Biomedical subjects

J B Kaneene

Publications and source records attributed to J B Kaneene.

At least 37 records · Page 2Linked to original sources

PubMed2001

Enteric parasitosis in northern Thailand dairy heifers and heifer calves.

A cross-sectional study was designed to: (1) determine the prevalences of enteric parasitic infections in dairy heifers and heifer calves (Bos taurus) in northern Thailand, and (2) determine the risk factors associated with the observed prevalences of infection. A stratified random sample of 87 farms was selected for study, and fecal and blood samples were collected from 439 out of 450 heifers and heifer calves from these farms. Fecal samples were processed by floatation and modified Benedek sedimentation methods, and then examined microscopically for the presence of enteric parasitic ova. Complete blood counts typically were within the reference range (done using standard methods). The overall prevalence for enteric parasites in heifers and heifer calves was 54%; most were of trematodes (41%) and nematodes (26%). Risk-factors analysis at the farm level yielded no significant results. Increased age significantly increased the odds of enteric parasite infection (OR=1.02, 95% CI 1.01-1.04).

Animals↗

PubMed2001

Reliability of three bulk-tank antimicrobial residue detection assays used to test individual milk samples from cows with mild clinical mastitis.

OBJECTIVE: To determine the likelihood of false-positive results when testing milk samples from individual cows by use of 3 commercially available assays (Penzyme MilkTest and the SNAP beta-lactam and Delvo-SP assays) labeled for use with commingled milk. SAMPLE POPULATION: Milk samples from 111 cows with mild clinical mastitis. PROCEDURE: Cows were randomly assigned to the control (no antimicrobials) or intramammary treatment group. Posttreatment milk samples were collected at the first milking after the labeled withholding period or an equivalent time for controls, randomly ordered, and tested twice by use of each assay and once by use of high-performance liquid chromatography. Sensitivity, specificity, and positive and negative predictive values were determined for each assay. Concordance of results for the same sample was assessed for each assay by calculating kappa. RESULTS: Sensitivities of the Delvo-SP and SNAP lactam assays were > 90%, whereas the sensitivity of the Penzyme Milk Test was 60%. Positive predictive values (range, 39.29 to 73.68%) were poor for all 3 assays. Concordance of test results was excellent for the SNAP beta-lactam and Delvo-SP assays (kappa = 0.846 and 0.813, respectively) but was less for the Penzyme MilkTest (kappa = 0.545). CONCLUSIONS AND CLINICAL RELEVANCE: Because of the low positive predictive values, these 3 assays may not be useful for detecting violative antimicrobial residues in individual milk samples from cows treated for mild clinical mastitis. However, repeatability of each assay was considered good to excellent.

Animals↗

PubMed2001

The effect of subclinical Mycobacterium paratuberculosis infection on milk production in Michigan dairy cows.

The objective of this study was to determine the effect of subclinical Mycobacterium paratuberculosis infection on mature equivalent milk, protein, and fat production in a sample of Michigan dairy herds with a history of cows positive for M. paratuberculosis diagnosed by fecal culture. A prospective two-group cohort study was conducted. Participating herds were tested, and productivity and reproduction records were monitored for 18 mo. All cows aged 24 mo and greater were tested for M. paratuberculosis infection using the ELISA and radiometric fecal culture (RFC) techniques. Using both tests in parallel, the overall sample apparent prevalence for M. paratuberculosis infection was 41.8%. Adjusting for diagnostic sensitivity and specificity resulted in a calculated sample true prevalence of 59.9%. Subclinical paratuberculosis test-positive status had no statistically significant effect on mature equivalent milk, fat, or protein production. The results of this study concur with the findings of other studies, reporting that the magnitude and direction of the association between subclinical paratuberculosis infection and milk production depends upon the parity of the animal, stage of disease, and the stage in lactation being monitored. Assessment of the impact of subclinical paratuberculosis on milk production must consider the average parity of the sample population. In herds that have an average parity of 2 or less, subclinical paratuberculosis infection may have little impact on milk production.

Animals↗

PubMed2001

Bovine tuberculosis in free-ranging carnivores from Michigan.

