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Abstract

Objective—To determine risk factors associated with identification of an umbilical hernia during the first 2 months after birth in Holstein heifers.

Design—Case-control study.

Animals—322 Holstein heifers born in a single herd (45 with an umbilical hernia and 277 without).

Procedure—Risk factors that were examined included sire, whether the dam had a history of umbilical hernia, milk yield, duration of gestation, whether the dam had a history of dystocia, whether the heifer had a twin, birth weight, total serum protein concentration, and whether the heifer had an umbilical infection. Logistic regression was used to analyze risk factors.

Results—Heifers born to sires with ≥ 3 progeny with an umbilical hernia were 2.31 times as likely to develop an umbilical hernia as were heifers born to sires with ≤ 2 progeny with an umbilical hernia. Heifers with umbilical infection were 5.65 times as likely to develop an umbilical hernia as were heifers without umbilical infection.

Conclusions and Clinical Relevance—Sire and umbilical infection were associated with risk of an umbilical hernia during the first 2 months of life in Holstein heifers. Attributable proportion analysis indicated that the frequency of umbilical hernias in Holstein heifers with umbilical infection would have been reduced by 82% if umbilical infection had been prevented. (J Am Vet Med Assoc 2004;224:1487–1490)

Full access
in Journal of the American Veterinary Medical Association

Objective—

To evaluate differences in milk production between cows with positive and negative caudal fold tuberculin test results in a Mycobacterium bovis-infected dairy herd.

Design—

Cross-sectional epidemiologic survey.

Animals—

369 Holstein cows with lactation duration between 200 and 360 days.

Procedure—

The caudal fold tuberculin test was performed. Information on milk production data, parity, calving season, days of lactation, previous milk production, and whether cows had clinical mastitis was obtained from farm records. Composite milk samples were collected and submitted for bacterial culture.

Results—

170 cows had positive tuberculin test results, and 199 had negative results. Cows with positive test results produced less milk (mean, 347 kg [763 lb]) than did cows with negative test results after adjusting for variables biologically related to milk production. Calving season (spring, summer) was significantly associated with reduced milk production. Cows with clinical mastitis produced less milk than did cows without clinical mastitis, but the difference was not statistically significant in the multiple regression analysis.

Clinical Implications—

In this herd, tuberculosis was associated with a 4% decrease in milk production. Milk production losses per cow attributable to calving season (spring, summer) were 3 times those attributable to tuberculosis. However, because of the high prevalence of tuberculosis in this herd, the impact of tuberculosis on total herd milk production was an additional cause for concern. (J Am Vet Med Assoc 1998;213:851-854)

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To compare financial returns between pinhooked yearling horses (ie, bought and trained for approximately 5 months with the goal of selling the horse at "2-year-olds in training" sales) that had mild or severe training failure and horses that had planned versus nonplanned training failure.

Animals—40 Thoroughbred pinhooked yearling horses.

Procedure—During the period from September 1998 through and April 1999, 20 horses had mild training failure (1 to 11 days lost), and 20 horses had severe training failure (13 to 108 days lost). Horses were assigned to these 2 groups on the basis of frequency distribution (median) of days lost during training. Horses were also categorized on the basis of type of training failure (planned vs nonplanned training failure). The outcome of primary interest was financial return. Median financial returns were compared among groups by use of the Mann-Whitney U test.

Results—Median financial returns for horses that had severe training failure ($1,000) were significantly different, compared with horses that had mild training failure ($24,000). Analysis of results also indicated that median returns were significantly different among horses that had planned training failure (−$2,000; eg, horses with radiographic abnormalities detected during routine prepurchase examinations that required surgical treatment, resulting in days lost during training), compared with horses that did not ($10,000).

Conclusions and Clinical Relevance—Training failure has an economic impact on revenues in pinhooked yearling horses. Lameness, planned training failure, respiratory disease, and ringworm were common and important causes of training failure. (Am J Vet Res 2001;62:1418–1422)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate efficacy of topical treatment with oxytetracycline solution among dairy cows with papillomatous digital dermatitis (PDD) lesions on the interdigital cleft, heels, or dewclaw.

Design—Clinical trial.

Animals—70 dairy cows from a single herd.

Procedure—On the basis of anatomic location of PDD lesions, cows were allocated into 1 of 3 groups (interdigital cleft [n = 14], heels [30], or dewclaw [26]) and treated topically with oxytetracycline solution. Cows were examined 14 and 30 days after initial treatment. During each examination, pain and lesion size scores were recorded.

