Canadian journal of comparative medicine and veterinary science最新文献

Four experiments using weight gain, feed efficiency and carcass analysis criteria were conducted with 148 pigs to determine the effects of feeding nicotine sulfate at various levels on protein and fat deposition. A level of 5 p.p.m. of nicotine sulfate in the ration fed to pigs from weaning until market weight significantly decreased (P<.05) the depth of loin fat in two of three experiments in which it was tested and slightly increased the carcass protein: fat ratio in all experiments. A level of 20 p.p.m. was as effective as 5 p.p.m. but higher levels of 40 and 80 p.p.m. had no effect on carcass quality. The fat content of the livers of pigs fed 5 p.p.m. of nicotine sulfate was found to be 8 to 10 per cent higher than that of controls in the two experiments in which it was measured. Higher levels of nicotine had little or no effect on liver lipids. Plasma cholesterol levels of pigs were not increased by the feeding of nicotine sulfate at levels of 5, 20 and 80 p.p.m.

The transfer of maternal antibodies to Friesian and buffalo calves born of dams vaccinated against rinderpest was through colostrum only. Colostral antibody titers at the time of parturition were higher than the serum titer. Two hours after suckling, a high level of rinderpest neutralizing antibodies was detected in the sera of newborn animals. The half-life of maternal antibodies in buffalo and Friesian calves was found to be approximately 33 and 29 days respectively. By the age of 7-8 months, 60 per cent of buffalo calves and 80 per cent of Friesian calves had no detectable levels of rinderpest neutralizing antibody.

The effect on the plaque production of the Purdue strain of cytopathogenic virus from transmissible gastroenteritis of swine by 5-bromo-2'-deoxyuridine (BUDR), 5-iodo-2'-deoxyuridine (IUDR), actinomycin-D, puromycin, and amantadine-HCI (Symmetral) has been studied.Amantadine-HCI reduced the plaque-forming units of virus per ml by approximately 98%. Puromycin prevented almost all virus reproduction while actinomycin-D caused approximately a 22% reduction. Both IUDR and BUDR produced approximately a 20% increase in plaque-forming units of virus per ml. Swine testis cells stained with acridine orange early in the course of infection contained brick-red particles in the cytoplasm, indicative of a ribonucleic acid (RNA) type virus.

The effects of orally and/or parenterally administered immune serums were evaluated in 36 gnotobiotic pigs infected with an enteropathogenic strain of Escherichia coli. Pigs were euthanatized at predetermined time intervals between 6 and 48 hours prostinfection. The results were evaluated on the basis of: 1) clinical observations, 2) necropsy observations, 3) counts of viable E. coli in segments of the small intestine, 4) attempts to isolate E. coli from the heart, liver, and bile, 5) microscopic examination of fixed intestinal sections to determine the location of E. coli and morphologic evidence of the host response, and 6) determination of the pH of the various portions portions of the gastrointestinal tract. Orally administered immune serum completely protected the pigs from fluid loss and diarrhea. Parenterally administered serum did not protect against fluid loss into the intestinal lumen but diarrhea was not observed. The pH of the contents of the lumen of the cecum and colon was markedly elevated simultaneously with the accumulation of fluids and incompletely digested milk. The results of microscopic examination of tissues as well as other determinations did not reveal the mechanism of fluid loss nor the mechanism of protection afforded by orally administered immune serum. The results support the contention that continuous adequate levels of appropriate antibodies in the lumen of the intestinal tract aŕe a significant deterrant to the establishment of colibacillosis in baby pigs.

Specific antibodies are found in the globulin fraction of the milk following instillation of mumps virus in the mammary gland of the goat. These antibodies, conjugated with fluerescein isothiocyanate, have been successfully employed in the direct fluorescent antibody staining of mumps virus in infected BS-C-1 cells.

The properties of six pathogenic and six non-pathogenic strains of staphylococci from clinical cases of exudative epidermitis are described. The pathogenic strains were shown to produce typical lesions following experimental inoculation of pigs. All of the strains studied were classified among the staphylococci due to their ability to produce acid from glucose under anaerobic conditions. One of the six pathogenic strains was a slow coagulase producer. It is suggested that the species designation Staphylococcus hyicus be retained.

Reports of Cl. perfringens as a pathogen for cattle are reviewed and discussed.