Segregation of natural and experimental gastrointestinal nematode infection in F2 progeny of susceptible Suffolk and resistant Gulf Coast Native sheep and its usefulness in assessment of genetic variation

Gastrointestinal nematode parasitism is a concern to small ruminants worldwide. Productivity has been compromised because such nematodes, particularly Haemonchus contortus, have developed resistance to available anthelmintics. Some sheep breeds and lines within breeds are relatively resistant to infection, a trait that may be useful for developing control strategies. Suffolk sheep, which are susceptible to infection, were crossed with Gulf Coast Native sheep, which are more resistant to infection, to produce F1 progeny. F1 rams were bred to F1 ewes which produced 227 F2 offspring. These F2 offspring were evaluated for variability in infection levels, based on fecal egg count (FEC) and blood packed cell volume (PCV), under two natural infection conditions (one at weaning and another after a summer grazing period) and one experimental infection. The range of both FEC and PCV was large for all three infection periods with annual variation. Overall, the range for the three infection periods, respectively, were 167-149,933, 0-31,400 and 17-114,667 eggs per gram (EPG) of feces and 8.7-37.0%, 7.3-33.0% and 8.3-36.0%. This segregation of infection is what would be expected of F(2) progeny from susceptible and resistant parent breeds. Heritabilities of FEC and PCV for the three infection periods, respectively, were 0.15, 0.29 and 0.12, and 0.11, 0.22 and 0.12. Based on segregation of infection, larger heritabilities and maternal environment effects that declined after weaning, the summer natural infection was probably the best model for assessing genetic variation.     

Interstitial nephritis in cats inoculated with Crandell Rees feline kidney cell lysates

Parenteral administration of Crandell Rees feline kidney (CRFK) cell lysates or feline herpesvirus 1, calicivirus, and panleukopenia virus-containing vaccines (FVRCP) grown on CRFK cells induces antibodies against CRFK cells. These antibodies also react with feline renal cell extracts. The purpose of this study was to determine whether interstitial nephritis would be detected in cats that were immunologically sensitized with CRFK lysates, boosted with CRFK lysates, and then biopsied 2 weeks after the booster. Cats (2 per group) were immunologically sensitized against CRFK lysates by administering 10 microg, 50 microg, or 50 microg plus alum 13 times (12 times in the first 50 weeks) over 2 years. Two cats were inoculated three times, 4 weeks apart with an FVRCP vaccine for intranasal administration as kittens, boosted 50 and 102 weeks later, and then renal biopsies taken 2 weeks after the last booster. Neither of the cats vaccinated with the FVRCP for intranasal administration had detectable renal inflammation. One cat in each of the three CRFK lysate sensitization groups had lymphocytic-plasmacytic interstitial nephritis.     

Characteristics, prevalence and aetiology of lesions of the oral mucosa in adult sheep

A total of 214 sheep with lesions of the oral mucosa were recorded at the Veterinary Laboratories Agency regional laboratories between March 15, 2002 and February 28, 2003. Using denominator data from the scrapie abattoir survey a prevalence of 0.95 per cent (95 per cent CI 0.82 to 1.10 per cent) was recorded, and using the fallen stock survey a prevalence of 1.15 per cent (95 per cent CI 0.64 to 1.91 per cent) was recorded. The lesions varied widely and included dental pad lesions in 20 per cent of cases. In total, 248 sites were affected, the commonest being the lower gum below the incisors, which was affected in 100 sheep. Most of the lesions were 1 cm or less in diameter. Ninety per cent of the 251 lesions examined histologically were erosions, ulcers, healed ulcers, focal epithelial necrosis or haemorrhages, and the changes observed indicated that trauma was the most likely primary cause.     

Ability of a proteinase inhibitor mixture to kill poultry red mite, Dermanyssus gallinae in an in vitro feeding system

The development of a reliable in vitro feeding system has enabled the rapid testing of presumptive anti-mite factors, a mixture of protease inhibitors (PI), by incorporating these into the blood feed. Mites were collected from a caged-hen facility and underwent a regime of starvation under varying conditions of temperature and darkness to determine the optimum conditions that encouraged mites to feed in the in vitro system. The efficacy of two anti-coagulants, heparin (HS) and acid citrate glucose (ACD), on mite feeding rates and mortality was evaluated. The ability of a mixture of PI to kill mites was also evaluated. The rate of feeding was greater in mites that were starved and cooled for between 7 and 30 days compared with mites that were not starved or cooled. The percentage of mites that fed when presented with HS treated blood (70%) was greater when compared with ACD treated blood (48%). The mortality of mites fed blood treated with HS + PI increased to 45% compared with a mortality level of 5% in mites fed on blood treated with HS alone. A reliable in vitro method for feeding D. gallinae which has the potential to be used to rapidly screen blood-borne products for their efficacy in reducing mite numbers has been developed.     

