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Abstract

OBJECTIVE To describe disorders of performance-age bucking bulls.

DESIGN Retrospective case-control study.

ANIMALS 78 bucking (cases) and 236 nonbucking (controls) beef bulls.

PROCEDURES The medical record database of a referral hospital was reviewed to identify beef bulls > 1 year old that were examined for a medical or musculoskeletal disorder between January 1, 2000, and April 1, 2014. Bucking bulls were designated as cases, and nonbucking bulls were designated as controls. For each bull, the signalment, history, physical examination and diagnostic test results, and clinical diagnosis were recorded. The frequency of each disorder was compared between cases and controls.

RESULTS Fifteen of 78 (19%) cases and 132 of 236 (56%) controls had medical disorders; however, the frequency did not differ between the 2 groups for any medical disorder. Musculoskeletal disorders were identified in 55 (70.5%) cases and 109 (46%) controls. Cases were 10.55 times as likely as controls to have horn and sinus disorders. Of the 43 (55%) cases examined because of lameness, the thoracic limb was affected in 19 (44%). Compared with controls, cases were 13.37 and 3.31 times as likely to have a musculoskeletal disorder of the vertebral region and pelvic limb, respectively.

CONCLUSIONS AND CLINICAL RELEVANCE Results indicated bucking bulls were more likely than nonbucking bulls to develop horn and sinus disorders and musculoskeletal disorders of the vertebral region and pelvic limbs. The limb distribution of lameness for bucking bulls may differ from that for nonbucking bulls.

Full access
in Journal of the American Veterinary Medical Association

Abstract

OBJECTIVE To estimate survival time for dogs with small intestinal adenocarcinoma (SIACA) following tumor excision with or without adjuvant chemotherapy and to identify factors associated with survival time.

DESIGN Retrospective case series with a nested cohort study.

ANIMALS 29 client-owned dogs with surgically resected, histologically diagnosed SIACA.

PROCEDURES Medical records were reviewed and data collected regarding dog signalment; clinical signs; physical examination findings; PCV; serum total solids concentration; diagnostic imaging results; tumor size, location, and histologic characteristics (serosal extension, lymphatic invasion, surgical margins, and lymph node metastasis); type of adjuvant chemotherapy; NSAID administration; and survival time. Variables were assessed for associations with survival time and hazard rate via Kaplan-Meier and Cox proportional hazards analyses.

RESULTS Overall median survival time for dogs with SIACA following tumor excision was 544 days (95% confidence interval, 369 to 719 days). Based on Kaplan-Meier estimates, the 1- and 2-year survival rates were 60% and 36%, respectively. On multivariate analysis, only age category was an independent predictor of survival over the follow-up period. Dogs < 8 years of age had a significantly longer median survival time (1,193 days) than dogs ≥ 8 years (488 days). Lymph node metastasis, adjuvant chemotherapy, NSAID administration, and other assessed variables were not associated with survival time.

CONCLUSIONS AND CLINICAL RELEVANCE Findings suggested that SIACA in dogs carries a fair prognosis following excision, even when lymph node metastasis is present. Prospective studies are warranted to better characterize the effects of adjuvant chemotherapy or NSAID administration on survival time.

Full access
in Journal of the American Veterinary Medical Association

SUMMARY

A sublethal dose of ethylene glycol was administered orally to 3 groups of dogs; dogs of a control group were given distilled water instead. Renal cortical biopsy samples were obtained from dogs of experimental and control groups at various times after treatment. Tissue was examined by use of light microscopy and transmission electron microscopy. In dogs of the control group, the light and electron microscopic appearances of tissue were within normal limits at all sample collection hours. In dogs of the experimental groups, renal corpuscular structure remained within normal limits by use of light and electron microscopy throughout the study, though morphologic change was seen in other structures of the cortex. Light microscopic lesions first appeared at 12 hours, and were similar to those reported in the literature. Ultrastructural lesions were first observed in the 5-hour samples, and similar to the light microscopic lesions, were most common in the proximal convoluted tubules (pct). Initial pct cellular changes included vacuolization of cells and distention of the parabasal extracellular spaces; pct cellular lesions seen in later-hour samples included formation of apical buds and cellular rupture. Internalization or sloughing of the pct brush border was not observed. Distal convoluted tubules (dct) were frequently dilated and/or packed with cellular debris. A few dct cells had degenerative or necrotic changes. In pct and dct, abnormal cells were frequently flanked by normal or nearly normal cells. During later hours, a few cells with types of changes first observed in early hours continued to be observed, implying ongoing response of cells to the toxin.

