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Summary

Management practices of 53 beef cow-calf producers were surveyed by use of a mail questionnaire. Producers were randomly selected from those who employ veterinarians to perform herd pregnancy examinations. Questions were asked about animal management, grazing and feeding, vaccination, and record-keeping practices. Median herd size was 250 breeding cows, and 2,329 of 2,491 (93.5%) randomly sampled cows in these herds were pregnant. Less than half of producers associated with these herds reported adoption of many beneficial practices related to bull management, infectious disease management, nutrition, and individual-animal record keeping, suggesting that a considerable number of producers are missing opportunities to optimize production and, thus, economic return. Use of individual-animal production records, which would enable more objective decision making on the basis of production and economic data, was not widespread. These findings suggested that veterinarians serving beef ranches have opportunities to provide additional services incorporating these management practices.

Free access
in Journal of the American Veterinary Medical Association

Summary

In 228 clinically normal cows with a palpable corpus luteum 20 to 40 days after parturition and a mean 305-day mature equivalent milk production of 8,970 kg, prostaglandin F was administered in a randomized, controlled clinical trial to determine whether such treatment enhanced their subsequent reproductive performance. Although the treatment reduced median time to first breeding by 4.5 days (P = 0.0025) from 57.0 days, median time to conception was not significantly different between the treatment and nontreated control group (87.0 vs 88.5 days) and conception rate by 110 days after parturition was not significantly different (64.7 vs 69.6%). Use of prostaglandin was associated with a significant (P = 0.0459) decrease in conception rate at first breeding from 42.0 to 29.3%. This study suggested that prostaglandin treatment of cows with a normal reproductive tract and a palpable corpus luteum at a median of 25 days after parturition does not enhance their reproductive performance and thus is not cost-effective.

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine the minimal ultrasonic aspirator pressure necessary to damage the cerebral cortex of healthy dogs.

Animals—9 mixed-breed dogs.

Procedure—The study comprised 2 parts. In part A, 6 dogs were euthanatized immediately prior to the experiment. In part B, 3 dogs were anesthetized for recording of physiologic variables. In both parts, craniectomy and durotomy were performed to bilaterally expose the lateral aspect of the cerebral cortex. An ultrasonic aspirator was placed in contact with various areas of the cerebral cortex, and aspirator power was altered (10, 20, 30, and 40%). Duration of contact at each power was 5 and 10 seconds. Subsequently, gross morphologic and histologic damage was assessed in the cortex.

Results—Gross observations for all dogs were similar. At 10% power, visible or histologic damage was not evident in the cortex. At 20% power, the cortex was slightly indented from contact with the hand piece; however, cortical disruption was not evident. Cortical disruption was initially detectable at 30% power in some dogs and was consistently evident at 40% power in both sets of dogs.

Conclusions and Clinical Relevance—Ultrasonic aspirator power of < 20% created minimal acute morphologic damage to the cortex. Power settings between 20 and 30% may superficially damage the cerebral cortex in healthy dogs, whereas 40% power consistently damages the cerebral cortex. Knowledge of the degree of damage to cerebral cortex caused by various amounts of power for ultrasonic aspirators will allow surgeons to avoid damaging normal brain tissues during surgery. (Am J Vet Res 2001;62: 248–251)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To compare bursting pressures in canine jejunum, measured by use of an in vitro and an in situ bursting pressure technique.

Study Population—Cadavers of 3 healthy adult dogs.

Procedures—54 enterotomies were performed on 3 canine cadavers immediately after euthanasia. After completion of enterotomy closure, bursting pressure was measured on 9 jejunal segments by use of an in situ technique and on 9 jejunal segments by use of an in vitro technique for each canine cadaver. Bursting pressure testing time was recorded for both in situ and in vitro techniques. Techniques were compared by means of randomized block ANOVA.

Results—The mean ± SE in vitro and in situ bursting pressures were 93.63 ± 24.10 mm Hg and 141.19 ± 38.10 mm Hg and were not significantly different. Mean in situ testing time was 40.7 min/cadaver; mean in vitro testing time was 50.3 min/cadaver.

Conclusions and Clinical Relevance—The in situ bursting pressure testing technique yielded results similar to those of the in vitro method, was somewhat less labor-intensive, and may be applicable to future studies of live dogs.

