Toxic shock syndrome in a horse with Staphylococcus aureus pneumonia

A 3-year-old Thoroughbred gelding was examined because of clinical signs of pneumonia and shock. Mucous membrane petechiation and ventral edema were observed and considered to be a result of vasculitis. Epidermal necrosis developed on the distal portions of the limbs. The horse had a persistent high fever that was unresponsive to nonsteroidal anti-inflammatory treatment, and Staphylococcus aureus was isolated from a nasal swab specimen and 2 transtracheal wash fluid samples. Antimicrobial, anti-inflammatory, and supportive treatment resulted in clinical improvement. However, resolution of the pulmonary infection required long-term (42 days) antimicrobial administration. Staphylococcus aureus strains isolated from this horse were positive for the toxic shock syndrome toxin-1 gene and were shown to produce toxic shock syndrome toxin-1, the causative factor in toxic shock syndrome in humans. The horse's clinical signs were attributed to toxic shock syndrome secondary to pulmonary S. aureus infection.     

COMBINED USE OF ULTRASONOGRAPHY AND CONTRAST ENHANCED COMPUTED TOMOGRAPHY TO EVALUATE ACUTE NECROTIZING PANCREATITIS IN TWO DOGS

The imaging findings in two miniature schnauzers with acute necrotizing pancreatitis are described. Both dogs were treated previously for diabetes mellitus and hyperlipidemia. Vomiting, anorexia, and lethargy were observed in both dogs at presentation. Laboratory evaluations supportive of pancreatitis included left shift, abnormally high serum amylase and lipase activities, hypocalcemia, and abnormally high serum activities of liver enzymes. Sonographically, both dogs had diffusely enlarged hypoechoic pancreatic tissue with anechoic foci compatible with necrosis, abscessation, phlegmon, and pseudocysts formation. Contrast-enhanced computed tomography (CT) findings in both dogs were compatible with pancreatic necrosis. Dog 1 was managed medically for 11 days. Follow-up CT scan in this dog disclosed decreased pancreatic size and increased contrast enhancement compatible with partial resolution of pancreatitis.     

Evaluation of the South African Dorper as a terminal sire breed for growth,carcass, and palatability characteristics

The South African Dorper is an important terminal meat sire breed in Africa that was recently imported into the United States. The objective of this study was to evaluate the Dorper as a terminal meat sire breed for U.S. production. Semen from purebred Dorper sires was used to artificially inseminate Columbia ewes to produce F1 crossbred lambs. Growth and carcass characteristics of F1 Dorper-Columbia lambs (n = 165), F1 Suffolk-Columbia (n = 89), and purebred Columbia lambs (n = 207) were compared based on subsets of the total number of animals. The F1 Dorper lambs grew significantly slower (313 g x d(-1)) and weighed less (29.8 kg) than F1 Suffolk- (357 g x d(-1), 33.5 kg) and Columbia-sired lambs (328 g x d(-1), 31 kg) at 77 d of age. However, at a weaning age of 118 d weaning weight and ADG did not differ (P > 0.20) among sire breed groups. Postweaning growth of F1 Dorper(239 g xd(-1)) wether lambs did not differ from that of purebred Columbia wethers (230 g x d(-1)) but was less than that of F1 Suffolk lambs (259 g x d(-1); P= 0.09). Feed efficiency did not differ among breed types. Breed types had similar dressing percentages (53%), shoulder fat depth (2.8 mm), body wall thickness (3 cm), leg conformation score (Choice), Yield grade (2.4), and Quality grade (Choice). Weight of wholesale shoulders and racks made up approximately 38% of the carcass weight in the Columbia and F1 Suffolk-Columbia type but only 33% in the F1 Dorper-Columbia lambs. However, the more expensive wholesale loins from F1 Dorpers were heavier (P < 0.01) than the other breed types. Total weights of wholesale legs were similar among F1 Dorpers and F1 Suffolks but were heavier than those for the purebred Columbia (P < 0.05). Percentages of total wholesale primal cuts were similar among breed types (P > 0.10). Chemical composition of the carcass did not differ significantly between breed types with a mean composition of 52% moisture, 30% lipid (ether extract), 17% protein, and 0.76% ash. Warner-Bratzler shear force values were less (P < 0.05) and sensory panel ratings for tenderness were significantly more favorable for lamb chops from Dorper sired lambs. Dorper rams can be used as terminal meat sires to produce lambs whose growth rate to 118 d of weaning age, postweaning ADG and feed efficiency, and carcass characteristics are similar to that of Suffolk crossbred lambs and purebred Columbia lambs but with a slight improvement in tenderness.     