During a survey of carnivores and omnivores for bovine tuberculosis conducted in Michigan (USA) since 1996, Mycobacterium bovis was cultured from lymph nodes pooled from six coyotes (Canis latrans) (four adult female, two adult male), two adult male raccoons (Procyon lotor), one adult male red fox (Vulpes vulpes), and one 1.5-yr-old male black bear (Ursus americanus). One adult, male bobcat (Felis rufus) with histologic lesions suggestive of tuberculosis was negative on culture but positive for organisms belonging to the Mycobacterium tuberculosis complex when tested by polymerase chain reaction. All the tuberculous animals were taken from three adjoining counties where M. bovis is known to be endemic in the free-ranging white-tailed deer (Odocoileus virginianus) population. There were two coyotes, one raccoon, one red fox, and one bobcat infected in Alpena county. Montmorency County had two coyotes and one raccoon with M. bovis. Two coyotes and a bear were infected from Alcona County. These free-ranging carnivores/omnivores probably became infected with M. bovis through consumption of tuberculous deer. Other species included in the survey were opossum (Didelphis virginiana), gray fox (Urocyon cinereoargenteus), and badger (Taxidea taxus); these were negative for M. bovis.

Animals↗

PubMed2000

Spatial and temporal comparison of selected cancers in dogs and humans, Michigan, USA, 1964-1994.

Our aim was to investigate the geographic and time distributions of some biologically similar neoplasms in dogs and humans living in Michigan, USA, between 1964 and 1994. Our objective was to describe and compare the patterns of cancer in the two species while assessing the strength and dependence of those patterns. In this retrospective, registry-based study, histologically confirmed incident human and canine cancer cases were mapped, and second-order (K function) spatial analysis and one-dimensional nearest neighbor temporal analysis were performed on residence addresses and dates of hospital discharge/diagnosis. Included in the study were all 528 incident cases of canine lymphosarcoma, mammary adenocarcinoma, melanoma and spindle-cell sarcomas diagnosed at a veterinary teaching hospital between 1964 and 1994 having residence addresses in Ingham, Oakland, and Wayne Counties; and a stratified random sample of 913 incident human cases of comparable cancers diagnosed during the same time period from the same counties. Results suggest that processes determining spatial aggregation of cases in dogs and humans were not independent of each other, did not act uniformly over different geographic areas, operated at spatial scales <2000 m regardless of species, and tend to act upon dogs more strongly at shorter distances than on humans. Little evidence of interspecies concurrence of temporal clustering was found.

Adenocarcinoma↗

PubMed2000

Augmentation of mercury-induced nephrotoxicity by endotoxin in the mouse.

Endotoxin (lipopolysaccharide; LPS) and mercury are compounds of food safety concern. Endotoxin is a product of cell walls of gram negative bacteria. Humans are constantly exposed to LPS through infection plus translocation into circulation from the gastrointestinal tract. Food is the major source of mercury in humans. The toxic interaction between LPS and mercury has not been well investigated. In a previous study, we demonstrated that LPS potentiated mercury-induced nephrotoxicity in the rat. Whether this observation was species specific was not clear. In this study we tested the hypothesis that LPS enhances mercuric chloride (HgCl(2))-induced nephrotoxicity in mice. In a 2x2 factorial design, mice received either Escherichia coli 0128:B12 endotoxin (2.0 mg/kg body weight) or 200 microliter of 0.9% sodium chloride (saline), and this was followed 4 h later by either mercury (1.75 mg mercuric chloride per kg body weight) or 200 microliter of saline. Mice were monitored for 48 h. Monitored end-points included body and renal weights, urine volume, renal histology and ultrastructural pathology, serum urea nitrogen and creatinine, selected serum and urine cytokines, and renal mercury concentrations. Endotoxin by itself was not nephrotoxic at the dose used in this study. Overall, mice given LPS plus mercury were the most severely affected. Mice given LPS and mercury also had significantly greater renal mercury concentration than those given mercury alone (P</=0.05). In conclusion, LPS potentiates mercury-induced nephrotoxicity in the mouse.

Animals↗

PubMed2000

Prevalence of heartworm infection in healthy cats in the lower peninsula of Michigan.