Full access
in American Journal of Veterinary Research

SUMMARY

The performance of the serum complement fixation (cf) test was compared with that of a serum agar gel immunodiffusion (agid) test on 74 subclinically infected and 154 uninfected cattle in 6 commercial midwestern dairy herds with Mycobacterium paratuberculosis infection and on 30 cattle in a herd that was free of infection. Infection status of cattle within herds was established by performance of a series of 3 or more fecal cultures and of ileocecal lymph node cultures of culled cattle.

In cattle with subclinical infection detected by culturing, the sensitivity estimates of the cf and agid tests were 10.8% (3.6% se) and 18.9% (4.5% se), respectively, In the cattle classified as disease free, the specificity estimates of the cf and agid tests were 97.4% (1.3% se) and 99.4% (0.6% se), respectively. Neither set of estimates was significantly different.

Negative test results obtained with the use of either test in apparently normal cattle from suspect herds should be interpreted with caution because both tests suffer from how sensitivities in subclinically infected animals. However, the agid test may be more useful in regulatory situations in which the cf test is currently used because the agid test is easier to perform and to interpret.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To determine the incidence of and risk factors for postoperative regurgitation and vomiting (PORV) in dogs.

Design—Retrospective cohort study.

Animals—244 client-owned dogs.

Procedures—Dogs referred for nonelective surgery in the first 3 months of 2000 and 2012 were included. Breed; sex; age; weight; body condition score; emergency status; food withholding status; history of vomiting or regurgitation; American Society of Anesthesiologists score; presence of diabetes or hypothyroidism; preoperative PCV and total solids concentration; anesthesia protocol; corticosteroid, opioid, neuromuscular blocking agent, and nitrous oxide usage; anesthesia time; surgery time; type of surgery; and occurrence of vomiting or regurgitation within 24 hours after recovery from anesthesia were recorded. Data were analyzed by means of the Fisher exact test, Wilcoxon rank sum test, and logistic regression.

Results—30 of 244 (12.3%) dogs meeting study inclusion criteria developed PORV. There was no significant difference in the incidence of PORV between the 2000 (12/111 [10.8%]) and 2012 (18/133 [13.5%]) cohorts, although the incidence of regurgitation was higher in 2012. Univariate logistic regression identified the most significant risk factors as gastrointestinal surgery (OR, 11.15; 95% confidence interval [CI], 3.11 to 40.03), premedication without strong sedatives including either an α2-adrenoceptor agonist or acepromazine (OR, 5.36; 95% CI, 1.89 to 15.17), American Society of Anesthesiologists score of 4 (OR, 5.25; 95% CI, 1.05 to 26.15), history of vomiting or regurgitation (OR, 5.12; 95% CI, 1.83 to 14.31), emergency surgery (OR, 4.08; 95% CI, 1.29 to 12.90), neurologic surgery (OR, 3.18; 95% CI, 1.02 to 9.92), sevoflurane inhalation anesthesia (OR, 2.78; 95% CI, 1.25 to 6.13), and being sexually intact (OR, 2.37; 95% CI, 1.07 to 5.27). Multivariate analysis was not clinically useful owing to the low sensitivity and specificity of the model.

Conclusions and Clinical Relevance—Between 2000 and 2012, there was no change in the incidence of PORV for dogs undergoing neurologic, orthopedic, and soft tissue surgical procedures; however, the proportion of dogs that regurgitated increased significantly in 2012. Preoperative antiemetic prophylaxis should be considered in dogs undergoing gastrointestinal surgery and in those in which other risk factors are present.

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine whether Border Collies (ATP binding cassette subfamily B1 gene [ABCB1] wildtype) were more likely than other breeds to develop vincristine-associated myelosuppression (VAM) and, if so, whether this was caused by a mutation in ABCB1 distinct from ABCB1-1Δ.

Animals—Phase 1 comprised 36 dogs with the ABCB1 wildtype, including 26 dogs with lymphoma (5 Border Collies and 21 dogs representing 13 other breeds) treated with vincristine in a previous study; phase 2 comprised 10 additional Border Collies, including 3 that developed VAM and 7 with an unknown phenotype.