Free access
in American Journal of Veterinary Research

SUMMARY

Naturally acquired gram-negative bacterial intramammary infections (n= 160) were studied in 99 cows over a 2-year period. Escherichia coli, Klebsiella spp, Serratia spp, Enterobacter spp, and unidentified gram-negative bacteria were isolated from 28.8, 39.4, 9.4, 5.0, and 11.2%, respectively, of infected mammary glands. A majority (61%) of intramammary infections were first detected during the nonlactating period. Gram-negative bacteria isolated during the first half of the nonlactating period were predominantly Klebsiella spp, Serratia spp, and Enterobacter spp. Onset of E coli intramammary infections was more prevalent during the second half of the nonlactating period and during the first 7 days of lactation. The majority (59%) of infections were < 28 days in duration, but Klebsiella spp and Serratia spp infections were of significantly (P < 0.05) greater duration than infections with E coli. The greatest percentage (47%) of gram-negative bacterial intramammary infections were first detected during the summer.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate trends in feedlot cattle mortality ratios over time, by primary body system affected, and by type of animal.

Design—Retrospective cohort study.

Animals—Approximately 21.8 million cattle entering 121 feedlots in the United States during 1994 through 1999.

Procedures—Yearly and monthly mortality ratios were calculated. Numbers of deaths were modeled by use of Poisson regression methods for repeated measures. Relative risks of death over time and by animal type were estimated.

Results—Averaged over time, the mortality ratio was 12.6 deaths/1,000 cattle entering the feedlots. The mortality ratio increased from 10.3 deaths/1,000 cattle in 1994 to 14.2 deaths/1,000 cattle in 1999, but this difference was not statistically significant (P = 0.09). Cattle entering the feedlots during 1999 had a significantly increased risk (relative risk, 1.46) of dying of respiratory tract disorders, compared with cattle that entered during 1994, and respiratory tract disorders accounted for 57.1% of all deaths. Dairy cattle had a significantly increased risk of death of any cause, compared with beef steers. Beef heifers had a significantly increased risk of dying of respiratory tract disorders, compared with beef steers.

Conclusions and Clinical Relevance—Results suggested that although overall yearly mortality ratio did not significantly increase during the study, the risk of death attributable to respiratory tract disorders was increased during most years, compared with risk of death during 1994. The increased rates of fatal respiratory tract disorders may also reflect increased rates of non-fatal respiratory tract disorders, which would be expected to have adverse production effects in surviving animals. (J Am Vet Med Assoc 2001;219:1122–1127)

Full access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine effects of sedation achieved by xylazine (XYL) or acepromazine (ACE) on cardiopulmonary function and uterine blood flow in cows in late gestation.

Animals—8 cows between 219 and 241 days of gestation.

Procedure—Doses of ACE (0.02 mg/kg) or XYL (0.04 mg/kg) were administered IV. Measurements were obtained to determine cardiopulmonary effects and oxygen delivery to the uterus.

