Measuring the Effects of Housing Styles on Holstein-Cross Dairy Calves

40 pages. A thesis presented to the Department of Biology and the Clark Honors College of the University of Oregon in partial fulfillment of the requirements for degree of Bachelor of Science, Spring 2017The aim of this study was to investigate the effects of paired versus individual housing of approximately three-month old dairy calves on stress levels and overall calf health and performance. To do this, the study analyzed serum cortisol levels, fecal parasite loads (via a McMaster fecal egg count technique), and body condition scores for each of our two groups before and after our 35-day study. Each study group contained ten Holstein-cross dairy calves each. The individually housed group was housed in individual hutches, fed twice daily with ad libitum access to water. The pair-housed group was housed in a paired hutch setup, where two hutches and loafing areas were connected to create a larger, shared pen for two calves. Pair-housed animals had two feeder buckets and water buckets and were fed according to the same twice-daily protocol. Data collections were made on day zero when calves were randomly selected into their assigned group and again on day 35 when the study was finished. Paired t-test analyses were performed using before and after-study values for the three measurements conducted. Cortisol concentration results showed a significant increase in pair-housed calf serum cortisol concentrations before and after the study (p=0.012); individually housed calves saw no significant change in serum cortisol concentration (p=0.443). McMaster fecal egg count results were insignificant for both groups, although a general declining trend in eggs per gram of feces (ePG) was observed. Average body condition scores (BCS) for both groups were identical, minimally varying from the healthy BCS score of 3 (out of 5). The results suggest paired housing of dairy calves could cause increased stress, due presumably to social stressors, because this study found no correlation with paired-housing of dairy calves and decreased productivity or calf health. This study was the first of its kind to employ McMaster fecal egg counting techniques to quantify enteric parasite loads in calves for the purpose of evaluating calf health