Stanton PhD Thesis final_docx - Atrium - University of Guelph

calves were still allowed access to the dam but were restricted from sucking, beef calves walked
more than control animals that could still suckle their dams (Haley et al., 2005). In the second
stage of the two-staged weaning process, when all calves were removed from the dam, two-
staged weaned calves walked less than control animals. While comparison between the results of
the two-stage weaning study and the current study must be tempered by different social stressors
(isolation versus mixing stress) it does suggest a common response to a weaning and social
stress.
In contrast to the transition period, calves that had higher activity between 4 and 11 days
post-weaning gained more weight. This may further explain the results of the study of Chua et al
(2002), in which pair housed milk fed calves were more active than individually housed calves
during the 8 week study period, which included weaning. However, a positive association
between growth and activity following an initial adaptation to weaning has not been documented
prior to the current study.
A greater lying duration was positively associated with higher body weight gain during
the first week post-weaning for calves from Nursery 2 during the transition period and for all
calves during the plateau period. In previous studies, time spent standing was not different for
calves that were provided warm water post-weaning to alleviate weaning distress in comparison
with calves that were abruptly weaned despite other behavioral indicators of decreased weaning
distress (Budzynska and Weary, 2008). However, time spent resting was higher after weaning for
beef and dairy calves with the two-stage weaning (Haley et al., 2005; Haley, 2006). In addition,
the lying time of calves decreases following mixing with unfamiliar animals (Raussi et al.,
2005). This indicates that in general, calves respond to these stressors by decreasing resting time.
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