Udder cleft dermatitis and sarcoptic mange in a dairy herd

OBJECTIVE: To determine prevalence of udder cleft dermatitis in a dairy herd that was experiencing an outbreak of sarcoptic mange. DESIGN: Clinical survey. ANIMALS: 1,597 Holstein cows and late-gestation heifers. PROCEDURE: Animals were examined for udder cleft dermatitis and for skin lesions consistent with sarcoptic or chorioptic mange. Skin scrapings were collected from 56 cows and examined for ectoparasites. The herd was revisited 1 year later, and prevalences of udder cleft dermatitis and lesions consistent with mange were determined in 506 cows. RESULTS: Of the 1,597 cattle examined, 280 (18%) had udder cleft dermatitis, and 1,397 (87.5%) had lesions consistent with mange. In 43 of 56 (77%) cows, skin scrapings revealed Sarcoptes mites. Udder cleft dermatitis was significantly more common in older than in younger cows. In first-lactation cows, udder cleft dermatitis was less common during the first 4 months of lactation than in the later stages of lactation, but udder cleft dermatitis was identified in cows in all stages of lactation and in cows that were not lactating. The herd was treated with eprinomectin to control mites, and prevalence of lesions consistent with mange 1 year later was only 2.8%. However, prevalence of udder cleft dermatitis was still 12%. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that cows in any stage of lactation and cows that are not lactating can have udder cleft dermatitis but that lesions are more common in older cows. Control of sarcoptic mange was accompanied by a moderate reduction in the prevalence of udder cleft dermatitis but did not eliminate the condition.     

Vertical position of the patella in the stifle joint of clinically normal large-breed dogs

OBJECTIVE: To define the vertical position of the patella in clinically normal large-breed dogs. SAMPLE POPULATION: Cadavers of 13 clinically normal large-breed dog. PROCEDURE: Both hind limbs were harvested with intact stifle joints and mounted on a positioning device that allowed full range of motion of the stifle joint. Lateral radiographic views were obtained with the stifle joints positioned at each of 5 angles (148 degrees, 130 degrees, 113 degrees, 96 degrees, and 75 degrees). Vertical position of the patella through a range of motion was depicted on a graph of mean stifle angle versus corresponding mean proximal patellar position (PPP) and distal patellar position (DPP) relative to the femoral trochlea for each dog. Ratio of length of the patellar ligament to length of the patella (L:P) was determined for each dog. Overall mean, SD, and 95% confidence intervals for L:P were calculated for all dogs. RESULTS: Evaluation of vertical position of the patella through a range of motion revealed a nearly linear relationship between joint angle and PPP and joint angle and DPPF Evaluation of L:P results did not reveal significant differences between limbs (left or right) or among joint angles. Overall mean +/- SD L:P for all dogs was 1.68 +/- 0.18 (95% confidence interval, 1.33 to 2.03). CONCLUSIONS AND CLINICAL RELEVANCE: The L:P proved to be a repeatable measurement of vertical patellar position, which is independent of stifle angles from 75 degrees to 148 degrees.This measurement could be used as a quantitative method for diagnosing patella alta and patella baja in large-breed dogs.     

Population-based study of fecal shedding of Clostridium perfringens in broodmares and foals

OBJECTIVE: To determine the percentage of broodmares and foals that shed Clostridium perfringens in their feces and classify the genotypes of those isolates. DESIGN: Prospective cross-sectional study. ANIMALS: 128 broodmares and their foals on 6 equine premises. PROCEDURES: Anaerobic and aerobic bacteriologic cultures were performed on feces collected 3 times from broodmares and foals. All isolates of C. perfringens were genotyped. RESULTS: Clostridium perfringens was isolated from the feces of 90% of 3-day-old foals and 64% of foals at 8 to 12 hours of age. A lower percentage of broodmares and 1- to 2-month-old foals shed C. perfringens in their feces, compared with neonatal foals. Among samples with positive results, C. perfringens type A was the most common genotype identified (85%); C. perfringens type A with the beta2 toxin gene was identified in 12% of samples, C. perfringens type A with the enterotoxin gene was identified in 2.1% of samples, and C. perfringens type C was identified in < 1% of samples. CONCLUSIONS AND CLINICAL RELEVANCE: Clostridium perfringens was identified from the feces of all but 6 foals by 3 days of age and is likely part of the normal microflora of neonatal foals. Most isolates from broodmares and foals are C. perfringens type A; thus, the clinical relevance of culture results alone is questionable. Clostridium perfringens type C, which has been associated with neonatal enterocolitis, is rarely found in the feces of horses.     

