Embryo transfer from cattle infected with bluetongue virus   总被引：1，自引：0，他引：1  

R A Bowen  T H Howard  R P Elsden  G E Seidel 《American journal of veterinary research》1983,44(9):1625-1628

Embryos recovered nonsurgically from donor cattle during the peak of bluetongue viremia were surgically transferred to seronegative recipients 7 to 8 or 10 to 11 days after the onset of donor estrus. Virus was isolated from the uterine flushing medium recovered from 11 of the 20 donors. Bluetongue virus was not isolated from the blood of any of 39 recipients, nor did any recipient seroconvert to the virus following transfer. The number of recipients that became pregnant after transfer of embryos from infected donors (21 of 39) was not significantly different from contemporary controls. Virus antigen was not detected by immunofluorescence in any of 63 embryos and oocytes recovered from viremic donors. These results indicate that under standard embryo transfer conditions, transmission of bluetongue virus from infected donors to uninfected recipients is unlikely to occur.  相似文献   

Acute viral hepatitis in California sea lions     

J O Britt  A Z Nagy  E B Howard 《Journal of the American Veterinary Medical Association》1979,175(9):921-923

Acute viral hepatitis was diagnosed in five California sea lions (Zalophus californianus) stranded along the Los Angeles coast. Light microscopy revealed large nuclear inclusion bodies in hepatocytes. Electron microscopy provided evidence that these inclusion bodies were composed of adenovirus-like virions. Attempts to grow the virus in cell culture systems were unsuccessful.  相似文献   

Isolation of Chlamydia psittaci from the genital tract of lambs: a possible link with enzootic abortion of ewes     

K L Morgan  J M Wills  P Howard  R L Williams 《The Veterinary record》1988,123(15):399-400

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Observations of infectious diarrhea as part of the shipping fever syndrome in feedlot cattle     

J R Howard 《Journal of the American Veterinary Medical Association》1969,154(10):1201-1202

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Increased Growth and Production of Striped Bass × White Bass Hybrids in Earthen Ponds     

J. Howard  Kerby  Jeffrey M.  Hinshaw Melvin T.  Huish 《Journal of the World Aquaculture Society》1987,18(1):35-43

Four 0.1 hectare earthen ponds were stocked with 16,500 hybrid striped bass (female Morone saxatilis × male M. chrysops ) per hectare on 22 June 1982. Mean weight at stocking was 5.2 g ± 0.10 SE. Fish were fed to satiation two or three times daily with a dry commercial salmonid diet, and the ponds were aerated mechanically during periods of low dissolved oxygen during warm weather. Survival at harvest on 6 March 1983 averaged 84.7%, and mean weight of the fish was 170.2 g ± 2.66 SE. Average weights of fish from individual ponds ranged from 149.0 to 189.7 g. The ponds were restocked on 1 April 1983 with 10,000 fish per hectare averaging 193.6 g. Ten months later, average survival in 3 ponds was 83.9% (range, 81.3–87.0%) and mean weight was 656.3 g ± 5.51 SE. Average weights of fish from individual ponds ranged from 632.5 to 690.7 g. All fish in one pond died in June as a result of an aerator failure. Standing crop at harvest in the three remaining ponds averaged 5, 504 kg/ha (range, 5,247–5,765 kg/ha). Improvements in culture techniques resulted in approximately a 138% increase in production per hectare over that reported in a prior study. Results demonstrated that hybrid striped bass offer considerable potential for commercial aquaculture in warm temperate latitudes of the United States.  相似文献   

Hydrolytic activation and detoxication of 2,4-dichlorophenoxyacetic acid esters in mosquito fish     

Howard Chambers  L.J. Dziuk  Jo Watkins 《Pesticide biochemistry and physiology》1977,7(3):297-300

