Jeff W. Tyler

Comparison of four methods to assess colostral IgG concentration in dairy cows

OBJECTIVE To determine sensitivity and specificity of 4 methods to assess colostral IgG concentration in dairy cows and determine the optimal cutpoint for each method. DESIGN Cross-sectional study. ANIMALS 160 Holstein dairy cows. PROCEDURES 171 composite colostrum samples collected within 2 hours after parturition were used in the study. Test methods used to estimate colostral IgG concentration consisted of weight of the first milking, 2 hydrometers, and an electronic refractometer. Results of the test methods were compared with colostral IgG concentration determined by means of radial immunodiffusion. For each method, sensitivity and specificity for detecting colostral IgG concentration < 50 g/L were calculated across a range of potential cutpoints, and the optimal cutpoint for each test was selected to maximize sensitivity and specificity. RESULTS At the optimal cutpoint for each method, sensitivity for weight of the first milking (0.42) was significantly lower than sensitivity for each of the other 3 methods (hydrometer 1, 0.75; hydrometer 2, 0.76; refractometer, 0.75), but no significant differences were identified among the other 3 methods with regard to sensitivity. Specificities at the optimal cutpoint were similar for all 4 methods. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that use of either hydrometer or the electronic refractometer was an acceptable method of screening colostrum for low IgG concentration; however, the manufacturer-defined scale for both hydrometers overestimated colostral IgG concentration. Use of weight of the first milking as a screening test to identify bovine colostrum with inadequate IgG concentration could not be justified because of the low sensitivity.

Identification of the most common cutaneous neoplasms in dogs and evaluation of breed and age distributions for selected neoplasms

OBJECTIVE-To identify the most common cutaneous neoplasms in dogs and evaluate breed and age distributions for selected neoplasms. DESIGN-Retrospective epidemiological study. SAMPLE-Records available through the Veterinary Medical Database of dogs examined at veterinary teaching hospitals in North America between 1964 and 2002. PROCEDURES-Information on tumor type and patient breed and age was collected. Incidence and odds ratios with 95% confidence intervals were calculated. RESULTS-Records of 1,139,616 dogs were reviewed. Cutaneous neoplasms were diagnosed in 25,996 of these dogs; records for the remaining 1,113,620 dogs did not indicate that cutaneous neoplasms had been diagnosed, and these dogs were considered controls. The most frequent age range for dogs with cutaneous neoplasms was 10 to 15 years. Lipoma, adenoma, and mast cell tumor were the most common skin tumor types. CONCLUSIONS AND CLINICAL RELEVANCE-Results supported previously reported data regarding cutaneous neoplasia in dogs but provided updated information on the most common skin tumors and on age and breed distributions.

Cutaneous Mast Cell Tumors in Cats: 32 Cases (1991-1994)

Case records of 32 cats with cutaneous mast cell tumors (CMCTs) were reviewed. Using the Patnaik system for grading canine mast cell tumors, the relationships between histopathological grade and patient survival time and tumor recurrence were examined. Tumor histopathological grade had no prognostic significance. One-, two-, and three-year tumor recurrence rates following surgical excision were 16%, 19%, and 13%, respectively. Incomplete excision was not associated with a higher rate of tumor recurrence.

Atypical Coccidiosis in South American Camelids

Reported clinical signs of coccidiosis in South American camelids include anorexia of a few days duration, sudden death, and diarrhea. Antemortem diagnosis of clinical coccidiosis is usually based on clinical signs and supported by detection of coccidial oocysts in feces. This report describes 2 atypical cases of coccidiosis in South American camelids that had no coccidial oocysts detected on antemortem fecal flotation, prolonged weight loss, and normal fecal consistency.

In vitro effects of lactoferrin on lipopolysaccharide-induced proliferation, gene expression, and prostanoid production by bovine peripheral blood mononuclear cells

OBJECTIVE To evaluate the effect of lactoferrin on lipopolysaccharide (LPS)-induced proliferation of bovine peripheral blood mononuclear cells (PBMCs), gene expression of inflammatory mediators, and production of prostanoids in vitro. SAMPLE POPULATION PBMCs isolated from 15 Holstein bull calves. PROCEDURES Mixed populations of PBMCs were isolated by differential centrifugation. Proliferation assays were conducted in 96-well plates designed to allow addition of lactoferrin (200 ng/mL) with and without LPS (1 microg/mL) in a checkerboard design. Incorporation of 3H-thymidine was used to determine proliferation of PBMCs. Prostaglandin E2 production was determined in culture-conditioned medium by use of enzyme immunoassay. Effects of lactoferrin on LPS-induced gene expression of cyclooxygenase (COX)-2 and matrix metalloproteinase (MMP)-9 were monitored by use of PCR assays. RESULTS Lactoferrin supplementation significantly reduced LPS-induced incorporation of 3H-thymidine and production of prostaglandin E2 by PBMCs. Lactoferrin reduced LPS-induced expression of COX-2 and MMP-9 mRNA. CONCLUSIONS AND CLINICAL RELEVANCE Lactoferrin reduced LPS-induced cellular proliferation, inflammatory mediator gene expression, and prostaglandin E2 production by bovine PBMCs in vitro. These effects may be beneficial in reducing the impact of endotoxemia in neonates.

