Housing and nutritional management to optimise dairy calf health and performance

Contamination in milk/milk replacer and concentrate were comparatively lower. Reduced stocking density (>2 m2/calf) was associated with lower contamination in calf pen bedding. Environmental factors such as exposure to temperatures below thermoneutral zone, elevated airspeeds (>0.4 m/s) and damp bedding tended to reduce calf growth performance.

When compared to growth potential from available diets, sub-optimal growth was associated with factors such as elevated airspeeds and larger number (>30) of animals within single housing. The range in nutritional planes of liquid diets offered to calves on farms was large, with peak allowances ranging from 4 to 8 litres per day. In a controlled experiment, elevated liquid feed planes (1200 g/day) were compared with typical NI dairy farm 14 diets (600 g/day) in the context of observed and optimal temperature (8 ℃ and 18 ℃, respectively).

This resulted in increased daily heat production, skin temperature and retained energy. In turn, these benefited calf growth performance, feed efficiency and behaviour, highlighting that elevated milk feeding rates have a positive role to play in calf rearing systems in NI.<br><br>This thesis emphasizes that sub-optimal environmental and nutritional management of calves in NI has a negative impact on growth performance and that there is scope to enhance housing design and dietary intake to improve this.

Data generated throughout these studies has allowed identification of factors affecting the ability of calves to achieve expected performance meaning that improved guidance can be given in relation to optimising the calf rearing environment to improve health, welfare and performance.