OBJECTIVE: To determine prevalence of heartworm infection among healthy, client-owned cats in the lower peninsula of Michigan. DESIGN: Cross-sectional prevalence study. ANIMALS: 1,348 healthy cats examined at private veterinary practices throughout the lower peninsula of Michigan. PROCEDURE: Sera were tested by use of an ELISA-based antigen test kit to determine infection and 2 commercially available antibody detection kits to determine exposure. A questionnaire was used to collect data to assess risk factors associated with infection. RESULTS: 25 cats had positive results for heartworm antigen, yielding an observed prevalence of 1.9%. Neither antibody test was reliable or provided reproducible results, and neither yielded positive results for more than 20% of the antigen-positive heartworm-infected cats. Multivariate regression indicated that cats from southeastern Michigan and cats > or = 2 years old had a higher risk of infection. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that most (80%) heartworm-infected cats in the lower peninsula of Michigan were from the southeastern part of the state, a pattern that closely paralleled the prevalence of heartworm infection in dogs. Therefore, knowledge of the regional prevalence of heartworm infection in dogs may be useful in assessing the risk of infection in cats. Results also suggested that currently available in-clinic heartworm antibody detection kits have limited utility in the diagnosis of heartworm infection in cats.

Animals↗

PubMed2000

Potentiation of mercury-induced nephrotoxicity by endotoxin in the Sprague-Dawley rat.

Endotoxin (lipopolysaccharide; LPS) and mercury are nephrotoxic compounds of food safety concern. Endotoxin is a product of cell walls of gram negative bacteria. Humans are constantly exposed to LPS through food, water and air. Food is the main source of mercury exposure for humans. Endotoxin potentiates the toxicity of a number of xenobiotics, but its interaction with nephrotoxic heavy metals has not been investigated. We tested the hypothesis that endotoxin enhances mercury-induced nephrotoxicity. Thirty-two, 41-43-day-old, male Sprague-Dawley rats were allocated randomly to four groups of eight rats each as follows: group I received 0.9% sodium chloride, group II received 2.0 mg of Escherichia coli 0128:B12 LPS kg(-1) once, group III received 0.5 mg mercuric chloride kg(-1) once, and group IV received 2.0 mg E. Coli 0128:B12 LPS kg(-1) once 4 h before receiving 0.5 mg mercury chloride kg(-1) once. Mercury, LPS and 0.9% sodium chloride were all injected IV through the tail vein. Rats were monitored for 48 h after mercury injection. Serum creatinine, urea nitrogen, and polyuria were significantly increased in rats given LPS plus mercury relative to those given either agent alone or saline (P</=0.05). The most severe morphologic lesions were found in rats given LPS plus mercury, which also had significantly greater renal mercury concentration than those given mercury alone (P < or = 0. 05). In conclusion, LPS potentiated mercury-induced nephrotoxicity.

Animals↗

PubMed2000

The effect of subclinical Mycobacterium paratuberculosis infection on days open in Michigan, USA, dairy cows.

A prospective cohort study design was used to evaluate the impact of subclinical Mycobacterium paratuberculosis infection on days open in a sample of Michigan dairy herds with a history of cows positive for M. paratuberculosis diagnosed by fecal culture. Participating herds were tested and productivity and reproduction records were monitored for 18 months. All cows > or = 24 months old were tested for M. paratuberculosis infection using the ELISA and radiometric fecal-culture (RFC) techniques. Test-negative cows were re-tested at the conclusion of the monitoring period. Multivariable regression models were used. Using both tests in parallel, the overall sample apparent prevalence for M. paratuberculosis infection was 41.8% (223/533 animals tested). Adjusting for diagnostic sensitivity and specificity, this resulted in a calculated sample true prevalence of 59.9%. ELISA-positive cows (on average) had a 28-day increase in days open when compared to ELISA-negative cows (p=0.02). The diagnostic method used to define a case altered the apparent association between paratuberculosis test status and days open. Fecal culture was a less-effective diagnostic tool for use in herds with a high prevalence of infected animals. The increase in days open in the ELISA-positive cows was an indication that perhaps reduced estrus expression or an increased post-partum anestrous period occurred in the subclinically infected ELISA-positive animals. This might have been due to a negative energy balance associated with M. paratuberculosis infection.

Animals↗

PubMed2000

Naturally occurring tuberculosis in white-tailed deer.