Estimation of linkage disequilibrium in a sample of the United Kingdom dairy cattle population using unphased genotypes

The association between genetic marker alleles was estimated for two regions of the bovine genome from a random sample of 50 young dairy bulls born in the United Kingdom between 1988 and 1995. Microsatellite marker genotypes were obtained for six markers on chromosome 2 and seven markers on chromosome 6, spanning 38 and 20 cM, respectively. Two different methods, which do not require family information, were used to estimate population haplotype frequencies. Haplotype frequencies were estimated for pairs of loci using the expectation-maximization algorithm and for all linked loci using a Bayesian approach via a Markov chain-Monte Carlo algorithm. Significant (P = 0.0007) linkage disequilibrium was detected between pairs of loci in syntenic groups (that is, loci in the same linkage group), extending to about 10 cM. No significant linkage disequilibrium was detected between markers in nonsyntenic regions. Given the observed level of linkage disequilibrium, mapping methods based on population-wide association might provide a better resolution than traditional quantitative trait loci mapping methods in the U.K. dairy cattle population and may reduce the required sample sizes of the experiments.     

Strategies to reduce feedlot cattle heat stress: effects on tympanic temperature

Three experiments were conducted to evaluate the effect of different management strategies on body temperature of feedlot steers finished in the summer months. In Exp. 1, 24 crossbred steers were chosen to assess the effect of altered feed intake and feeding time on tympanic temperature (TT) response. Managed feeding (MF) treatments were applied for 22 d only and provided 1) ad libitum access to feed at 0800 (ADLIB), 2) feed at 1600 with amount adjusted so that no feed was available at 0800 (BKMGT), 3) feed at 1600 at 85% of predicted ad libitum levels (LIMFD). During heat stress conditions on d 20 to 22 of MF, LIMFD and BKMGT had lower (P < 0.05) TT than ADLIB from 2100 through 2400. A carryover effect of limit-feeding was evident during a severe heat episode (d 36 to 38) with LIMFD steers having lower (P < 0.05) TT than ADLIB. In Exp. 2, TT were obtained from 24 crossbred steers assigned to three treatments, consisting of no water application (CON), water applied to feedlot mound surfaces from 1000 to 1200 (AM) or 1400 to 1600 (PM). From 2200 to 0900 and 1200 to 1400, steers assigned to morning sprinkling treatment had lower (P < 0.05) TT than steers assigned to afternoon sprinkling treatment. In Exp. 3, 24 steers were utilized in a 2 x 2 factorial arrangement of treatments with factors of feeding time [0800 (AMF) and 1400 (PMF)] and sprinkling (WET and DRY). Tympanic temperatures were monitored under hot environmental conditions on d 30 to 32 and 61 to 62. A feeding time x sprinkling interaction (P < 0.001) was evident on d 30 to 32, although AMF/DRY steers had the highest (P < 0.05) TT. On d 61 to 62, TT of PMF steers was higher (P < 0.05) than AMF between 1500 to 1800. Use of sprinklers can effectively reduce TT of feedlot cattle, whereas shifting to an afternoon vs morning feeding time was most beneficial when bunks were empty several hours prior to feeding.     

Canine cyclic hematopoiesis: blood gas and 2,3-diphosphoglyceric acid studies

Cyclic hematopoiesis in gray Collies was first described in 1967. These dogs are anemic in comparison with the healthy littermates, and their erythropoiesis is abnormal. Although the basic disorder appears to be an as yet unidentified abnormality of hematopoietic progenitor cells, an inherent difference in responses to blood gas control mechanisms remains as a possible cause. In a study of these mechanisms in dogs with cyclic hematopoiesis, the P50 and 2,3-diphosphoglyceric acid concentrations were increased. Differences in pH, PCO2, PO2, and oxygen saturation were not observed.     

Chicken anemia agent: an electron microscopic study

Particles of chicken anemia agent (CAA) negatively stained with uranyl acetate were found to be 26.5 nm in diameter. The surface detail evident on the particles indicated that the virus capsid was composed of 32 structural subunits arranged as in a class P = 3 icosahedron with a triangulation number of 3. Using mouse monoclonal antibodies to CAA and a gold-labeled goat anti-mouse IgG, CAA-specific structures were observed by thin-section electron microscopy in infected MDCC-MSB1 cells and in thymic lymphocytes from experimentally infected chicks. These consisted of electron-dense, granular, non-membrane-bound nuclear inclusions, which were often ring-shaped, and cytoplasmic accumulations of microtubules. Aggregates of virus-like particles were sometimes observed in the nuclei of infected MDCC-MSB1 cells. The nucleolar involvement that is characteristic of the morphogenesis of parvoviruses was not observed with CAA.