Hypotensive infarction of the spinal cord in a rhesus macaque (Macaca mulatta)

A 6.5-year-old male rhesus macaque (Macaca mulatta) was presented with acute paraplegia following a surgical procedure. During surgery, he experienced an acute hypotensive episode that required 3 hours of supportive therapy before hemodynamic stability was restored. Paraplegia remained unchanged until euthanasia 72 hours later. At necropsy, spinal cord segments T10-S3 had acute, massive panmedullary necrosis, which involved most of the central and middle spinal cord, sparing the peripheral white matter. Additional lesions included arterial border zone necrosis of the brain, centrilobular hepatic necrosis, and proximal renal tubular necrosis. The histologic findings of central spinal cord necrosis with a preserved rim of white matter is consistent with severely decreased flow in the anterior spinal artery. Such lesions can result from episodes of generalized hypoperfusion. Possible factors contributing to the hypotensive episode in this case included the addition of xylazine to ketamine and atropine in the preanesthetic medication, positioning during anesthesia, and decreased blood pressure during surgery.     

Surgical treatment of adrenocortical tumors: 21 cases (1990-1996)

Twenty-four adrenocortical tumors were surgically removed from 21 dogs. Histopathological examination confirmed 18 carcinomas and six adenomas. Four dogs died in the perioperative period. Fifteen of the 17 dogs that survived the perioperative period had long-term resolution of their clinical signs. Two dogs with incompletely resected tumors were treated with mitotane to control their clinical signs. Overall median Kaplan-Meier life-table survival for dogs with carcinomas was 778 days (range, one to 1,593 days). Median survival for dogs with adenomas was not reached (range, 11 to 730 days). Histopathological diagnosis, histopathological cellular features, age of the dog, and tumor size were not prognostic of outcome.     

The amino acid profiles of the whole plant and of four plant residues from temperate and tropical forages

This study compared the amino acid (AA) profile of five residues (original forage, borate-phosphate buffer residue (BPR), neutral detergent fiber residue with (NDF+) and without (NDF-) sodium sulfite, and acid detergent fiber residue (ADF). Fourteen grasses and legumes from tropical and temperate regions were used in this study. The use of sodium sulfite did not affect the NDF concentration, but the NDF insoluble protein was lower (P < 0.05) in the NDF+ than in the NDF- (3.9 vs 4.5% DM, respectively). For all of the amino acids tested, the amino acid content, expressed as a percentage of CP, was lower in the ADF residue than in the original forage. There were no differences in the amino acid concentrations of the NDF- and NDF+ extracts (P > 0.05). Only in the case of methionine was there a difference in the amount of amino acid when the original forage was compared with the BPR (1.84 vs 1.45 % CP). When the AA profile of each residue was corrected for the AA content of the ADF, no difference was observed between the AA profile of the original forage and of the BPR (P > 0.05). Similar to the result without correction for the amino acids in ADF, the AA profiles of the NDF+ and NDF- fractions were similar (P > 0.05). From this result, we infer that the sodium sulfite had similar effects on all AA in the NDF residue that we tested. There were differences in amino acid concentrations in the original forage and the NDF residues for several amino acids (Met, Cys, Lys, Thr, Arg, Ile, Leu, and Phe) (P < 0.05). When the amino acid values of the original forage and the BPR were used with animal data in the Cornell Net Carbohydrate and Protein System model, few differences in animal predicted performance were evident. These findings suggest that the AA profile of the original forage can be used to predict the AA profile of the undegraded intake protein instead of using the borate-phosphate buffer residue for amino acid analyses. This would simplify obtaining feed amino acid values for use in the Cornell Net Carbohydrate and Protein System.     

Feline vaccine-associated fibrosarcoma: an ultrastructural study of 20 tumors (1996-1999)

Twenty feline vaccine-associated sarcomas were examined by transmission electron microscopy. Tumors contained pleomorphic spindle cells, histiocytoid cells, and giant cells. Most tumors contained myofibroblasts, which had morphologic features similar to those of fibroblasts. These cells were further distinguished by subplasmalemmal dense plaques and thin cytoplasmic actin myofilaments organized as elongated bundles concentrated at irregular intervals forming characteristic dense bodies. Intracellular crystalline particulate material was found in 5 of the 20 tumors. Energy dispersive X-ray spectroscopy was used to identify the crystalline material within one tumor as aluminum-based. One tumor from a feline leukemia virus-infected cat contained budding and immature retroviral particles.