The effect of a porcine-derived small intestinal submucosa product on wounds with exposed bone in dogs

OBJECTIVE: To determine the effect of a porcine-derived small intestinal submucosa product (PSIS) on healing time, epithelialization, angiogenesis, contraction, and inflammation of wounds with exposed bone on the distal aspect of the limbs of dogs. STUDY DESIGN: Prospective, controlled, experimental study. ANIMAL POPULATION: 10 young adult, purpose-bred, male Beagles. METHODS: Small wounds with exposed bone were created on the lateral aspect of metatarsal V and the medial aspect of metatarsal II on both hindlimbs. Three sheets of PSIS were sutured into the wounds of the treated limb, and the other limb served as a control. On day 10, punch biopsies of the medial metatarsal wounds were collected and were evaluated microscopically after routine hematoxylin and eosin and phosphotungstic acid hematoxylin (PTAH) staining. The lateral metatarsal wounds were evaluated by planimetry and laser Doppler perfusion imaging on days 7, 14, and 21. Time until complete wound healing was also recorded. The level of significance was set at P < or =.05 for all statistical analyses. RESULTS: Laser Doppler perfusion measurements were significantly higher in control wounds on day 7, but no differences were noted on days 14 and 21. No significant differences in planimetric values, histopathologic appearance, or time until complete wound healing were noted among treated and control groups. CONCLUSIONS: No objective differences in healing were noted between control wounds and wounds treated with PSIS. CLINICAL RELEVANCE: There appears to be no contraindication to the use of PSIS on clean wounds with exposed bone on the distal limbs of dogs. However, our objective data provides no evidence that this product affects epithelialization, contraction, or time to complete healing in wounds with exposed bone.     

Genetic and management factors that influence the susceptibility of cattle to Mycobacterium bovis infection

Genetic variation in the susceptibility of cattle to Mycobacterium bovis infection exists in differences between families and species, but not breeds. Susceptibility to M. bovis infection increases with age of cattle. Natural exposure to M. bovis or environmental mycobacteria may assist in the development of specific immunity, but there is no direct evidence for such immunological priming of tuberculosis resistance in cattle. This has, however, been demonstrated in humans and other animals. Since non-specific mechanisms have a role in protective immunity, developing an effective vaccine will be difficult, even though some protection of other species has been achieved. Immunological suppression in the periparturient period can produce anergic reactors, which may act as a constant source of infection for cattle-to-cattle transmission. Circumstantial evidence suggests that an adequate intake of mineral, vitamin and protein reduces the susceptibility of cattle. Although weather patterns have been implicated in the susceptibility of herds to M. bovis infection, there is insufficient information to determine the risk factors precisely. It is concluded that some reduction in the susceptibility of cattle to M. bovis infection can be achieved by modifications to the management system to minimize risk factors, but that a considerable amount of further research is required.     

In vitro analysis of antiangiogenic activity of fungi isolated from clinical cases of equine keratomycosis