OBJECTIVE: To determine the distribution of lesions and extent of tissues infected with Mycobacterium bovis in a captive population of white-tailed deer. DESIGN: Cross-sectional study. ANIMALS: 116 captive white-tailed deer. PROCEDURE: Deer were euthanatized, and postmortem examinations were performed. Tissues with gross lesions suggestive of tuberculosis were collected for microscopic analysis and bacteriologic culture. Tissues from the head, thorax, and abdomen of deer with no gross lesions were pooled for bacteriologic culture. Tonsillar, nasal, oral, and rectal swab specimens, fecal samples, and samples of hay and pelleted feed, soil around feeding sites, and water from 2 natural ponds were collected for bacteriologic culture. RESULTS: Mycobacterium bovis was isolated from 14 of 116 (12%) deer; however, only 9 of 14 had lesions consistent with tuberculosis. Most commonly affected tissues included the medial retropharyngeal lymph node and lung. Five of 14 tuberculous deer had no gross lesions; however, M bovis was isolated from pooled tissue specimens from the heads of each of these deer. Bacteriologic culture of tonsillar swab specimens from 2 of the infected deer yielded M bovis. Mean (+/- SEM) age of tuberculous deer was 2.5 +/- 0.3 years (range, 0.5 to 6 years). Mycobacterium bovis was not isolated from feed, soil, water, or fecal samples. CONCLUSIONS AND CLINICAL RELEVANCE: Examination of hunter-killed white-tailed deer for tuberculosis commonly includes only the lymph nodes of the head. Results of such examinations may underestimate disease prevalence by as much as 57%. Such discrepancy should be considered when estimating disease prevalence.

Animals↗

PubMed2000

Influence of the Milk and Dairy Beef Quality Assurance Program on dairy farm drug management practices.

OBJECTIVE: To test the hypothesis that dairy farms certified in the Milk and Dairy Beef Quality Assurance Program (QAP) were more likely to use prudent drug management practices than farms that were not certified. DESIGN: Cross-sectional study. SAMPLE POPULATION: 141 Michigan dairy farms of which 74 were not certified in the QAP, 30 were involuntarily certified, and 37 were voluntarily certified. PROCEDURE: Dairy producers completed a self-administered questionnaire that focused on herd health management, drug use, record keeping, personnel management, and descriptive characteristics of their farm during 1993. Separate multivariable logistic regression models were developed to determine the association of QAP certification with each of the management practices. RESULTS: Results suggested that farms adopted specific management practices irrespective of certification. Many farms used visible identification and non-emergency veterinary services and discussed residue prevention with employees. Involuntary certification was associated with maintenance of good written treatment records and performance of on-farm drug residue testing. Voluntary certification was weakly associated with use of refrigerated drug storage. CONCLUSIONS AND CLINICAL RELEVANCE: QAP certification appeared to have been associated with the adoption of only a few prudent drug use practices, although QAP materials and framework were developed to assist veterinarians in the promotion of disease prevention, client communication, and residue prevention practices on farms. Veterinary care would benefit from the development and encouragement of better record keeping on farms.

Animals↗

PubMed2000

Parents' predicted transmitting abilities are not associated with culling prior to second lactation of Michigan, USA dairy cows.

The objective of this study was to test the association between parents' predicted transmitting abilities (PTAs) for milk, fat and protein and subsequent culling of heifers during rearing or first lactation. The data from 1992 to 1996 consisted of the culling outcome of 5619 Michigan Holstein heifers during rearing or first lactation, and the heifers' parents' PTAs from the period in which the heifers were born. Fixed-effect probit models (both dichotomous and ordered) estimated the relationships between culling and parents' PTAs. Herd effect was modeled as a fixed-effect. There was no association between PTAs of milk, fat, and protein for each heifer's parents and subsequent culling of the heifer during rearing or first lactation. Weak evidence for the necessity of modeling the herd effect as fixed was present. The lack of association between parents' PTAs and reason-specific culling (voluntary versus involuntary)--coupled with the counter-intuitive effects of parents' PTAs on the probability of being culled for each of the reasons--raised questions about the utility of classifying culling reasons according to the voluntary nature of the culling decision. We concluded that Michigan producers are not using parents' genetics in heifer-culling decisions.

Animal Husbandry↗

PubMed2000

Improvement of western blot test specificity for detecting equine serum antibodies to Sarcocystis neurona.