Procedures—For phase 1, the prevalence of VAM in ABCB1-wildtype Border Collies was compared with that for ABCB1-wildtype dogs of other breeds with data from a previous study. For phase 2, additional Border Collies were included. Hematologic adverse reactions were graded with Veterinary Co-operative Oncology Group criteria. Genomic DNA was used to amplify and sequence all 27 exons of the canine ABCB1. Sequences from affected dogs were compared with those of unaffected dogs and dogs of unknown phenotype.

Results—3 of 5 Border Collies with the ABCB1 wildtype developed VAM; this was significantly higher than the proportion of other dogs that developed VAM (0/21). A causative mutation for VAM in Border Collies was not identified, although 8 single nucleotide polymorphisms in ABCB1 were detected.

Conclusions and Clinical Relevance—Breed-associated sensitivity to vincristine unrelated to ABCB1 was detected in Border Collies. Veterinarians should be aware of this breed predisposition to VAM. Causes for this apparent breed-associated sensitivity should be explored.

Full access
in American Journal of Veterinary Research

Objective

To evaluate commingled grazing on public lands as a risk factor for Tritrichomonas foetus infection in beef herd bulls.

Design

Case-control study.

Sample Population

Based on 1994 data from the mandatory ldaho bull testing program, all 65 infected herds (case herds), 78 randomly selected test-negative herds that tested < 10 nonvirgin bulls, and 81 randomly selected test-negative herds that tested > 10 nonvirgin bulls (control herds).

Procedure

Managers of government-owned grazing lands in Idaho identified producers who had grazing permits for an allotment under their jurisdiction in 1993 and for that allotment recorded the number of animals the producer was permitted to graze on the allotment, the number of herds with grazing permits, the total number of animals permitted, and the dates on which grazing began and ended. The number of bulls tested, number of times tested, and test results were collated from the testing database.

Results

The relative sensitivity of bacterial culture of preputial smegma was 81%. The attributable fraction of T foetus infection associated with commingled grazing was 33%, and the odds ratio of infection was 9.0 for herds commingled with ≥ 14 other herds. The total number of animals permitted on an allotment, the use of public lands, and type of public lands used were not significantly associated with infection status.

Clinical Implications

These results suggest that to control the spread of trichomonosis, the number of herds commingling on a grazing allotment should be minimized and commingled herds should be managed collectively. (J Am Vet Med Assoc 1996;209:643-646)

Free access
in Journal of the American Veterinary Medical Association

Abstract

Muscle potentials evoked by stimulation of the sciatic nerve were evaluated in 4- and 15-week-old chickens. Each bird was anesthetized and slowly cooled externally from a normal body temperature of 40 C to 28 C, and motor nerve conduction velocities were measured at various intervals during cooling. Motor nerve conduction velocity decreased linearly with decreasing limb temperature in both groups. The rate of change in motor nerve conduction velocity per degree in 2 groups (2.13 m/s/C vs 1.84 m/s/ C) fell just short of a statistically significant difference (P = 0.0508), indicating that an age-related effect on temperature-associated variation in motor nerve conduction velocity may be present.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To compare plasma disposition of alkaloids after lupine challenge in cattle that had given birth to calves with lupine-induced arthrogryposis and cattle that had given birth to clinically normal calves and determine whether the difference in outcome was associated with differences in plasma disposition of anagyrine.

Animals—6 cows that had given birth to calves with arthrogryposis and 6 cows that had given birth to clinically normal calves after being similarly exposed to lupine during pregnancy.

Procedure—Dried lupine (2 g/kg) was administered via gavage. Blood samples were collected before and at various time points for 48 hours after lupine administration. Anagyrine, 5,6-dehydrolupanine, and lupanine concentrations in plasma were measured by use of gas chromatography. Plasma alkaloid concentration versus time curves were generated for each alkaloid, and pharmacokinetic parameters were determined for each cow.

Results—No significant differences in area under the plasma concentration versus time curve, maximum plasma concentration, time to reach maximum plasma concentration, and mean residence time for the 3 alkaloids were found between groups.

Conclusions and Clinical Relevance—Because no differences were found in plasma disposition of anagyrine following lupine challenge between cattle that had given birth to calves with arthrogryposis and those that had not, our findings do not support the hypothesis that between-cow differences in plasma disposition of anagyrine account for within-herd differences in risk for lupine-induced arthrogryposis. (Am J Vet Res 2004;65:1580–1583)

Full access
in American Journal of Veterinary Research