Progressive alopecia associated with hypoparathyroidism in a Jersey heifer.

BACKGROUND: Chronic progressive generalized alopecia in dairy cattle has been anecdotally discussed in veterinary forums. OBJECTIVE: To describe subclinical changes in an otherwise apparently healthy animal with chronic progressive generalized alopecia. ANIMALS: One 10-month-old Jersey heifer. METHODS: Case report. RESULTS: A heifer was presented for chronic progressive alopecia. The skin was hyperpigmented and very thin (2.4 ± 0.0 mm, compared with 8.1 ± 0.3 mm measured in four contemporaneous Jersey heifers). Histopathological examination of the skin revealed severe epidermal hyperplasia, orthokeratotic hyperkeratosis and diffuse follicular atrophy. Clinicopathological changes included hypocalcaemia that did not respond to calcium therapy. Serum parathyroid hormone (PTH) was not detected, compared with 1.38 ± 0.78 pmol/L in four contemporaneous Jersey heifers. A diagnosis of hypoparathyroidism was made based on hypocalcaemia and low PTH in the presence of normal magnesium levels. The heifer was otherwise healthy and was allowed to continue normal life. A spontaneous abortion occurred at 5.5 months of pregnancy and this was likely due to the presence of twin fetuses. Despite targeted therapy of the ensuing retained placenta, the heifer declined in health and had to be euthanized. From the time of diagnosis with hypoparathyroidism until euthanasia (29 months of age), blood levels of calcium, phosphorus and PTH were regularly monitored. Calcium and phosphorus levels varied widely. Serum PTH was consistently undetectable. At postmortem examination, the parathyroid glands could not be located. CONCLUSIONS AND CLINICAL IMPORTANCE: To our knowledge, this is the first report of naturally occurring hypoparathyroidism in cattle and with a clinical presentation of alopecia.

Control of extensive chorioptic mange natural infection in lactating dairy cattle without milk withdrawal.

Dairy cattle are becoming increasingly complicated to treat in the USA due to the great limitation of approved drugs. Additionally, most drugs require withdrawal times for milk that are not viable for treating entire dairy herds. The objective of this field trial was to determine the efficacy of eprinomectin, one of only two parasiticides approved for lactating dairy cattle, for eradication of naturally occurring chorioptic mange on a commercial dairy farm. All animals present on the farm were treated on the same day and, later, new animals introduced to the premises were treated on arrival. All cows were re-treated at dry-off. Lesion scoring was performed five times over a period of 12 months. A reduction in the proportion of cows with lesions was apparent 3 months after treatment and, although the proportion stayed low, it increased again at 12 months post-treatment. Logistic regression to evaluate factors associated with the presence of mange lesions showed that older cows, late lactation, and recent treatment, were associated with presence of lesions. It also showed that multiple treatments (whole-herd treatment and at dry-off) helped to reduce the presence of lesions. No increase in milk production could be measured, but animal wellbeing improved. The results of this study show that chorioptic mange can be controlled in entire herds, although multiple treatments will be required to potentially eradicate the parasite. The value of the study is that it shows that mange can be controlled in dairy cattle with approved drugs, eliminating the need to use non-approved agents.

Rare Cryptococus gattii infection in an immunocompetent dairy goat following a cesarean section.

A 5-year-old dairy goat was presented seven weeks post cesarean section for incomplete healing of the incision site. Cytology revealed cryptococcal organisms that were confirmed by the Centers for Disease Control as Cryptococcus gattii type VGIIa. Most cryptococcomas were surgically removed, but some penetrated deep in to the muscular layers and likely into peritoneum. The goat was treated daily with oral fluconazole for 6 months, and had a normal life for almost 2 years.

Putative Malassezia dermatitis in six goats.

Histopathology submissions from 28 goats with dermatological disease were identified in an archival search of pathology files. Microscopic sections of skin biopsy specimens were examined for the presence of Malassezia spp. organisms. Six cases with many Malassezia yeasts were identified histopathologically. Based on the extent of clinical disease, three cases were regarded as localized and three were generalized infections. Clinical findings included alopecia with dry seborrhoea (four cases), greasy seborrhoea (one case), and no clinical findings specific to localized Malassezia infection when concurrent bacterial infection was present (one case). Mild pruritus was reported in two cases of generalized infection. No breed predilection was apparent. Three cases were male and three were female. Malassezia dermatitis occurred in goats from 10 months to 13 years of age. Three of six cases had concurrent bacterial infection. Skin lesions resolved following topical antifungal therapy in the two goats that were treated. Histopathological findings in all cases were severe follicular and epidermal orthokeratotic hyperkeratosis with minimal epithelial change and mild superficial perivascular to interstitial nonsuppurative inflammation. Numerous budding yeasts were visible within the stratum corneum of all cases; however, Malassezia was not isolated in the three cases in which culture was attempted. Based upon these findings, the authors suggest that the diagnosis Malassezia dermatitis in goats is most likely to be made by cytological examination of skin impressions or by examination of skin biopsy samples.