Equine protozoal myeloencephalitis (EPM) is a neurological disease of horses and ponies caused by the apicomplexan protozoan parasite Sarcocystis neurona. The purposes of this study were to develop the most stringent criteria possible for a positive test result, to estimate the sensitivity and specificity of the EPM Western blot antibody test, and to assess the ability of bovine antibodies to Sarcocystis cruzi to act as a blocking agent to minimize false-positive results in the western blot test for S. neurona. Sarcocystis neurona merozoites harvested from equine dermal cell culture were heat denatured, and the proteins were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis in a 12-20% linear gradient gel. Separated proteins were electrophoretically transferred to polyvinylidene fluoride membranes and blocked in 1% bovine serum albumin and 0.5% Tween-Tris-buffered saline. Serum samples from 6 horses with S. neurona infections (confirmed by culture from neural tissue) and 57 horses without infections (horses from the Eastern Hemisphere, where S. neurona does not exist) were tested by Western blot. Horses from both groups had reactivity to the 62-, 30-, 16-, 13-, 11-, 10.5-, and 10-kD bands. Testing was repeated with another step. Blots were treated with bovine S. cruzi antibodies prior to loading the equine samples. After this modification of the Western blot test, positive infection status was significantly associated with reactivity to the 30- and 16-kD bands (P<0.001, Fisher's exact test). The S. cruzi antibody-blocked Western blot had a sample sensitivity of 100% and sample specificity of 98%. It is concluded that the specificity of the Western blot test is improved by blocking proteins not specific to S. neurona and using reactivity to the 30- and 16-kD bands as the criterion for a positive test.

Animals↗

PubMed2000

Comparison of postmortem techniques for the detection of Mycobacterium bovis in white-tailed deer (Odocoileus virginianus).

A retrospective study of various diagnostic postmortem techniques used in a 4-year surveillance program for detection of Mycobacterium bovis infection in wild white-tailed deer (Odocoileus virginianus) was conducted. The tests evaluated were routine histopathology, acid-fast staining, detection of acid-fast bacilli in culture, and an M. tuberculosis group-specific genetic probe applied to pure cultures. Each of these techniques were compared with a reference or "gold standard" of mycobacterial culture and identification. Histopathology, the most rapid form of testing for M. bovis infection in white-tailed deer samples, had a sensitivity of 98% and a specificity of 87%, resulting in a positive predictive value of 94%. The detection of acid-fast bacilli by staining was less sensitive than histopathology (90%), but its higher specificity (97%) resulted in a positive predictive value of 99%. The detection of acid-fast bacilli on culture was both highly specific (93%) and sensitive (100%). The group-specific genetic probe had the highest sensitivity and specificity and produced results in complete agreement with those of mycobacterial culture, suggesting that this technique could be used as the new "gold standard" for this particular wildlife tuberculosis surveillance program.

Animals↗

PubMed2000

Use of pamidronate disodium to reduce cholecalciferol-induced toxicosis in dogs.

OBJECTIVE: To determine whether pamidronate disodium can reduce cholecalciferol-induced toxicosis in a dose-related manner. ANIMALS: 20 clinically normal, 8- to 12-month-old male Beagles. PROCEDURE: All dogs were given 8 mg of cholecalciferol (CCF)/kg of body weight once orally, then were randomly assigned to 4 groups of 5 dogs each. Dogs were treated with IV administration of 0.9% NaCl solution (SC group), 0.65 mg of pamidronate/kg in 0.9% NaCl solution (LP group), 1.3 mg of pamidronate/kg in 0.9% NaCl solution (MP group), or 2.0 mg of pamidronate/kg in 0.9% NaCl solution (HP group) on days 1 and 4 after administration of CCF. Dogs were observed for 14 days, and serial blood samples were collected for serum biochemical, electrolyte, and 25-hydroxyvitamin D3 analyses. Urine samples were collected for determination of specific gravity. Glomerular filtration rate (GFR) was determined by plasma iohexol clearance. Histologic examination of renal tissue was performed. RESULTS: One dog in the SC group was euthanatized 3 days after administration of CCF because of severe clinical signs of toxicosis. Dogs in the HP group had significantly higher mean GFR (day 3), serum potassium concentrations (day 14), and urine specific gravity (days 7 and 14) and significantly lower mean serum creatinine concentrations and total calcium X phosphorus concentration product (days 4 and 7) than dogs in the SC group. Dogs in the HP group had no abnormal findings on histologic examination of renal tissue, dogs in the LP and MP groups had trace to mild mineralization of renal tissue, and dogs in the SC group had moderate mineralization and cellular necrosis of proximal renal tubules. CONCLUSIONS AND CLINICAL RELEVANCE: Pamidronate disodium is a potentially useful drug to reduce CCF-induced toxicosis and other causes of hypercalcemia associated with increased bone resorption in dogs.

Animals↗

PubMed1999

Spatial and temporal distribution of selected canine cancers in Michigan, USA, 1964-1994.

