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Context and issues

Respiratory diseases particularly affect young cattle, with health and economic consequences. Most cases occur in the weeks following the transfer of animals from 'breeder' farmers to fattening centres. Intermediaries manage these transfers, collecting the cattle purchased from the breeders in sorting centres. They are then divided into batches of animals of similar weight and sold to the 'fattener' farmers. Two logistical factors dependent on these intermediaries have been identified as impacting on the risk of developing respiratory diseases: the total distance travelled by the animals between birth and fattening, and the number of different origins (i.e. breeders) of the animals within a batch. An increase in either of these factors has a negative impact on the health of the animals and their performance on fattening. The aim of this work was to develop algorithms that would make it possible to optimise these two factors and thus limit the risks of respiratory diseases in young cattle.

Results

Two algorithms were developed by researchers from the BIOEPAR (Animal Health) and MaIAGE (MathNum) units. They were tested on a dataset of 9701 batches of young cattle created in 13 different sorting centres by the Ter'elevage breeders' cooperative. The first algorithm assigns the animals to the sorting centres by minimising the travel distances of the animals, while respecting the respective maximum capacities of the centres. On this dataset, the algorithm reduced the total travel distances, particularly the longest ones (-18% for journeys of more than 300km on average). The second algorithm recomposes batches of young cattle to minimise their number of origins, respecting the number and breed of young cattle in the batch. An index evaluating the risks of cross-contamination according to the composition of the batches was associated with it. The optimisation resulted in a 35% decrease in the average number of origins per batch and a substantial decrease in the associated risk index.

Perspectives

The algorithms developed are publicly available to the players in the sector. Their use on other datasets than that of the Ter'elevage cooperative would make it possible to identify improvements to be made to them, as well as their possible interest as tools to help manage the constitution of batches in sorting centres. Furthermore, the pathosystem involved in respiratory diseases is complex and still poorly understood. New knowledge on this subject would make it possible to improve the proposed risk index, as well as to better evaluate its relationship with the occurrence of respiratory diseases.

Valorisation

This work is part of the PSDR 4 project Sant'Innov. In addition to the two publications and the conference proceedings below, they were also presented at a trade show (SPACE 2019) and during a training day for teachers in agricultural high schools. The two algorithms produced are publicly available on the SourceSup institutional forge.

Bibliographic references

Morel-Journel T., Vergu E., Mercier J-B., Bareille N., Ezanno P. (2021) Selecting sorting centres to avoid long distance transport of weaned beef calves. Scientific Reports 11(1), 1-10. doi:10.1038/s41598-020-79844-4

Morel-Journel T., Assié S., Vergu E., Mercier J-B., Bonnet-Beaugrand F., Ezanno P. (2021) Minimizing the number of origins in batches of weaned calves to reduce their risks of developing bovine respiratory diseases. Veterniary Research 52(1), 1-12. doi:10.1186/s13567-020-00872-z

Morel-Journel T., Herve L., Assie S., Mercier J-B, Vergu E., Ezanno P., Bareille N. (2020) Pourquoi et comment repenser les pratiques d’allotement des broutards en vue de l’engraissement ? Dans Actes des 25emes Rencontres autour des Recherches sur les Ruminants 2020. Institut de l’elevage (Idele), Ed Technipel, Paris.