Results—Heart rate was not significantly affected by administration of ACE, but it decreased markedly after administration of XYL. Uterine artery flow was decreased at all times by XYL and was always less than for ACE. Xylazine increased uterine vascular resistance through 30 minutes and caused reduced PaO2 and increased PaCO2 at all time periods. Acepromazine caused a 5% decrease in PaO2 only at 5 minutes. Xylazine reduced oxygen delivery by 59% at 5 minutes and 32% at 45 minutes. In contrast, ACE caused a nonsignificant reduction of oxygen delivery by 16% at 15 minutes and a return to baseline values by 45 minutes

Conclusions and Clinical Relevance—Xylazine markedly reduces flow and availability of oxygenated blood to the uterus, which may critically impair delivery of oxygen to the fetus at a stressful and important time of development or delivery. Acepromazine was associated with slight reductions of much shorter duration. When XYL is used to sedate pregnant cows, it could impose physiologic distress on the fetus and potentially increase fetal morbidity and mortality. When sedation of the dam is desirable, ACE could be an alternative to XYL. (Am J Vet Res 2002;63:1695–1699)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate epidemiologic features of rabies virus variants in dogs and cats in the United States during 1999 and assess the role of bat-associated variants.

Design—Epidemiologic survey.

Sample Population—Rabies viruses from 78 dogs and 230 cats.

Procedure—Brain specimens from rabid dogs and cats were submitted for typing of rabies virus. Historical information, including ownership and vaccination status, was obtained for each animal. Specimens were typed by use of indirect fluorescent antibody assay or reverse transcriptase polymerase chain reaction assay and nucleotide sequence analysis.

Results—Nearly all animals were infected with the predicted terrestrial rabies virus variant associated with the geographic location of the submission. A batassociated variant of rabies virus was found in a single cat from Maryland. More than half (53%) of submitted animals were classified as owned animals, and most had no known history of vaccination. One vaccination failure was reported in a dog that did not receive a booster dose of rabies vaccine after exposure to a possibly rabid animal.

Conclusions and Clinical Relevance—Bat-associated rabies virus variants were not a common cause of rabies in dogs and cats during 1999. Vaccine failures were uncommon during the study period. Because most rabid dogs and cats were unvaccinated and were owned animals rather than strays, educational campaigns targeting owners may be useful. (J Am Vet Med Assoc 2001;218:1939–1942)

Full access
in Journal of the American Veterinary Medical Association

Summary:

The effects of propofol on anesthetic induction were evaluated in 40 dogs anesthetized with isoflurane. Propofol is a rapidly acting, nonbarbiturate drug that induces anesthesia of ultrashort duration with iv administration. Four preanesthetic regimens were used: anesthesia without preanesthetic drugs; or with preanesthetic administration of acepromazine (0.1 mg/kg of body weight, im), diazepam (0.2 mg/kg, iv), or acepromazine (0.02 mg/kg) and butorphanol (0.4 mg/kg) im. Heart rate, systolic arterial blood pressure (sap), respiration, quality of induction and recovery, and adverse effects were recorded. Intravenous propofol administration induced a variable period of apnea in 34 of 40 dogs. Cyanosis (in 2 dogs) and signs of pain on injection (in 3 dogs) were infrequently observed during induction. One dog developed ventricular premature depolarizations after propofol administration. Venous CO2 tension increased and pH decreased immediately after propofol administration, regardless of preanesthetic regimen. The sap significantly (P < 0.05) decreased after propofol administration in dogs treated with acepromazine (sap, 178 mm of Hg before vs 128 mm of Hg after propofol) and with acepromazine/butorphanol (sap, 184 mm of Hg before vs 98 mm of Hg after propofol). When used for induction, propofol induces anesthetic-related adverse effects, some of which can be minimized by preanesthetic medication. Recovery characteristics varied with preanesthetic medication, independent of propofol administration.

Free access
in Journal of the American Veterinary Medical Association

Summary

A murine IgM monoclonal antibody, which recognizes dog erythrocyte antigen (dea) 1.1, has been produced. The antibody correctly identified canine rbc possessing dea 1.1 in a panel of rbc typed by an independent laboratory. Reactivity of the monoclonal antibody was compared with canine anti-dea 1.1 antiserum with 163 rbc samples from 145 dogs. Results of agglutination tests with the 2 reagents were in agreement for all samples. A card agglutination test that uses the monoclonal antibody with blood is described. A monoclonal antibody-based test should facilitate blood typing for dea 1.1 in clinical practice.

Free access
in Journal of the American Veterinary Medical Association