Although rates are commonly used to compare regional disease occurrence, rate-independent methods might also be useful in circumstances where geographic occurrence of a disease is known, but calculation of disease rates is not feasible. This is frequently the case for diseases in companion animals, where accurate enumeration of populations-at-risk is often arduous. This study had two objectives: to demonstrate a rate-independent method for investigating disease aggregation in companion animals; and, to assess the spatial and temporal clustering of canine cases of four cancers that are biologically similar in dogs and humans. Geographic information systems and point-pattern analysis were used to assess the spatial and temporal clustering of incident cases of four types of canine cancer in three counties in Michigan between 1964 and 1994, and to generate hypotheses concerning disease aggregation. Significant (P < or = 0.01) spatial clustering was found that varied by county and cancer type. No definitive temporal patterns could be deduced from a temporal analysis of the cases of canine cancer in this study. These results demonstrate distance-based methods for assessing clustering of disease, and suggest that processes determining the aggregation of canine cancer cases do not act in a spatially uniform manner.

Animals↗

PubMed1999

Factors influencing recovery from and duration of lameness in Michigan (USA) horses.

The objective of this study was to identify factors that may affect recovery from and duration of a case of lameness in a stratified random sample of Michigan horses. This was done using data from Phase-II of the Michigan equine monitoring system (MEMS Phase-II), the equine health-monitoring study [Kaneene et al., Prev. Vet. Med. 29 (1997b) 277-292; Ross and Kaneene, Prev. Vet. Med. 28 (1996a) 209-224; Ross and Kaneene, Prev. Vet. Med. 29 (1996b) 59-75; Ross et al., Am. J. Vet. Res. 59 (1997) 23-29]. In this study, statistical modelling was conducted to evaluate risk factors affecting recovery from and duration of lameness using multivariable logistic regression and Cox's proportional hazards regression, respectively. Of 357 incident lameness cases reported during MEMS Phase-II, 280 (78.6%) were reported to have recovered. The median duration of a lameness case was 18 days (1st quartile (Q): 1, maximum (Max): 360). A total of 296 of 357 (82.9%) incident lameness cases received some type of treatment. Of 619 total treatments used, 329 (53.2%) were administered, conducted or applied by a veterinarian. Horses experiencing other types of lameness were less likely to recover than those experiencing hoof lameness (odds ratio (OR) = 0.48; 95% CI: 0.25, 0.93). Horses that had participated in exercise-related activities during the study period and prior to the lameness were more likely to recover (OR = 1.91; 95% CI: 1.05, 3.50). Treatment of the lameness was associated with an increased likelihood of recovery (OR = 1.82; 95% CI: 0.97, 3.45). Cases with a veterinarian involved in the diagnosis were associated with a decreased risk of recovery (OR = 0.48; 95% CI: 0.27, 0.84) and a longer duration lameness (HR = 0.58; 95% CI: 0.45, 0.73)--which might indicate that these cases were more complex or severe. Although cases treated for lameness were more likely to recover (OR = 1.82; 95% CI: 1.05, 3.50), treatment was not associated with lameness duration (HR = 0.58; 95% CI: 0.45, 0.73).

Animals↗

PubMed1999

Herd-level economic analysis of the impact of paratuberculosis on dairy herds.

OBJECTIVE: To perform a herd-level analysis of economic losses associated with paratuberculosis in dairy herds. DESIGN: Cross-sectional study. SAMPLE POPULATION: A multistage stratified random sample of 121 dairy herds in Michigan. PROCEDURE: A 2-part questionnaire was used to gather data on management practices, herd productivity, labor use, and expenditures. Blood samples were collected from a random sample of cows > or = 2 years old in each herd and tested for antibodies to Mycobacterium paratuberculosis. A herd was considered negative for paratuberculosis if results for all cows tested were negative. Multivariable linear regression was used to evaluate the data. RESULTS: A 10% increase in proportion of cows positive for paratuberculosis was associated with a 33.4 kg (73.5 lb) decrease in mean weight of culled cows. Mortality rate among herds positive for paratuberculosis was 3% higher than rate among herds negative for paratuberculosis. Herds positive for paratuberculosis did not have a significantly higher annual number of hours of labor per cow than did herds negative for paratuberculosis. CLINICAL IMPLICATIONS: For a herd of average size and cull rate, the reduction in mean weight of culled cows attributable to paratuberculosis represented a loss of approximately $1,150 annually for each 10% increase in herd prevalence of paratuberculosis. The increased mortality rate attributable to paratuberculosis represented a loss of between $1,607 and $4,400 on the basis of lost slaughter value and cost of replacement heifers.

Animals↗