Stanton PhD Thesis final_docx - Atrium - University of Guelph

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ased on the unique identification number assigned to each calf on arrival, determined by their order of arrival at the farm. All TUL calves were injected with 2.0 mL of tulathromycin (Draxxin, Pfizer Animal Health Group) by subcutaneous injection on the day of movement to group housing. Draxxin is a semi-synthetic macrolide antibiotic, containing 100 mg of tulathromycin per milliliter. All TET calves received 5.0 mL of oxytetracycline (Biomycin 200, Boehringer Ingelheim, St. Joseph, MO) intramuscularly on the day of movement to group housing. Biomycin 200 is a tetracycline antibiotic containing 200 mg of oxytetracycline per milliliter. The standard dose for TUL was determined based on the weight of the upper quartile of calves (78 kg) at enrollment. The dose of TET was part of the established weaning management protocol on the farm and was two-thirds of a full label dose. During the study, no antibiotics were administered in the feed or water. The 2 trial treatments were very different in appearance and volume used; therefore, the farm staff members responsible for administration of treatment at the time of enrollment were not blinded to treatment assignment. However, the decision as to which drug to administer was predetermined. As such, randomization to treatment group was not influenced by preconceived bias of the farm staff. Outcomes, such as detection of BRD and follow-up weight measurements, were assessed by a different set of staff members than those administering the treatment at enrollment, who were blind to treatment group allocation. The distribution of calves in the TET and TUL groups within a pen of 10 calves in the weaning barn was random, based upon the order in which calves were processed. Pens were open-sided. Thus, nose-to-nose and oral contact was possible between pens. 139
6.3.3 Outcome Measures All calves were monitored daily in the nursery, weaning, and transition barns by trained barn staff for the occurrence of disease, using consistent case definitions. All disease events and treatments were recorded in the farm management database (DairyComp 305, Valley Agricultural Software Inc., Tulare, CA). The farm staff recorded fever and respiratory disease as 2 separate events. Fever was defined as an animal that was dull, off-feed, listless, with a rectal temperature > 39.5°C and normal respiratory rate with no nasal discharge; respiratory disease was defined as the animal being dull, listless, with elevated respiratory rate, nasal discharge, or both. However, for the purpose of this trial, we combined these 2 diseases into one category called BRD. This approach was based on the likelihood that these 2 events are the same disease at different stages or represent animals with a slightly different clinical presentation of the same underlying condition. All calves in individual housing were treated for disease in accordance with the previously established treatment protocols of the farm. Calves were not eligible for BRD treatment for 5 d after the experimental treatment. Group-housed animals identified with BRD were treated with ceftiofur crystalline suspension (Excede Sterile Suspension, Pfizer Animal Health Group) administered at the base of the ear, according to label instructions. All calves were weighed upon arrival at the farm, upon enrollment in the study (approximately 8 wk of age), and at 6 wk after enrollment. Height at the withers (to the nearest inch) was measured at the same times as weight. Farm staff performed a gross necropsy for those calves with signs of BRD that died during the first 6 wk post-enrollment. To complete this gross postmortem examination, specific digital images of the heart, lung, intestines, and trachea were taken. These images, along with a 140
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AN EVALUATION OF THE IMPACT OF MANA
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differences in weight gain or calf
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3.2.2 Experimental Study Design 68
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7.4.5 Culling and mortality prior t
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Table 6.5: Reasons for death loss a
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and season as fixed effects and for
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, which requires that “all calves
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ehaviour of dams challenged with LP
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In cattle, early disease detection
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increased rest and decreased appeti
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1.4.2 Nutritional Stressors Dairy c
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humans, the metabolic rate increase
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Without human intervention, calves
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average group size of three or four
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al., 2004). Group composition and g
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first is the addition of antibiotic
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viral diarrhea virus (BVDV) bovine
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1.7 CONCLUSION AND THESIS OBJECTIVE
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Buhman, M. J., L. J. Perino, M. L.
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Hemsworth, P. H., G. J. Coleman, J.
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Schein, M. W. and M. H. Fohrman. 19
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Waltner-Toews, D., S. W. Martin and
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ehavioural observations ( Borderas,
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and had access to ad libitum calf s
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may indicate abdominal discomfort,
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identified in 5% (40/788) of calves
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of diarrhea in calves on this farm
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The most common response to the vig
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at any observation period. For this
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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
Page 99 and 100: The concept of separating stressors
Page 101 and 102: were bedded with straw. While house
Page 103 and 104: 4.2.5 Data Collection Calf starter
Page 105 and 106: 4.3 RESULTS enrolment. On average,
Page 107 and 108: 4.3 DISCUSSION There was no effect
Page 109 and 110: 4.4 REFERENCES Chua, B., E. Coenen,
Page 111 and 112: Steps per day 2500 2000 1500 1000 5
Page 113 and 114: Appendix 4.1: Scoring sheet used fo
Page 115 and 116: positive for M. bovis and 4 differe
Page 117 and 118: feedlots (Van Donkersgoed, 1992). I
Page 119 and 120: protocol included the identificatio
Page 121 and 122: (cases) and two calves closest in a
Page 123 and 124: No statistical analysis was perform
Page 125 and 126: 5.4.3 Growth Three calves returned
Page 127 and 128: 5.4.4 Testing for Mycoplasma Of the
Page 129 and 130: may be an early sign of respiratory
Page 131 and 132: small number of unilateral ear droo
Page 133 and 134: evaluated for efficacy and carefull
Page 135 and 136: 5.6 REFERENCES Biddle, M. K., L. K.
Page 137 and 138: USDA. 2007. Dairy 2007, part II: Ch
Page 139 and 140: Table 5.2: Incidence and median age
Page 141 and 142: Table 5.4: Breakdown of the number
Page 143 and 144: Figure 5. 5.1: 1: Images taken from
Page 145 and 146: 6.1 ABSTRACT Bovine respiratory dis
Page 147 and 148: efore entry into the milking herd o
Page 149: with bovine viral diarrhea (BVD). O
Page 153 and 154: tests, or multiple partial F-tests,
Page 155 and 156: The effect of treatment on height a
Page 157 and 158: this study involved continuing with
Page 159 and 160: is important to emphasize that the
Page 161 and 162: 6.7 REFERENCES J. Carroll and N.E.
Page 163 and 164: Table 6.1: Disease variables consid
Page 165 and 166: Table 6.3: Least squares means ( ±
Page 167 and 168: Table 6.5: Reasons for death loss a
Page 169 and 170: CHAPTER 7: THE IMPACT OF BOVINE RES
Page 171 and 172: 7.2 INTRODUCTION Bovine respiratory
Page 173 and 174: days following study enrolment than
Page 175 and 176: Age at First Calving Since age at f
Page 177 and 178: (Weaning, Transition, Grower 1, Gro
Page 179 and 180: The excluded source farm resulted i
Page 181 and 182: of calves with BRD60 survived to fi
Page 183 and 184: 7.4.8 Milk Production First Test Da
Page 185 and 186: BRD before 6 months of age decrease
Page 187 and 188: BRD following movement to group hou
Page 189 and 190: calves with BRD60 were 1.5 (95% CI:
Page 191 and 192: 7.7 REFERENCES Correa, M. T., C. R.
Page 193 and 194: Table 7.1: Calving Ease Scoring Sys
Page 195 and 196: Table 7.3: Least-square means (± S
Page 197 and 198: Table 7.5: Proportion of calves sur
Page 199 and 200: 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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