Stanton PhD Thesis final_docx - Atrium - University of Guelph

pre-weaning calf starter intake, and ambient temperature with a random effect of group nested
within group size. Interactions between nursery location and behavioral measures were tested for
all behavior models.
For all models statistical significance was defined as a P-value ≤ 0.05. The co-efficients
for each variable in the models and their associated p-values were monitored for confounding.
Normality of residuals was assessed using boxplots and normal probability plots. No
transformations were required. All graphs that presented results of models that included
continuous variables were restricted to the interquartile range of the continuous variable.
3.3 RESULTS
The average calf starter intake prior to weaning was 1.21 ± 0.62 (mean ± standard
deviation) kg, 1.33 ± 0.79 and 0.92 ± 0.74kg for the High, Average and Low weight gain groups,
respectively. Calves from Nursery 1 consumed 0.48 ± 0.1 kg more calf starter than calves from
Nursery 2 (P < 0.01). Consumption of more than 0.91 kg of calf starter in the pre-wean period
was associated with a 1.7 ± 0.7 kg increase in Day 7 body weight, controlling for Day 0 weight
as a fixed effect and group nested within group size as a random effect (P=0.03). Calves that
received antibiotic treatment weighed 1.1 ± 0.6 kg more than calves that did not receive
antibiotic treatment (P=0.06).
A total of 23 (31%) calves were treated for clinical disease in the 7 to 30 days following
weaning. Of those treated, 91% (21/23) were treated for coccidiosis, and 9% (2/74) were treated
for BRD. Day 7 weight was not associated with the probability of being treated in the 30 days
following weaning, (P=0.90).
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