OBJECTIVE: The goal of this project was to explore the possibility that fungal organisms produce metabolites that inhibit angiogenesis. Procedures Fungal cultures were obtained from cases of keratomycosis, grown in Sabouraud's dextrose broth, and sterile filtered for use in experiments. The Matrigel assay was used to screen the filtrate samples for antiangiogenic activity. Matrigel is a basement membrane matrix that supports the differentiation of human umbilical vein endothelial (HUVE) cells into a capillary-like network of tubules. HUVE cells were cultured using standard techniques and passaged at confluence, with all cells being used at passage 3-6. HUVE cells (40 000 cells) were pipetted into each well of a 24-well tissue-culture plate coated with Matrigel. An aliquot of fungal media filtrate was added to each well and the plates allowed to incubate for 18 h, at which time they were evaluated for tubule formation. RESULTS: Two fungal isolates showed inhibition of tubule formation. The addition of 100, 200 and 400 &mgr;L of the fungal media filtrate from the first isolate (Fusarium sp. 99A34574) produced a consistent and dose-dependent inhibition of tubule formation. The second isolate (Aspergillus sp. 271599) did not show inhibition of tubule formation with 100 or 200 &mgr;L added to the wells, however, it did show inhibition at 400 &mgr;L/well. The remaining three isolates did not cause inhibition at any concentration. CONCLUSIONS: Our findings suggest that certain fungal organisms produce metabolites that inhibit tubule formation in vitro, and that these metabolites may play a significant role in altering the host vascular response to fungal infections of the cornea.     

Development of an assay to determine single nucleotide polymorphisms in the prion gene for the genetic diagnosis of relative susceptibility to classical scrapie in sheep.

The objective of this study was to develop a reliable Taqman 5' Nuclease Assay for genotyping sheep for scrapie susceptibility. The sheep prion gene contains 2 single nucleotide polymorphisms (SNPs) that may mediate resistance to classical scrapie, one at codon 136, alanine (A) or valine (V), and another at codon 171, arginine (R) or glutamine (Q). The R allele appears to confer resistance to classical scrapie, with the AA(136) RR(171) genotype the most resistant to scrapie and QR(171) only rarely infected in the US sheep population. The Assays by Design protocol was used for development of probes and primers for codon 136 and Primer Express for codon 171. Commercially available kits were used to isolate genomic DNA from blood or muscle. For validation, 70 SNP determinations for each codon were compared to commercial testing with an error rate of less than 1%. Then, 935 samples from blood (n = 818) and muscle (n = 117) were tested for both codons with 928 successful determinations and only 7 samples (<1% of total samples) that needed repeating. Genotypes were AA QQ (n = 102; 11.0%), AV QQ (n = 28; 3.0%), AA QR (n = 396; 42.7%), AV QR (n = 54; 5.8%), and AA RR (n = 348; 37.5%). Thus, 86% of the sheep tested (n = 798) contained R at codon 171 and were expected to be scrapie-resistant. This new Taqman 5' Nuclease SNP genotyping assay is accurate, easy to perform, and useful in the study of classical scrapie in sheep and its prevention through selective breeding programs to eliminate highly susceptible animals.     

The effects of cooling and vitrification of embryos from mares treated with equine follicle-stimulating hormone on pregnancy rates after nonsurgical transfer

Equine embryos can remain viable for 12 to 24 hours when cooled and stored at 5°C.¹ Cryopreservation of embryos would allow for long-term preservation of genetic material and more efficient management of embryo recipients. This study compared pregnancy rates after transfer of equine embryos vitrified within 1 hour of collection or cooled for 12 to 19 hours before vitrification. Mares (N = 40) were superovulated using equine follicle-stimulating hormone (eFSH). Embryos were recovered 6.5 days after ovulation or 8 days after human chorionic gonadotropin. Forty morulae or early blastocysts with a grade of 1 to 2 and <300 mm in diameter were randomly assigned to 1 of 2 treatments: Group 1 (n = 20), washed 4 times in a commercial holding medium and then vitrified; Group 2 (n = 20), washed 3 times and then stored in the same holding medium at 5°C to 8°C in a passive cooling device for 12 to 19 hours before being vitrified. To thaw, embryos were warmed by holding the straw in air at room temperature for 10 seconds and then submerged in a water bath (20°C to 22°C) for an additional 10 seconds. The contents of the straw were transferred directly into a recipient that had ovulated 4 to 6 days previously. There were no differences (P > .05) in embryo diameter, grade, or morphology score between treatment groups before vitrification. Pregnancy rates (day 16) were not different (P > .05) between embryos vitrified immediately after collection (15 of 20; 75%) and embryos cooled for 12 to 19 hours before vitrification (13 of 20; 65%). Based on these results, small equine embryos (<300 mm) can be stored at 5°C to 8°C for 12 to 19 hours before vitrification without a significant loss of viability.