Results—On the basis of pain and lesion size scores, oxytetracycline appeared significantly less effective among cows with lesions on the interdigital cleft than for cows with lesions on the heels or the dewclaw. Number of cows with signs of pain or visible lesions after treatment was significantly higher for cows with lesions on the interdigital cleft than for cows with lesions on heels or the dewclaw.

Conclusions and Clinical Relevance—Anatomic location of PDD lesions has an effect on the efficacy of topical treatment with oxytetracycline solution in dairy cows affected with PDD. Cows with lesions on the interdigital cleft were less likely to respond to treatment, compared with cows with lesions on the heels or the dewclaw. (J Am Vet Med Assoc 2000;216:1288–1290)

Full access
in Journal of the American Veterinary Medical Association

Objective

To compare prevalence estimates of brucellosis (BR) in adult beef cattle that originated from different states and regions of Mexico and that were shipped direct-to-slaughter into Texas during 1995.

Design

Epidemiologic survey.

Animals

About 65,000 adult beef cattle.

Procedure

Blood samples were collected during postmortem examinations and were tested for serum antibodies to Brucella abortus, using the particle concentration fluorescence immunoassay and automated complement-fixation test. Prevalence estimates and 95% confidence intervals of BR were calculated by state of origin in Mexico. The difference among prevalence estimates of BR in cattle from different states and regions was tested for significance (P< 0.05), using the proportion test.

Results

On the basis of serologic test results, the overall prevalence estimate of BR was 0.32%. The prevalence estimate of BR in cattle from the state of Chihuahua (0.10%) was significantly different than that in cattle from the states of Nuevo Leon (0.23%), Zacatecas (0.34%), Durango (0.47%), Chiapas (1.81%), Tamaulipas (2.71%), Aguascalientes (7.89%), and Campeche (12.24%). In addition, prevalence estimates of BR in cattle were significantly different among the northern (0.22%), south-central (3.18%), and south coastal (9.42%) regions of Mexico.

Clinical Implications

Results of this study indicate that the number of cattle exposed to B abortus may be significantly different among states and regions of Mexico. Current import sanitary requirements should continue to mitigate potential risk of transmission of BR from sexually intact cattle of Mexican origin to Texas cattle. (J Am Vet Med Assoc 1998; 212:705-707)

Free access
in Journal of the American Veterinary Medical Association

Objective

To evaluate differences in prevalence of tuberculosis (TB) in adult beef cattle that originated from different states in Mexico and were shipped direct-to-slaughter into Texas in 1995.

Design

Epidemiologic survey.

Animals

Approximately 65,000 adult beef cattle.

Procedures

Postmortem examinations of carcasses for detection of Mycobacterium bovis infection were conducted at slaughter plants in Texas. Specimens were collected from cattle with granulomatous lesions, stored in neutral-buffered 10% formalin or saturated sodium borate solution, and processed for histologic and bacteriologic diagnosis. Prevalence and 95% confidence intervals were estimated by state of origin. Difference between prevalences for different states was tested for significance (P< 0.05), using the proportion test.

Results

Overall prevalence of TB at slaughter in adult beef cattle that originated from Mexico was approximately 0.5/1,000 (34/65,233). Prevalence of TB in cattle that originated from Chihuahua (0.07) was significantly lower than that in cattle from Coahuila (0.80), Nuevo Leon (1.27), and Tamaulipas (1.81).

Clinical Implications

Prevalence of M bovis infection in adult beef cattle may be significantly different between states in the northern border region of Mexico. On the basis of disease prevalence and numbers of exported cattle and provided safeguards such as TB testing are continued, cattle from Chihuahua may pose a lower risk of TB transmission to Texas cattle than do cattle from Coahuila, Nuevo Leon, and Tamaulipas. To allow interstate/international movement of cattle from northern border states of Mexico, TB testing requirements should be continued. In the context of international trade, southern border states of the United States should continue collaborating with northern border states of Mexico to control and eradicate this disease. (J Am Vet Med Assoc 1998; 212:557-559)

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To examine the relationship between lameness and milk yield in dairy cows.

Design—Cohort study.

Animals—531 dairy cows.

Procedure—Cows affected with lameness were classified into 1 of 3 groups on the basis of type of diseases or lesions observed, including interdigital phlegmon (foot rot), papillomatous digital dermatitis (foot warts), or claw lesions. Cows not affected with lameness were classified as healthy. From Dairy Herd Improvement Association records, 305-day mature equivalent milk yield data were collected at the end of lactation or when the cow left the herd. Milk yield was compared between cows affected with lameness and healthy cows.

