Endotoxin-induced bovine mastitis: immunoglobulins, phagocytosis, and effect of flunixin meglumine

Milk whey immunoglobulins (Ig) and phagocytosis of staphylococci by milk polymorphonuclear neutrophilic leukocytes (PMN) were measured in 12 cows (allotted to 6 pairs) during acute bovine mastitis induced by intramammary inoculation of endotoxin. Six of these cows (or 1 in each pair) were treated with flunixin meglumine and were compared with the others (given only saline solution). The endotoxin inoculation comprised 10 micrograms of Escherichia coli O26:B6 lipopolysaccharide injected into one of the rear quarters (mammae). Flunixin meglumine was administered parenterally at a dosage of 1.1 mg/kg every 8 hours (total of 7 doses) beginning at 2 hours after endotoxin was injected. Milk samples were obtained, and whey samples were prepared from each quarter of each cow 3 times before inoculation and at 2, 4, 8, 12, 24, 48, 72, 96, 120, 144, 168, and 336 hours after endotoxin was inoculated. Significant increases (P less than 0.05) in milk whey IgG1, IgG2, IgM, and IgA concentrations were observed in whey samples from endotoxin-inoculated quarters. Greatest relative increase was seen for IgG2. Increased whey Ig concentrations were not observed in quarters which were not inoculated with endotoxin. Concentrations of whey IgG1 and IgM in endotoxin-inoculated quarters were significantly (P less than 0.05) decreased in flunixin meglumine-treated cows, compared with those in saline solution-treated cows. Significant increases in phagocytosis of staphylococci by milk PMN were observed in whey samples from endotoxin-inoculated quarters. Significant differences in PMN phagocytosis were not found in whey samples from cows given flunixin meglumine when compared with whey samples from cows given saline solution.     

Evaluation by scoring and computerized morphometry of lesions of early Mycoplasma pulmonis infection and ammonia exposure in F344/N rats

To evaluate lesions of ammonia exposure and Mycoplasma pulmonis infection in gnotobiotic F344/N rats, groups of rats were inoculated with M. pulmonis, exposed to 76 micrograms/liter (100 parts per million) ammonia, or both, or served as controls. Six rats from each group were killed 3, 5, 7, and 9 days after inoculation and their respiratory organs prepared for histologic examination. Lesions were assessed by subjective scoring and computerized morphometry, and results obtained by the two methods were compared to assess agreement of results. Lesions were limited to the nasal passages. Ammonia exposure resulted in hyperplastic and degenerative changes in the anterior nasal epithelium. Lesions of mycoplasmosis were more severe in ammonia-exposed than unexposed rats, but qualitative differences in lesions were not apparent. Results of the two methods agreed in assessment of submucosal inflammatory cell accumulation. Epithelial lesions were difficult to evaluate by both methods in infected, ammonia-exposed rats. In evaluation of lesions of ammonia exposure alone, agreement was adequate. Both methods indicated that exudates were significantly greater in ammonia-exposed infected rats than in non-exposed infected rats. Thus, scoring and morphometry provided similar assessments of differences in lesion severity among the treatment groups.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

Pharmacokinetics and pharmacodynamics of three formulations of firocoxib in healthy horses

The objectives of this study were to compare the pharmacokinetics and COX selectivity of three commercially available formulations of firocoxib in the horse. Six healthy adult horses were administered a single dose of 57 mg intravenous, oral paste or oral tablet firocoxib in a three‐way, randomized, crossover design. Blood was collected at predetermined times for PGE₂ and TXB₂ concentrations, as well as plasma drug concentrations. Similar to other reports, firocoxib exhibited a long elimination half‐life (31.07 ± 10.64 h), a large volume of distribution (1.81 ± 0.59L/kg), and a slow clearance (42.61 ± 11.28 mL/h/kg). Comparison of the oral formulations revealed a higher C_max, shorter T_max, and greater AUC for the paste compared to the tablet. Bioavailability was 112% and 88% for the paste and tablet, respectively. Maximum inhibition of PGE₂ was 83.76% for the I.V. formulation, 52.95% for the oral paste formulation, and 46.22% for the oral tablet formulation. Pharmacodynamic modeling suggests an IC₅₀ of approximately 27 ng/mL and an IC₈₀ of 108 ng/ mL for COX2 inhibition. Inhibition of TXB₂ production was not detected. This study indicates a lack of bioequivalence between the oral formulations of firocoxib when administered as a single dose to healthy horses.     

Renal osteodystrophy with facial hyperostosis and ‘rubber jaw’ in an adult dog

A nine-year-old male Sheltie dog was presented with bilaterally symmetrical maxilliary swelling, loose teeth and flexible mandibles. The condition was progressive over a period of two months. Biochemical and histopathological examinations supported a diagnosis of renal osteodystrophy with facial hyperostosis and ‘rubber jaw’.     

Pharmacokinetics of firocoxib after intravenous administration of multiple consecutive doses in neonatal foals

The purpose of this study was to determine the pharmacokinetic profile of intravenous firocoxib in neonatal foals. Six healthy foals were administered 0.09 mg/kg firocoxib intravenously once a day for 7 days. Blood was collected for plasma firocoxib analysis using high‐performance liquid chromatography with fluorescence detection at times 0 (day 1 of study only) and 0.08, 0.25, 1, 2, 4, 6, 8, 16 and 24 hr on dose numbers 1, 5 and 7. Blood was also collected immediately prior to doses 3, 4, 5 and 7. Final samples were collected at 36, 48, 72 and 96 hr following the final dose. Noncompartmental analysis using the trapezoidal method with linear interpolation revealed a moderate half‐life (15.9 ± 9.1 hr) with a large volume of distribution at steady state (1.79 ± 0.57 L/kg) and a clearance (96.0 ± 59.2 ml h^?1 kg^?1) that was more rapid than that observed in adult horses.     