The 14-3-3 cerebrospinal fluid immunoassay lacks utility in the diagnosis of clinical scrapie.

This study determined whether the immunoassay for cerebrospinal fluid 14-3-3 protein concentration was sensitive and specific in the diagnosis of naturally occurring clinical scrapie in sheep. Cerebrospinal fluid was collected from 9 sheep with the confirmed diagnosis of scrapie. Additionally, cerebrospinal fluid was collected from 13 clinically normal sheep, which originated from a closely monitored flock with no history of scrapie. Sensitivity and specificity were calculated using standard epidemiological methods. Cerebrospinal fluid immunoassay results did not differ significantly between positive and negative sheep. Test sensitivity varied from 0.55 to 0.66, depending on the choice of test endpoint. Test specificity varied from 0.30 to 0.77, depending on the choice of test endpoint. The 14-3-3 cerebrospinal fluid immunoassay appears to have no value in the diagnosis of clinical scrapie in sheep.

Clinical assessment of a chemosensitivity assay as a treatment planning tool for dogs with cancer.

This study evaluated the clinical utility of a commercially available chemosensitivity assay. In the first part of the study, tumor tissues from dogs with various malignancies were tested, and the dogs were treated with a mitoxantrone/cyclophosphamide combination protocol. Tumor response was evaluated and compared to the predicted response. Assay results were not a significant predictor of clinical response to chemotherapy or of survival time. In the second part of the study, assay results were used to direct therapy in dogs with refractory lymphoma. There was no significant correlation (p equals 0.323) between predicted response and case outcome.

Atypical lymphosarcoma in a cow

A FOUR-year-old Angus cow was presented for evaluation of a large mass in the ventral caudal cervical region. The mass was first observed by the owner the day before presentation. Two weeks prior to presentation, the cow delivered her third calf. The cow was dull and thin (body condition score 4/10). The respiratory rate was 40 breaths/min, the rectal temperature was 39 5°C and the heart rate varied from 96 to 60 beats/min during the physical examination. Rectal examination was normal. A firm mass extended from the left thoracic inlet rostral 40 cm in the left jugular furrow. The mass measured approximately 30 cm in a dorsoventral direction and extended outward from the normal cervical contour approximately 10 cm. The exact size of the mass could not be determined because palpation did not reveal the deep extent of the mass. Biopsy samples were obtained for histological examination and a serum sample was tested for antibodies against bovine leukosis virus (BLV). Haematology also was performed. Histological examination of biopsy samples revealed dense sheets of lymphoid cells occasionally supported by a scant reticular stroma and extensive replacement of skeletal muscle by tumour cells. The serum agar gel immunodiffusion (AGID) test for BLV was negative. Abnormal findings on haematological examination included mild anaemia (PCv 26 per cent) and hyperproteinaemia (8.7 g/dl). Total leucocyte, neutrophil, lymphocyte and monocyte counts were within normal ranges. No lymphocytes with abnormal morphology were observed in peripheral blood. Economically feasible and efficacious treatment was unlikely and as the cow was unlikely to pass post mortem slaughter examination she was returned to the care of her owner. The authors anticipated that the cows condition would deteriorate rapidly; however, the cow appeared comfortable and it was felt that continued nursing would benefit the calf. Eighteen days following the initial examination the cow was presented for euthanasia. The mass appeared as previously described and there was a moderate swelling (5 cm x 5 cm) in the intermandibular space. No other abnormalities were detected on physical examination. Intermittent bloat was observed and an indwelling ruminal trocar was placed to prevent ruminal tympany. Three days following presentation the cow was observed regurgitating and she was enthanased the following day. Temperature, pulse and respiratory rates were within normal limits. Post mortem examination revealed a large (40 cm x 33 cm x 20 cm) firm subcutaneous mass, primarily at the left thoracic inlet. The mass completely encompassed, but did not invade, the trachea and oesophagus, however adjacent cervical musculature was involved. The mass was mottled, pale, white-grey and red and the cut surface bulged and had multiple distinct yellow-brown areas surrounded by a thin rim of haemorrhage. Microscopic examina-