Stanton PhD Thesis final_docx - Atrium - University of Guelph

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List of Figures Figure 2.1: Timeline describing trial milestones and behavioral observations, with average ages (mean ± s.d.) at observation and measurements ........................................................................... 60 Figure 2.2: Method for behavioral scoring of the calves, conducted every other week .............. 61 Figure 2.3: Proportion of calves in each lethargy response category for the active diarrhea (n = 229) and healthy controls (n = 47) ................................................................................................ 62 Figure 3.1: The average number of steps per day (mean ± standard deviation ) by weight gain category in the first week post-weaning for calves (n = 70) following weaning and relocation to a novel environment. ....................................................................................................................... 82 Figure 3.2: The total lying duration per day (hours) (mean ± standard deviation ) for calves (n = 70) following weaning and relocation to a novel environment, and total lying duration per day by weight gain category in the first week post-enrolment ................................................................. 83 Figure 3.3: The average number of lying bouts (mean ± standard deviation ) per day for calves (n = 70) following weaning and relocation to a novel environment, and number of lying bouts per day by weight gain category in the first week post-enrolment ............................................... 84 Figure 3.4: LSMEANS (±S.E.) of post-weaning weight gain for total lying duration by nursery location interaction (P = 0.01) ...................................................................................................... 85 Figure 3.5: LSMEANS (±S.E.) of post-weaning weight gain for time at the bunk (% of total observations) by nursery location interaction (P = 0.03), controlling for Day 0 weight, antibiotic treatment, and pre-weaning calf starter intake, with random effects for group nested within group size. ............................................................................................................................................... 86 Figure 4.1: Steps per day (Mean and 95% Confidence Interval ) for each of the time periods, controlling for breed and age as fixed effects, replicate as a random effect and calf nested within replicate and treatment as a repeated measure. ........................................................................... 100 Figure 4.2: LSMeans ( ± S.E.) of total daily lying time (hours), controlling for breed and age with a random effect for replicate and calf nested within replicate and treatment. .................... 101 Figure 5.1: Images taken from farm prior to the start of the trial and used as guidelines to identify ear droop. Shown: from left to right: Unilateral ear droop and ear droop with abnormal head position ............................................................................................................................... 132 Figure 6.1: Timeline of trial events ............................................................................................ 157 Figure 7.1: Timeline of trial events ............................................................................................ 193 Figure 7.2: Difference in least squares means (± SE ) of the weight (kg) of heifers with BRD60 1 relative to calves without BRD60 at 5 time points at a commercial heifer raising facility, controlling for birth weight, age at measurement and season with random effects for source farm and weekly enrolment cohort. ..................................................................................................... 194 Figure 7.3: Differences of least squares means (± SE ) of the weight (kg) of heifers with no prior history of bovine respiratory disease that received tulathromycin at study enrolment relative to heifers that received oxytetracycline at study enrolment at entry at 5 time points at a commercial heifer raising facility. The linear mixed models controlled for birth weight, age at measurement x
and season as fixed effects and for source farm and weekly enrolment cohort as random effects. ..................................................................................................................................................... 195 Figure 7.4: Time to event analysis for age at first calving stratified by BRD60 status with culled heifers censored (P = 0.02). ........................................................................................................ 196 xi
Page 1 and 2: AN EVALUATION OF THE IMPACT OF MANA
Page 3 and 4: differences in weight gain or calf
Page 5 and 6: 3.2.2 Experimental Study Design 68
Page 7 and 8: 7.4.5 Culling and mortality prior t
Page 9: Table 6.5: Reasons for death loss a
Page 13 and 14: , which requires that “all calves
Page 15 and 16: ehaviour of dams challenged with LP
Page 17 and 18: In cattle, early disease detection
Page 19 and 20: increased rest and decreased appeti
Page 21 and 22: 1.4.2 Nutritional Stressors Dairy c
Page 23 and 24: humans, the metabolic rate increase
Page 25 and 26: Without human intervention, calves
Page 27 and 28: average group size of three or four
Page 29 and 30: al., 2004). Group composition and g
Page 31 and 32: first is the addition of antibiotic
Page 33 and 34: viral diarrhea virus (BVDV) bovine
Page 35 and 36: 1.7 CONCLUSION AND THESIS OBJECTIVE
Page 37 and 38: Buhman, M. J., L. J. Perino, M. L.
