved in rearing suckled calves.

Valorisation

This study was carried out within the framework of the European project GrazyDaisy (Core Organic cofund, ERA-NET) by involving the network of farmers involved in the management of fed calves in the various stages of the project and the presentation of results. Numerous oral or written communications have been made at trade fairs (SPACE), conferences (GTV) or technical or professional journals (NEVA, Chamber of Agriculture). Popularisation videos are also being edited.

Bibliographic reference

Constancis, C., Ravinet, N., Bernard, M., Lehebel, A., Brisseau, N., Chartier, C., 2021. Rearing system with nurse cows and risk factors for Cryptosporidium infection in organic dairy calves. Prev. Vet. Med. 190 (2021) 105321.