Efficacy of ivermectin in the treatment of induced Parascaris equorum infection in pony foals

Eighteen pony foals inoculated with 1,500 +/- 109 infective Parascaris equorum eggs were given 0.02 ml of ivermectin vehicle (liquid)/kg of body weight, PO, (control); 0.2 mg of ivermectin paste/kg, PO; or 0.2 mg ivermectin liquid/kg, PO, on postinoculation day (PID) 28. Foals were euthanatized on PID 42, and the small intestinal contents were examined for P equorum larvae. The mean number of fourth-stage P equorum larvae in foals treated with ivermectin paste and liquid were 3.5 and 6, respectively. Significantly (P less than 0.01) higher mean numbers of larvae (1,250) were detected in foals treated with ivermectin vehicle. Larvae recovered from foals treated with ivermectin vehicle were of significantly (P less than 0.002) longer mean length than those from foals treated with ivermectin paste or liquid. Gross examination of lungs and liver revealed similar pathologic changes from the migration of P equorum in all foals. Adverse reaction to treatment was not observed.     

Impact of blood serum insulin-like growth factor I on platelet-activating factor in bull spermatozoa

The objective of this study was to examine differences in platelet-activating factor [1-O-alkyl-2-acetyl-sn-glycero-3-phosphorylcholine; PAF] in spermatozoa between two lines of Angus beef cattle divergently selected for blood serum insulin-like growth factor I (IGF-I) concentration. Endogenous lipids were extracted from the spermatozoa and endogenous PAF content was determined by radioimmunoassay. The amount of PAF detected in spermatozoa obtained from high IGF-I bulls (n = 8) ranged from 0.145 to 3.571 pM/10(6) cells. The level of PAF extracted from spermatozoa obtained from low IGF-I- bulls (n = 5) ranged from 0.001 to 1.024 pM/10(6) cells. Polynomial regression analysis revealed a significant cubic relationship (R(2) = 0.374; F = 6.292; P < 0.05) between spermatozoa PAF content and blood serum IGF-I concentration. Spermatozoa-derived PAF levels (mean +/- SEM) were significantly higher (P < 0.05) in the high IGF-I group (1.90 +/- 0.39 pM/10(6) cells) than in the low IGF-I group (0.59 +/- 0.20 pM/10(6) cells). High IGF-I bulls have a greater than three-fold higher PAF content in their spermatozoa than low IGF-I bulls. The data demonstrate that not only is PAF present in bull spermatozoa but that levels are significantly higher in individuals with high serum IGF-I concentrations.     

Epidemiology and control of Menangle virus in pigs

OBJECTIVE: To describe the epidemiology and eradication of Menangle virus infection in pigs. DESIGN: Field observations and interventions, structured and unstructured serological surveys, prospective and cross-sectional serological studies and laboratory investigations. PROCEDURE: Serum samples were collected from pigs at a 2600-sow intensive piggery in New South Wales that experienced an outbreak of reproductive disease in 1997. Serum samples were also collected from piggeries that received pigs from or supplied pigs to the affected piggery and from other piggeries in Australia. Serum and tissue samples were collected from pigs at piggeries experiencing reproductive disease in New South Wales. Sera and faeces were collected from grey-headed flying foxes (Pteropus poliocephalus) in the region of the affected piggery. Serum samples were tested for neutralising antibodies against Menangle virus. Virus isolation was attempted from faeces. RESULTS: Following the outbreak of reproductive disease, sera from 96% of adult pigs at the affected piggery, including sows that produced affected litters, contained neutralising antibodies against Menangle virus. Neutralising antibodies were also detected in sera from 88% of finisher pigs at two piggeries receiving weaned pigs from the affected piggery. No evidence of Menangle virus infection was found in other piggeries in Australia. In cross-sectional studies at the affected piggery, colostral antibodies were undetectable in most pigs by 14 to 15 weeks of age. By slaughter age or entry to the breeding herd, 95% of pigs developed high antibody titres (> or = 128) against Menangle virus in the virus neutralisation test. Menangle virus was eradicated from the affected piggery following a program of serological testing and segregation. Neutralising antibodies against Menangle virus were also detected in P poliocephalus from two colonies in the vicinity of the affected piggery. Two piggery workers were infected with Menangle virus. There was no evidence of infection in cattle, sheep, birds, rodents, feral cats and a dog at the affected piggery. CONCLUSIONS: Serological evidence of infection with Menangle virus was detected in pigs at a piggery that had experienced reproductive disease, in pigs at two associated piggeries and in fruit bats in the region of the piggery. Two humans were infected. The mode of transmission between pigs is unknown, but spread by faecal or urinary excretion is postulated. This virus can be eradicated by the segregation of pigs into discrete age groups.     

Epidemiology and diagnosis of Mycobacterium tuberculosis in captive Asian elephants (Elephas maximus).

The deaths of two Asian elephants (Elephas maximus) in August 1996 led the United States Department of Agriculture to require the testing and treatment of elephants for tuberculosis. From August 1996 to September 1999. Mycobacterium tuberculosis infection was confirmed by culture in 12 of 118 elephants in six herds. Eight diagnoses were made antemortem on the basis of isolation of M. tuberculosis by culture of trunk wash samples; the remainder (including the initial two) were diagnosed postmortem. We present the case histories, epidemiologic characteristics, diagnostic test results, and therapeutic plans from these six herds. The intradermal tuberculin test, enzyme-linked immunosorbent assay serology, the blood tuberculosis test, and nucleic acid amplification and culture are compared as methods to diagnose M. tuberculosis infection in elephants.