Effect of systematic parturition induction of long gestation Holstein dairy cows on calf survival, cow health, production, and reproduction on a commercial farm.

The objective of this study was to evaluate the effect of parturition induction on dairy cattle with long gestation (past due-date) single pregnancies on calf survivability, cow health, production, and reproduction. There was an induction period during which all cows and heifers reaching 282 days of gestation were induced with dexamethasone (n = 614). Control cows calved the year after, had a gestation length > 282 d and were not induced (n = 508). As the induced and non-induced groups were not contemporaneous, data were standardized using the ratio between the herd baselines for each period. Multivariate analyses of the data showed that induced cows were 1.41 times more likely (P = 0.020) to become pregnant in the lactation following the studied calving than non-induced cows with long gestation. There was no difference in the risk of difficult calvings, stillbirths, culling due to reproductive reasons, average milk production, average days open or risk of abortion in the following lactation between induced and non-induced cows. There seemed to be a relationship between parturition induction and a lower risk of post-partum death, although this was not statistically significant (P = 0.162), because including induction as a factor in the model markedly improved the fit of the data. There was no information on incidence of retained placenta (RP) for the non-induced group. In conclusion, parturition induction resulted in more cows becoming pregnant and a seemingly lower risk of post-spartum death without affecting calving difficulty, calf viability, or milk production.

A survey of reasons why veterinarians enter rural veterinary practice in the United States.

OBJECTIVE: To identify factors associated with interest in or choosing a career in rural veterinary practice (RVP). DESIGN: Cross-sectional descriptive study. SAMPLE POPULATION: Veterinarians and veterinary students in the United States. PROCEDURES: Veterinary students and veterinarians in any area of practice were solicited to participate in an online survey through invitation letters sent to various veterinary associations. Proportions of respondents assigning high importance to various factors were analyzed for differences among gender, age, and background groups. RESULTS: 1,216 responses were received. In general, survey respondents indicated that RVP could be characterized as the practice of veterinary medicine in any community where agriculture represented a significant part of the local economy. Responses also indicated that RVP should not be confused with large animal or food animal exclusive practice. Most respondents (38.9%) developed an interest in RVP early in life (before 8th grade), with 13.0% reportedly developing their interest in RVP during veterinary school. The most highly ranked factors with regard to influence on developing an interest in RVP were having relatives with a farm background, having a veterinarian in RVP as a mentor, and exposure to RVP during veterinary school. Gender, generational category, background (rural vs urban), and livestock experience were significantly associated with when respondents developed an interest in RVP and with factors important in developing that interest. CONCLUSIONS AND CLINICAL RELEVANCE: Results of the present study suggested that various factors are associated with interest in and choosing a career in RVP. These factors should be considered when strategies for increasing interest and encouraging careers in RVP are planned.

A survey of reasons why veterinarians leave rural veterinary practice in the United States.

OBJECTIVE: To identify factors associated with veterinarians leaving a career in rural veterinary practice (RVP). DESIGN: Cross-sectional descriptive study. SAMPLE POPULATION: Veterinarians from the United States who no longer worked in RVP. PROCEDURES: Veterinarians in any area of practice were solicited to participate in an online survey through invitation letters sent to various veterinary associations. Those who indicated that they had left RVP were asked to rank the importance of various potential factors in their decision to leave RVP. RESULTS: 805 responses were obtained from veterinarians who had worked in RVP, of which 246 (30.6%) had left RVP. Most (231/246 [93.9%]) of those who reported leaving RVP had been in practice > 5 years, and 75.2% (185/246) had been in practice > 12 years. Eighty-three (33.7%) who left RVP pursued careers in urban areas, 72 (29.3%) entered academia, and 7 (2.8%) retired. Reasons for leaving RVP ranked by the highest proportions of respondents as being of high importance were emergency duty, time off, salary, practice atmosphere, and family concerns. Women ranked factors such as time off, mentorship, practice atmosphere, conflict with staff, and gender issues as being of high importance more often than men did. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that the perceived shortage of veterinarians in RVP may be in part influenced by a lack of retention, particularly among experienced veterinarians. Targeted efforts to tackle issues related to emergency duty, time off, salary, practice atmosphere, and family issues could help alleviate the efflux from RVP.

