Housing and nutritional management to optimise dairy calf health and performance

Abstract

The success of the dairy calf rearing is largely determined by nutritional and housing management, yet both are relatively unstudied in the context of Northern Ireland (NI) dairy production systems. The aim of this thesis was to investigate management practice and housing design of dairy calf rearing systems in NI, the resultant impact on calf performance and hygiene levels in calf environments, and how elevated nutritional intake interacts with the rearing environment to impact calf energy utilisation, feed efficiency and behaviour.

A survey of 66 dairy farms highlighted that there is large variation among systems. Key issues that were observed were inadequate natural ventilation design in over 50 % of calf house and lack of measurement of key nutritional parameters (e.g., 78.8 % did not measure calf starter intake prior to weaning). Hygiene of milk feeding equipment varied and was impacted by frequency and quality of routine cleaning. Faecal contamination of calf drinking water was substantial in most farms, with Escherichia coli detected in 89.8 % of samples. 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.

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.

Date of Award	Dec 2023
Original language	English
Awarding Institution	Queen's University Belfast
Sponsors	Department of Agriculture, Environment and Rural Affairs & AgriSearch - NI Agricultural Research & Development Council
Supervisor	Niamh O'Connell (Supervisor) & Gareth Arnott (Supervisor)