Effect of an innovative housing system and pen enrichment on veal calf welfare with focus on animal health and behaviour

In the Netherlands, the intensification of livestock farming and the close proximity to urban regions raise concerns regarding emissions, zoonoses, antibiotic use and animal welfare (Post et al., 2020; Smit & Heederik, 2017). The veal calf sector currently has to deal with high antibiotic usage and new regulations aimed at reducing nitrogen emissions and improving animal welfare. To future-proof the sector a new housing system has recently been developed, the Calf Clean System (CCS). In the system the calves are housed on rubber-slatted floors, under which the manure is separated with a cooled V-shaped floor into a thick and thin fraction and removed frequently by a urine gutter and a manure scrape. Additionally, the air underneath the floor is removed with a separate ventilation system providing a better indoor climate. Besides optimal housing climate, welfare-enhancing measures, such as pen enrichment, are considered essential to future-proof the veal calf sector. To investigate effects of housing systems and pen enrichment, the current PhD project will focus on the health and behaviour of veal calves during the entire rearing period. Animal health and welfare will be assessed regularly by conducting behavioural observations, clinical scores, blood sampling (as part of regular checks), saliva sampling, antibiotic usage, the consumption of roughage, water, and milk, and pathological scores after slaughter. Additionally, based on real-time sensors CO2 and NH3 air concentrations will be determined continuously and based on these concentrations, emissions can be calculated. The aim of the PhD study is to investigate the impact of different housing conditions (complete usage of CCS, partial usage of CCS and normal conventional farm conditions) and enrichments (e.g. additional brushes, ropes, or different interactive items). The final purpose of this project is to help the veal calf sector move towards a future-proof housing system in which the welfare of calves is improved.