Comparison between manual and automated total nucleated cell counts using the ADVIA 120 for pleural and peritoneal fluid samples from dogs, cats, horses, and alpacas.

BACKGROUND: Analysis of body fluids includes an estimate of total nucleated cell count (TNCC). Automated methods may enhance the accuracy and timeliness of TNCC results. OBJECTIVE: The purpose of this report was to assess the ability of the ADVIA 120 hematology analyzer to accurately count nucleated cells in pleural and peritoneal fluids from animals, compared with manual counts. METHODS: Pleural and peritoneal fluids submitted in EDTA tubes to our laboratory over a 17-month period were used in the study. TNCC/microL was determined by a manual method, using a hemocytometer, and by an automated method, using the ADVIA 120. Correlation of results was determined by Passing-Bablok regression, Bland-Altman plots, and Pearson correlation analysis. RESULTS: Samples from dogs (n=36), cats (n=36), horses (n=59), and alpacas (n=11) were analyzed. High correlation in TNCC between methods was found for peritoneal fluid (n=93, r=.959), pleural fluid (n=49, r=.966), and all fluids combined (n=142, r=.960) (P<.001). Variation between methods was greater in samples with TNCCs<1000/microL (r=.62, P<.001). The ADVIA systematically overestimated the number of cells in all fluid samples by 95 cells/microL (confidence interval=19.2-190.5/muL). CONCLUSION: The ADVIA 120 reliably determines TNCC in pleural and peritoneal effusions and can be recommended for routine veterinary laboratory analysis.

Frequency of appropriate and inappropriate presentation and analysis methods of ordered categorical data in the veterinary dermatology literature from January 2003 to June 2006.

Clinical outcomes that are difficult to measure directly are often graded with ordinal scales in the veterinary dermatology literature to approximate objective evaluation. Ordered categorical scales require statistical presentation and analysis methods consistent with the structure of the data. The objective of this study was to determine the frequency of inappropriate presentation and analysis methods of ordered categorical data in the recent veterinary dermatology literature. A total of 62 articles published between 1 January 2003 and 30 June 2006 in 16 journals reported categorical scales and were included in the study. The presentation and analysis methods of ordered categorical data were classified as appropriate or inappropriate based on published recommendations. Forty articles (64.5%) utilized a median of four ordinal scales (range 1-13). Inappropriate presentation methods of ordered categorical data were identified in 23 of 40 articles (57.5%). These included reporting inappropriate summary statistics (n = 17) and summation of ad hoc numerical rating scales (n = 15). Inappropriate analytical methods were used in nine of 40 articles (22.5%). These included inappropriate use of t-tests (n = 3) and analysis of variance (anova, n = 6). The frequency of inappropriate presentation and analysis methods of ordered categorical data in the veterinary dermatology literature is similar to that reported for several fields in the human medical literature. In order to reduce the likelihood of making unwarranted implications or conclusions regarding ordinal data, authors should follow established guidelines for methods of presentation and analysis of ordered categorical scales.

Use of a simulation model to evaluate sampling strategies for characterization of antimicrobial resistance in non-type-specific Escherichia coli isolated from dairy cows.

OBJECTIVE: To evaluate various sampling strategies for potential use in measuring prevalence of antimicrobial susceptibility in cattle. SAMPLE POPULATION: 500 isolates of non-type-specific Escherichia coli (NTSEC) isolated from the feces of 50 cows from 2 dairy farms (25 cows/farm and 10 isolates/cow). PROCEDURES: Diameters of inhibition zones for 12 antimicrobials were analyzed to estimate variation among isolates, cows, and farms and then used to determine sampling distributions for a stochastic simulation model to evaluate 4 sampling strategies. These theoretic sampling strategies used a total of 100 isolates in 4 allocations (1 isolate from 100 cows, 2 isolates from 50 cows, 3 isolates from 33 cows, or 4 isolates from 25 cows). RESULTS: Analysis of variance composition revealed that 74.2% of variation was attributable to isolates, 18.5% to cows, and 7.3% to farms. Analysis of results of simulations suggested that when most of the variance was attributable to differences among isolates within a cow, culturing 1 isolate from each of 100 cows underestimated overall prevalence, compared with results for culturing more isolates per cow from fewer cows. When variance was not primarily attributable to differences among isolates, all 4 sampling strategies yielded similar results. CONCLUSIONS AND CLINICAL RELEVANCE: It is not always possible to predict the hierarchical level at which clustering will have its greatest impact on observed susceptibility distributions. Results suggested that sampling strategies that use testing of 3 or 4 isolates/cow from a representative sample of all animals better characterize herd prevalence of antimicrobial resistance when impacted by clustering.

