Performance and Behavioural Responses of Group Housed Dairy Calves to Two Different Weaning Methods

Simple Summary Removal of the milk feed, more commonly known as weaning, is considered as a major stressor in the early life of a calf, which, if handled improperly, can have a negative impact on both calf performance and well-being. Traditional methods of assessing the impact of weaning have involved behavioural observations and blood sampling, which can be impractical for farmers and invasive for animals involved. Recently, developments in technology have increased the availability of on-farm non-invasive devices which allow automatic and remote collection of behavioural and physiological data linked to animal health and well-being. This study aimed to use conventional measures of animal performance in combination with non-invasive monitoring technologies to examine the impact of two different weaning methods in group housed calves. Results indicated that both gradual and abrupt methods of weaning described in this study can be used without significant impact to calf live weight at 63 days of age. However, data from the monitoring technologies indicated that weaning method can have an impact on calf behaviour and use of automatic milk and concentrate feeders, providing information on overall calf well-being. The results of this study indicate how monitoring technologies can be incorporated on-farm and how the information can be used to highlight potential areas of increased calf frustration within common calf management practices. Abstract The weaning of dairy calves is a significant stressor which can impact on calf performance and welfare. However, many traditional methods of assessing the effects of stressors can be invasive and impractical for farmers. This study aimed to use a combination of non-invasive monitoring technologies alongside traditional measures of calf performance to examine the impact of two contrasting weaning methods commonly used on dairy farms in the United Kingdom. Ninety group-housed Holstein Friesian calves were allocated to one of two weaning methods: (i) gradual weaning (GW) with volume of milk replacer (MR) stepping down from 36 days of age and complete withdrawal of MR at 57 days of age and (ii) abrupt weaning (AW) with consistent daily volume of milk replacer and complete withdrawal of MR at 50 days of age. Feeding regimes were such that calves from both treatments were offered the same total amount of milk powder. Gradually weaned calves displayed increased solid feed intake at an earlier age when compared with AW calves. Feed conversion efficiency (FCE) was reduced in gradually weaned calves between days 36 and 49. However, there was no difference in live weight (LWT) or average daily gain (ADG) throughout this period. Abrupt weaning at 50 days of age resulted in decreased ADG and FCE between days 50 and 56. However, there were no treatment differences in ADG between days 57 and 62. Live weight tended to be increased by 2.2 kg in GW calves when compared with AW calves at the end of experiment on day 63. Frequency of unrewarded visits to the milk feeder throughout the pre-wean period was consistently increased in GW calves. Daily lying time was reduced in AW compared with GW calves in the days following abrupt weaning (days 50–55). However, these differences did not persist between days 57 and 62. Heart rate variability (HRV) tended to be decreased in GW compared with AW calves in the period following complete withdrawal of milk replacer. Findings from the current study suggest that calves offered the same total amount of milk powder can be weaned either gradually from 36 days of age or abruptly at 50 days of age without significant impact to live weight at 63 days of age. However, both behavioural and physiological data collected using the methods described could suggest that gradual weaning of calves from 36 days of age results in an increase in underlying frustration. This study highlights the potential of using a combination of non-invasive monitoring technologies in assessing calf response to common management practices.