Insecticide-resistant mosquito fish (Gambusia affinis) were found to be slightly more tolerant to two thiol esters of 2,4-dichlorophenoxyacetic acid (2,4-D) than were fish of a susceptible population. DEF (S,S,S,-tributyl phosphorotrithioate), at 0.1 ppm for 24 hr, slightly decreased the toxicity of both esters to both populations. Comparison of esterase activities in gill and liver preparations showed that the resistant fish had lower levels of liver esterases than the susceptible fish, but results with gill preparation were not consistent. With the ethyl thiol ester, susceptible fish had the higher activity, but with butyl thiol ester, resistant fish had the higher activity. DEF inhibited activities in both tissues of both populations, but inhibition was appreciably greater in the liver. Results suggest that (i) hydrolysis in the liver activaties 2,4-D esters, (ii) hydrolysis in the gill is a detoxication reaction, (iii) the slight increase in tolerance in the insecticide-resistant fish is primarily the result of decreased activation, and (iv) antagonism by DEF is the result of a greater inhibition of activation than of detoxication.  相似文献   

Method of Selecting Preferred Baits and Rodenticides1     

W.E. Howard  R.E. Marsh 《EPPO Bulletin》1977,7(2):459-463

To conduct bait-choice tests, with species that will enter bait boxes, requires at least 10 bait boxes (25–40 cm long and about 20 cm deep) with openings at opposite corners, for exposing 3 to 5 trays of potential baits. Floors of boxes are dusted with a thin layer of talc or ground clay. The same boxes can be used to determine acceptance of the proven preferred bait treated with different rodenticides at different concentrations, except that different toxicants cannot be compared in the same box unless only chronic (multiple-feeding) anticoagulants are used. Tracking tunnels or stations can be used to obtain a relative pre- and post-control census of rodent populations. They are especially useful for determining whether there are survivors. If there axe survivors, the above non-toxic bait-acceptance tests and acceptance of prepared toxic bait tests must be repeated, for it is paramount to learn why the survivors were not poisoned.  相似文献   

Rabies in a horse.     

R J Marler  D R Howard  P G Morris  J L Johnson 《Journal of the American Veterinary Medical Association》1979,175(3):293-294

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Effect of feeding frequency on forage fiber and nitrogen utilization in sheep     

L D Bunting  M D Howard  R B Muntifering  K A Dawson  J A Boling 《Journal of animal science》1987,64(4):1170-1177

Four crossbred wether lambs (38 kg) with permanent ruminal and abomasal cannulae were used in a 4 X 4 Latin square arrangement of treatments to determine the effect of feeding frequency (FF) on forage fiber and N utilization. Lambs were offered 900 g of good quality (vegetative) Kentucky-31 tall fescue hay in equal portions either 2, 4, 8 or 16 times daily. Water consumption increased (P less than .05; linear) with increased FF. Apparent total tract digestibilities of dry matter, organic matter and cell wall constituents were not affected (P greater than .05) by FF, but apparent total tract digestibility of crude protein decreased (P less than .05; linear) with increased FF. Ruminal and post-ruminal digestion of acid detergent fiber (percent of total tract digestion) differed (P less than .05; cubic) among FF treatments. Although N retention was not affected (P greater than .05) by FF, increased FF decreased (P less than .05; linear) mean ruminal ammonia-N concentrations. Both the quantity of total N reaching the abomasum and the efficiency of microbial crude protein synthesis tended to increase (P greater than .05) with increased FF. In addition, the daily quantity of microbial N reaching the abomasum was affected (P less than .05; cubic) by FF. Ruminal pH was not affected (P greater than .05) by FF, whereas total volatile fatty acid concentrations (VFA) decreased (P less than .05; linear) with increased FF. Responses in molar proportions of individual VFA to FF were variable, and suggest that increasing FF elicits significant changes in the distribution of fermentation end-products.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

Hypergammaglobulinemia in ferrets with lymphoproliferative lesions (Aleutian disease)   总被引：3，自引：0，他引：3  

A J Kenyon  E Howard  L Buko 《American journal of veterinary research》1967,28(125):1167-1172

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