Outcome of tactile conditioning of neonates, or "imprint training" on selected handling measures in foals.

Behavioural reactions to selected handling procedures were compared between conditioned, or imprint-trained, and untrained foals raised on the same farm. Nineteen randomly chosen healthy foals were imprint trained at birth and 24 h later (Group A). Twenty-one similar foals that were not imprint-trained served as age-matched controls (Group B). Training began within 10 min of birth and consisted of touch desensitization by gentle rubbing. Each tactile stimulus was repeated 30-50 times over 45-60 min, until the foal no longer resisted the procedure and appeared relaxed. The procedure was then repeated at 24 h of age. At that time a physical examination and blood analysis were performed to assess the foals' health status. Group B animals were not handled except for a brief physical examination and blood analysis at 24 h of age. Thereafter all foals were kept on pastures with their dams with no further handling until they were three months of age. Any foals handled for other reasons before that time were excluded from the study. At three months, each of the 28 foals that completed the study experienced the following handling procedures: acceptance of restraint, haltering, complete physical examination, acceptance of a plastic rebreathing bag, touching the whole body, intramuscular vaccination in the neck, intranasal vaccination, and deworming with oral paste. Response to each procedure was scored (1=not resistant, 2=low resistance, 3=strong resistance, 4=not possible without major physical restraint). Conditioned foals (Group A) were significantly less resistant to touching the front and hind legs and picking up the hind feet (P < 0.05). The administration of vaccines and paste dewormer and the collection of blood were tolerated by the majority of the foals of both groups with no or low resistance. It appeared that neonatal imprint training resulted in a learned behaviour that resulted in decreased self-defence responses towards handling the limbs at three months of age.

Development of a simulation model to evaluate the effect of vaccination against Tritrichomonas foetus on reproductive efficiency in beef herds.

OBJECTIVE: To develop a model to evaluate the effect of vaccination against Tritrichomonas foetus on reproductive efficiency in beef herds. SAMPLE POPULATION: A beef herd of 300 cows and 12 bulls (8 bulls < or = 3 years old and 4 bulls > 3 years old). PROCEDURE: The model was developed by use of data for various risk factors and vaccine efficacy. The reference herd was considered to be one in which T. foetus had been diagnosed and bulls were tested for T. foetus before the breeding season. Five thousand iterations were run for each of 13 simulations, with each simulation representing a separate combination of risk factors. RESULTS: In all simulations, vaccination resulted in significantly higher calving incidence than nonvaccination. Shared grazing was found to be the most significant risk factor for a decrease in calving incidence attributable to T. foetus infection, followed in importance by lack of testing before the breeding season and a higher proportion of old bulls. Combinations of risk factors contributed to a loss of income of up to 22%, some of which could be blunted by vaccination. CONCLUSIONS AND CLINICAL RELEVANCE: Highest calving incidence is achieved when all bulls are tested for T. foetus before the breeding season and all bulls with positive culture results are culled. Avoiding all risk factors is better than vaccinating, but when this is not feasible for a given herd, the results of this simulation indicate that proper vaccination can decrease economic losses attributable to abortions caused by T. foetus.

Effect of post-insemination supplementation with PRID on pregnancy in repeat-breeder Holstein cows.

Embryonic mortality contributes to repeat-breeding in dairy cows; luteal insufficiency is a known cause of embryonic mortality. The objective of this study was to assess the efficacy of supplementation with exogenous progesterone for 14 days on pregnancy maintenance in inseminated repeat-breeder dairy cows. On Day 5 after insemination, treated cows ( n=143 ) received a modified PRID (i.e. without estradiol capsule), which was removed on Day 19. Control cows ( n=148 ) did not receive any treatment. Overall there was no effect of PRID supplementation on pregnancy rates. However, when the study population was stratified by parity and stage of lactation, PRID supplementation significantly improved pregnancy rate in first and second parity late lactation cows (risk ratio = 3.26; 95% CI 1.22, 8.69). Pregnancy rates did not differ between PRID-treated cows with ( n=81 ) and without vaginitis. Control cows tended ( P=0.077 ) to have a higher proportion of abortions than PRID-treated cows (7/50 versus 2/51, respectively). In conclusion, young late lactation repeat-breeder cows benefited from progesterone supplementation, in terms of maintaining pregnancy until traditional time of pregnancy diagnosis.