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Bovine respiratory disease in beef calves that have been recently weaned and received at a stocker cattle operation or feedlot facility is an important concern for the US beef cattle industry; BRD causes 70% of beef cattle morbidity and 50% of

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in Journal of the American Veterinary Medical Association

Abstract

Objective

To quantify haptoglobin response to respiratory tract disease in feedlot cattle, and to investigate its ability to predict disease outcome and response to antibiotic treatment.

Design

Randomized clinical trial.

Animals

60 feedlot calves with clinical respiratory tract disease.

Procedure

Calves were randomly assigned to receive a standard antibiotic treatment regimen (TRT), or to observation pens without antibiotic treatment. Serum haptoglobin concentration was measured at initial and final examinations. Calves were examined for presence of gross pulmonary lesions at slaughter.

Results

Mean ± SD serum haptoglobin concentration at initial examination was 67 ± 108 mg/dl, with range of 0 to 508 mg/dl. Haptoglobin concentration at initial examination was similar for the TRT group and the group that did not receive antibiotic treatment, but at final examination, TRT-group calves had lower (P < 0.01) mean values. Calves receiving antibiotic treatment had haptoglobin concentration at or near zero at final examination. Calves not receiving antibiotic treatment had only slightly lower mean haptoglobin concentration at final examination, compared with initial examination. Within treatment groups, haptoglobin concentration was similar for cases with different outcomes. Calves with gross pulmonary lesions a: slaughter had numerically higher, although statistically similar, haptoglobin concentrations at initial examination, compared with calves without lesions.

Conclusions

Feedlot cattle with clinical respiratory tract disease have a large and variable haptoglobin response. Antibiotic treatment resulted in lower serum haptoglobin values, although low values were not required for full clinical recovery.

Clinical Relevance

Serum haptoglobin concentration may be an indicator of response to antibiotic therapy, although it appears to be unrelated to case severity or need for treatment. (Am J Vet Res 1996; 57:646–649)

Free access
in American Journal of Veterinary Research

assigned pens. Processing consisted of recording BW of each calf; vaccination against bovine herpesvirus-1, BVDV (types 1 and 2), bovine parainfluenza-3, bovine respiratory syncytial virus, h and clostridial pathogens i ; and deworming with moxidectin. j

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in American Journal of Veterinary Research

Bovine respiratory syncytial virus is a single-stranded negative-sense RNA virus in the family Paramyxoviridae . In young calves, BRSV infection causes moderate to severe disease characterized by bronchitis, bronchiolitis, and interstitial

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in American Journal of Veterinary Research

Bovine respiratory disease represents substantial financial and animal health challenges for cattle producers. 1 It is a multifactorial disease complex caused by multiple viral and bacterial pathogens as well as environmental factors such as

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in American Journal of Veterinary Research

Although BRD has been extensively studied for many years, it remains the most costly disease of the beef cattle industry, 1 and knowledge gaps regarding its epidemiology still exist. Bovine respiratory disease has a complex causal web with

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in American Journal of Veterinary Research

Bovine respiratory disease is the most common health problem in feedlot cattle in North America. 1,2 The economic impact of BRD on the US beef industry has been reported to exceed $4 billion annually, which includes the costs for treatment

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in American Journal of Veterinary Research

Unprotected calves are highly susceptible to viral and bacterial infections associated with the bovine respiratory disease complex, 1 resulting in severe disease and economic loss. The primary viruses involved are members of the families

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in Journal of the American Veterinary Medical Association

Summary

To assess the effects on heart and lung function, a tiletamine-zolazepam (tz) anesthetic combination was evaluated in 10 Dorset-type ewes. Ewes were randomly allotted to 2 equal groups. Ewes of groups 1 and 2 were given a single bolus of tz (12 and 24 mg/kg of body weight, iv, respectively) at time zero. Hemodynamic, pulmonary, and ventilation variables were measured at 15-minute intervals to 120 minutes. Blood gas variables were evaluated at 5-minute intervals for the first 30 minutes, then at 15-minute intervals to 120 minutes. In all sheep, tz administration induced rapid, smooth induction, with gradual and unremarkable recovery. Anesthesia duration was not significantly different between groups (mean ± sd, 39 ± 5 and 40 ± 14 minutes for groups 1 and 2, respectively). Immediate drug effects included apnea, decreased mean arterial blood pressure, and arterial hypoxemia. Cardiac output was significantly decreased in both groups at all times after drug administration. Significant changes in group-1 ewes included increased pulmonary and systemic vascular resistances and decreased inspired minute ventilation, tidal volume, and respiratory airflow. Significant changes in group-2 ewes included increased systemic vascular resistance and decreased pulmonary arterial pressure, inspired minute ventilation, and respiratory airflow. Both drug dosages induced apneustic breathing patterns and caused significant changes in arterial and venous blood hemoglobin concentrations and pcv. Tiletamine-zolazepam is useful for intermediate-duration anesthesia in sheep. However, because of alterations in cardiopulmonary function, its use at the dosages evaluated by us is not recommended in studies, in which minimal effects on heart and lung function are required, or in sheep with compromised heart or lung function.

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in American Journal of Veterinary Research

Summary

The effect of postnatal acid-base status on the absorption of colostral immunoglobulins by calves was examined in 2 field studies. In study 1, blood pH at 2 and 4 hours after birth was related to serum IgG1 concentration 12 hours after colostrum feeding (P < 0.05). Decreased IgG1 absorption from colostrum was associated with respiratory, rather than metabolic, acidosis, because blood PCO2 at 2 and 4 hours after birth was negatively related to IgG1 absorption (P < 0.05), whereas serum bicarbonate concentration was not significantly related to IgG1 absorption.

Acidosis was frequently observed in the 30 calves of study 1. At birth, all calves had venous PCO2 value ≥ 60 mm of Hg, 20 of the calves had blood pH < 7.20, and 8 of the calves had blood bicarbonate concentration < 24 mEq/L. Blood pH values were considerably improved by 4 hours after birth; only 7 calves had blood pH values < 7.20.

Calves lacking risk factors for acidosis were examined in study 2, and blood pH values at 4 hours after birth ranged from 7.25 to 7.39. Blood pH was unrelated to IgG1 absorption in the calves of study 2. However, blood PCO2 was again found to be negatively related to colostral IgG1 absorption (P < 0.005).

Results indicate that postnatal respiratory acidosis in calves can adversely affect colostral immunoglobulin absorption, despite adequate colostrum intake early in the absorptive period.

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in Journal of the American Veterinary Medical Association