Results—167 (31%) cows were affected with lameness during lactation. Lame cows had claw lesions (60%), papillomatous digital dermatitis (31%), or interdigital phlegmon (9%). Milk yield in lame cows with interdigital phlegmon (mean, 17,122 lb) was significantly less, compared with healthy cows (19,007 lb).

Conclusions and Clinical Relevance—In this herd, interdigital phlegmon was associated with a 10% decrease in milk production. Lame cows with claw lesions or papillomatous digital dermatitis produced less milk than healthy cows, but the difference was not significant. (J Am Vet Med Assoc 2002;220:640–644)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To examine the relationship between exposure to Neospora caninum and abortion in dairy cows during their first, second, third, and fourth or later lactations and to establish the main mode of transmission in female calves from birth until their first pregnancy was terminated by abortion or parturition.

Design—Prospective observational study.

Animals—460 Holstein cows and 79 female calves.

Procedure—Cows were classified as seropositive or seronegative to N caninum within 7 days after calving; incidence of abortion was compared between groups during different lactations. Blood samples were collected from female calves before ingestion of colostrum and every 6 months until their first pregnancy was terminated by abortion or parturition; number of seropositive calves was compared between seropositive and seronegative dams.

Results—During the first pregnancy of their second lactation, risk of abortion for seropositive cows was 2.8 times that of seronegative cows. Among 10 calves born to seropositive cows, 4 were classified as seropositive at birth and thereafter. Among 69 calves born to seronegative cows, all were classified as seronegative at birth; 67 calves remained seronegative thereafter.

Conclusions and Clinical Relevance—Exposure to N caninum alone was not significantly associated with abortion in cows during the first, third, and fourth or later lactations. Seropositive cows that have aborted previously may have subsequent abortions attributable to N caninum. Congenital infection was the main mode of N caninum transmission in a cohort of female calves. (J Am Vet Med Assoc 2002;221:1742–1746)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To identify race-start characteristics associated with catastrophic musculoskeletal (MS) injury in Thoroughbred racehorses at 2 racetracks in Florida during 1995 through 1998.

Design—Matched case-control study.

Animals—97 Thoroughbreds (case horses) that incurred a catastrophic MS injury during racing and 388 Thoroughbreds (control horses) randomly selected from noninjured participants and matched on the basis of racetrack and year.

Procedure—Incidence of MS injury was calculated for all race meets at 2 racetracks in Florida from 1995 through 1998. Race-start characteristics were compared among case and control horses, using conditional logistic regression.

Results—Overall incidence of MS injury was 1.2/1,000 race starts (97/79,416 starts). Incidence of injury was significantly higher for turf races (2.3/1,000 starts) than for dirt races (0.9/1,000 starts). Sex, number of days since last race, and racing surface were associated with risk of injury; geldings, ≥ 33 days since the last race, and turf racing surface were associated with a higher risk of injury.

Conclusions and Clinical Relevance—Incidence of injury among Thoroughbreds in Florida was associated with sex, number of days since last race, and racing surface. Days since last race may have been an indicator of previous health and lameness problems. Racing surface may have been a risk factor for MS injury because turf races tended to be more competitive than dirt races. Horses running in turf races were more likely to participate in races with a large field, handicap races, long races, and races with high purses. (J Am Vet Med Assoc 2001;218:83–86)

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in Journal of the American Veterinary Medical Association

Abstract

Objective—To examine the relationship between lameness and the duration of the interval from calving to subsequent conception in lactating dairy cows.

Design—Cohort study.

Animals—837 dairy cows.

Procedure—Cows affected with lameness were classified into 1 of 4 groups on the basis of types of disease or lesions observed, including foot rot, papillomatous digital dermatitis, claw lesions, or multiple lesions. Cows not affected with lameness were classified as healthy. Time from calving to conception was compared between lame cows and healthy cows.

Results—254 (30%) cows were affected with lameness during lactation. Most lame cows (59%) had claw lesions. Lame cows with claw lesions were 0.52 times as likely to conceive as healthy cows. Median time to conception was 40 days longer in lame cows with claw lesions, compared with healthy cows. Number of breedings per conception for lame cows with claw lesions was significantly higher than that for healthy cows.

Conclusion and Clinical Relevance—Claw lesions were the most important cause of lameness, impairing reproductive performance in dairy cows, as indicated by a higher incidence of affected cows and a greater time from calving to conception and a higher number of breedings required per conception, comp ared with healthy cows. (J Am Vet Med Assoc 2001; 218:1611–1614)

Full access
in Journal of the American Veterinary Medical Association