Decoding calf patterns : Advancing automated health monitoring with algorithmic insights

Abstract

World milk production reached 887 million tonnes in 2020 (FAO, 2022). With such high demand worldwide, dairy cows who produce the milk need to keep giving birth to renew the lactation in order to produce milk. Most female calves will be kept as heifers for the dairy industry, while the male (and some female) calves are not needed. The veal industry was therefore developed (mainly in Europe and North America) to make use of the dairy calves that are not wanted or needed for herd replacement, commonly referred to as 'surplus' calves.Although there are a number of possible routes for surplus dairy calves (Haskell, 2020;Webb et al., 2023), those calves destined for veal production are typically transported from different source dairy farms, sometimes across country borders, at the early age of around two to four weeks to a fattening veal farm (Marcato et al., 2018). At the veal farm, the calves are grouphoused, typically in small groups of five to ten, but sometimes in large groups of 40 to 70 calves, with typically 1.8 m 2 per calf, on wooden slatted floors. Veal calves are fed milk replacer in open troughs or buckets if housed in small groups, or via an automated milk feeders if house in large groups, until slaughter for the 'white' veal calves, and for eight weeks for the 'rosé' veal calves. Next to milk replacer, the calves receive solid feed, typically a mixture of concentrates and roughage (e.g. straw) until slaughter at approximately six (white) to eight (rosé) months of age (EFSA AHAW Panel, 2023). Veal calves do not typically receive enrichment, unless housed in the large groups, and do not typically have access to outdoor spaces. This production system allows veal calves to be raised efficiently, allowing each step of the chain to be considered and controlled (Renaud and Pardon, 2022), to end up with relatively high-quality meat products which fetch a high price with consumers, while using minimal resources.The Dutch veal sector is the biggest veal producer in the EU, accounting for 36% of the total production in 2020 (Berkhout et al., 2021). With around one million veal calves being kept in approximately 1,600 fattening farms 1 , the Dutch veal sector produces 1.6 to 1.7 million calves per year (Berkhout et al., 2021). These calves are transported from their source dairy farms all across Europe to the collection centres first, where they are sorted based on weight, breed, or conformation, before being sent to the fattening farms (Damiaans et al., 2019). This dairyveal chain presents potential concerns for calf welfare, including transportation of young animals, high risk of disease, and barren housing (Webb et al., 2023). One important concern for the farmers in this production system is the high morbidity (Sandelin et al., 2022) and high mortality rates (