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991.
Kingscote BF Wilson D 《The Canadian veterinary journal. La revue veterinaire canadienne》1986,27(11):440-442
Abortions occurred in 18% of 131 beef cows and heifers during two months, on a farm in southern Saskatchewan. The losses began two weeks after acute febrile illness and agalactia in a dairy cow to which the beef herd had been exposed. A diagnosis of Leptospira interrogans serovar pomona infection was made on the basis of serology in cows and the finding of leptospires in fetal tissues by fluorescent antibody test. Tentative diagnosis of infectious bovine rhinotracheitis delayed treatment and prophylaxis until infection attained high intensity in the herd and severe losses to the farmer occurred. Abortions ceased after vaccination against pomona and oxytetracycline treatment of pregnant cows, although chronic debility followed the acute phase of the disease in some cows. Recrudescence of infection was suspected four months later, when acute agalactia occurred in one cow and debility in calves and cows was recurring. Pomona infection was not proven, but dihydrostreptomycin treatment and revaccination were applied to the whole herd. Seroconversion and IgM antibody continued to indicate a persistent source of infection and susceptibility in a minority of the population one year after onset. The source of the original infection is believed to have been a carrier beef cow, or a dairy cow which was leptospiruric at the time of contact with the beef herd. With the exception of one aborted calf, no evidence of pomona infection was found outside the farm, in cattle or wild mammals tested serologically within a radius of 30 km, during one year following the outbreak. 相似文献
992.
A ram lamb with congenital goitre showed signs of respiratory distress at birth. All previously affected lambs from this flock bad been born dead or bad died soon after birth. The serum free-thyroxine level at 1 birth was low (9.8 pmol/l) but treatment with oral L-thyroxine resulted in an increase in thyroxine blood levels to above normal and regression of the goitre. Four weeks after withdrawal of thyroid supplementation and when the lamb was eight weeks old, the radio iodide uptake mechanism of the thyroid glands was shown to be intact but the iodide was not organified. Low normal peroxidase activity was demonstrated in fresh thyroid tissue but gel electrophoresis demonstrated an absence of normal thyroglobulin from extracts of the goitrous thyroid. This lamb and the other affected lambs of this flock have an inherited defect in thyroglobulin synthesis and it is likely that the respiratory distress was associated with the low levels of thyroid hormone affecting foetal lung development. 相似文献
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996.
On a property in the Nelson District, blood and urine samples were taken from red deer (Cervus elaphus) from which low (<1:100) antibody titres to serovar copenhageni and suspected leptospiral abortions had previously been reported. A total of 27 hinds were sampled. Microscopic agglutination test (MAT) titres in sera ranging from 1:32 to 1:128 were found in six animals. Thirteen leptospiral isolations were made from nine of the 27 urine samples. Four of these were typed as copenhageni and nine as hardjo. Two cultures were prepared from each urine sample and hardjo and copenhageni were both isolated from single urine samples from two animals. None of the 27 deer had serum MAT titres at 1:32 or above to copenhageni. 相似文献
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998.
999.
E T Kornegay J B Meldrum G Schurig M D Lindemann F C Gwazdauskas 《Journal of animal science》1986,63(2):484-491
Three trials using 240 weanling pigs were conducted during winter months to determine the influence of nursery temperature ("comfortable" vs "cold") on the response of weanling pigs to added vitamin C (700 ppm) or E (55 IU/kg) to a corn-soybean meal diet. A "comfortable" temperature schedule (27 C initially with a weekly 2 C drop) was maintained in one nursery, with the temperature schedule in the "cold" nursery about 8 C lower. Plasma concentrations of vitamin C and vitamin E were elevated when the respective vitamins were added to the diet, but were not consistently influenced by nursery temperatures. Daily gain, daily feed intake and feed efficiency were not improved with the added C or E. Daily feed intake was increased and feed-to-gain ratios were larger for pigs housed in the "cold" nursery compared with pigs housed in the "comfortable" nursery; however, daily gains were similar in the two environments. Pigs housed in the "cold" nursery were slightly stressed, as indicated by heavier adrenal glands, but the antibody response and serum glucocorticoid concentrations were not significantly affected by either diet or temperature. 相似文献
1000.
A path model of factors influencing morbidity and mortality in Ontario feedlot calves. 总被引:2,自引:1,他引:1
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The principles of path analysis and causal modelling are discussed. Path analysis was applied to three data sets to assess the relationship between group characteristics (number per group and "mixing" subgroups of cattle, feeding-management of the group and processing factors (vaccination and prophylactic antimicrobials) and subsequent morbidity and mortality in feedlot cattle. The major findings agree with previously reported results but the timing and pathways of the effects are elaborated. In general, morbidity in week 1 was correlated with morbidity in week 2, which was correlated with morbidity in weeks 3-5. The same was generally true for mortality. In general, morbidity was not strongly correlated with mortality. Lots (unmixed groups) did not arrive in better condition, but experienced fewer subsequent health problems than mixed groups. (Silage-fed lots appeared to do poorly, however this was apparently due to the positive association between lots and vaccination, the latter being detrimental to mortality rates.) The more cattle per group, the greater the health problems in weeks 3-5 postarrival. Prophylactic antimicrobials in the water supply on arrival lead to increased health problems in the three to five week postarrival period. Antibiotic containing starter rations had a beneficial effect on health status in this period. This effect appeared to be partly due to delaying making silage the major ration component in silage-fed cattle receiving antimicrobial containing starter rations. Vaccination against respiratory disease in either of the first two weeks postarrival had detrimental direct and indirect effects on subsequent health status. Vaccination during weeks 3-5 postarrival was not significantly related to health status in that period. 相似文献