Page 39 and 40: Hemsworth, P. H., G. J. Coleman, J.
Page 41 and 42: Schein, M. W. and M. H. Fohrman. 19
Page 43 and 44: Waltner-Toews, D., S. W. Martin and
Page 45 and 46: ehavioural observations ( Borderas,
Page 47 and 48: and had access to ad libitum calf s
Page 49 and 50: may indicate abdominal discomfort,
Page 51 and 52: identified in 5% (40/788) of calves
Page 53 and 54: of diarrhea in calves on this farm
Page 55 and 56: The most common response to the vig
Page 57 and 58: at any observation period. For this
Page 59 and 60: 3 was associated with lower ADG rel
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of heifers to allow them to calve a
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2.5 REFERENCES Al-Chaer, E. D. & Tr
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Panivivat, R., Kegley, E. B., Penni
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Table 2.2: List of exclusions used
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Table 2.4: The lsmeans ± S.E. of t
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Figure 2.1: Timeline describing tri
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Proportion of calves performing beh
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in a lower rate of vocalizations an
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sites. During the summer months bot
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treatment and weight gain category.
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pre-weaning calf starter intake, an
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Calves spent a total of 13 ± 6 (me
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calves were still allowed access to
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It was hypothesized that the more t
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calves to consume sufficient calf s
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Table 3.1: Descriptive list of obse
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Number of steps per day 7000 6000 5
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Number of lying bouts per day 35 30
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Weight gain (kgs) first 7 days post
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The concept of separating stressors
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were bedded with straw. While house
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4.2.5 Data Collection Calf starter
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4.3 RESULTS enrolment. On average,
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4.3 DISCUSSION There was no effect
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4.4 REFERENCES Chua, B., E. Coenen,
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Steps per day 2500 2000 1500 1000 5
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Appendix 4.1: Scoring sheet used fo
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positive for M. bovis and 4 differe
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feedlots (Van Donkersgoed, 1992). I
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protocol included the identificatio
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(cases) and two calves closest in a
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No statistical analysis was perform
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5.4.3 Growth Three calves returned
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5.4.4 Testing for Mycoplasma Of the
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may be an early sign of respiratory
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small number of unilateral ear droo
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evaluated for efficacy and carefull
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5.6 REFERENCES Biddle, M. K., L. K.
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USDA. 2007. Dairy 2007, part II: Ch
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Table 5.2: Incidence and median age
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Table 5.4: Breakdown of the number
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Figure 5. 5.1: 1: Images taken from
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6.1 ABSTRACT Bovine respiratory dis
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efore entry into the milking herd o
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with bovine viral diarrhea (BVD). O
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6.3.3 Outcome Measures All calves w
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tests, or multiple partial F-tests,
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The effect of treatment on height a
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this study involved continuing with
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is important to emphasize that the
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6.7 REFERENCES J. Carroll and N.E.
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Table 6.1: Disease variables consid
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Table 6.3: Least squares means ( ±
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Table 6.5: Reasons for death loss a
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CHAPTER 7: THE IMPACT OF BOVINE RES
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7.2 INTRODUCTION Bovine respiratory
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days following study enrolment than
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Age at First Calving Since age at f
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(Weaning, Transition, Grower 1, Gro
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The excluded source farm resulted i
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of calves with BRD60 survived to fi
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7.4.8 Milk Production First Test Da
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BRD before 6 months of age decrease
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BRD following movement to group hou
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calves with BRD60 were 1.5 (95% CI:
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7.7 REFERENCES Correa, M. T., C. R.
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Table 7.1: Calving Ease Scoring Sys
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Table 7.3: Least-square means (± S
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Table 7.5: Proportion of calves sur
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Table 7.7: Producers primary reason
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Table 7.9: Effect of BRD60 on calvi
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Table 7.11: Distribution of heifers
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Figure 7.2: Difference in least squ
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Figure 7.4: Time to event analysis
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CHAPTER 8: CONCLUSIONS AND FUTURE R
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Heifers with poor post-weaning grow
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strategic antimicrobial use was met
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Specifically, How can disease sever
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Does transportation, initial social
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