首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
2.
Extract

Many flocks were examined regularly to assess ram fertility, from 1948 to 1950 inclusive, as a service to members of the Gisborne Veterinary Club. The presence of Chorioptes bovis as a cause of scrotal mange was detected, and its widespread occurrence established. Surveys of ram fertility were again made in the Gisborne-East Coast area in February, March and May 1951 and, in addition to noting the size and condition of the testicles and the absence or presence of scrotal mange, samples were taken to prove the presence of chorioptic mites. The findings of these studies are reported and show evidence of an association between reduced testicular size and chorioptic mange of the scrotum of rams.  相似文献   

3.
4.
5.
6.
Survival of Aujeszky's disease virus in pig slurry was investigated during anaerobic storage at 5, 20, 35, 40, 45, 50 and 55 degrees C using 100-ml laboratory models simulating the conditions in slurry tanks during winter and summer seasons and during anaerobic digestion in batch reactors. The inactivation rate was found to increase with increasing temperature. Virus was inactivated at 5 and 20 degrees C in 15 weeks and 2 weeks, respectively. At 35 degrees C (mesophilic conditions) the virus was inactivated in 5 hours and at 55 degrees C (thermophilic conditions) no virus could be detected after 10 minutes.  相似文献   

7.
8.
通过调查,我们发现,为保证孵化室的温度条件,我国北方地区的孵化场冬季多采用锅炉+传统暖气片供暖,使用煤或锯末做燃料。这种供暖方式,寒冷季节可以保证孵化室的温度满足孵化需要,但室内温度不均衡,且不节能。  相似文献   

9.
10.
11.
The objective was to determine scrotal and testicular temperatures in rams and how they are affected by ambient temperature (10 degrees C vs 25 degrees C) and scrotal fleece (densely fleeced vs shaved). Scrotal surface temperatures (SST) of the caudal aspect of the shaved hemi-scrotum at 10 degrees C vs 25 degrees C were (mean, degrees C) 28.9 and 30.5 (P < 0.03), 28.2 and 29.6 (P < 0.04), and 26.1 and 27.6 (P < 0.06) at the top, middle and bottom of the testis, respectively. Scrotal subcutaneous temperatures (SQT) on the fleeced vs shaved side were 33.5 and 32.0 (P < 0.02), 32.2 and 31.1 (P < 0.06), and 31.7 and 30.8 (P < 0.09) at the top, middle, and bottom at 10 degrees C; they were 33.9 and 32.1 (P < 0.02), 33.1 and 31.9 (P < 0.05), and 32.5 and 32.0 (P < 0.15) at 25 degrees C. Intratesticular temperatures (ITT; measured only at 25 degrees C) on the fleeced vs shaved side were 35.3 and 35.0 (P < 0.5), 35.5 and 35.2 (P < 0.4), and 35.4 and 35.0 (P < 0.3) at the top, middle, and bottom. Temperature gradients (difference from top to bottom) were greatest for SST (2.8 degrees C), moderate for SQT (1.8 to 0.1 degrees C), and not significant for ITT (-0.1 and 0.1 degrees C). The SST was approximately 1.5 degrees C warmer at all 3 locations at 25 degrees C vs 10 degrees C. Increased ambient temperature affected SQT more at the bottom than at the top. Conversely, the difference in SQT between the fleeced and shaved sides was greatest at the top. The difference in ITT (0.3 degrees C warmer on the fleeced vs the shaved side at all locations) was not significant. Therefore, the magnitude of temperature increase associated with ambient temperature or scrotal fleece was affected by both depth and vertical location.  相似文献   

12.
Bovine viral diarrhea virus (BVDV) is a pestivirus that is enzootic in most cattle populations throughout the world. This virus is present throughout the body of persistently infected (PI) cattle. Previous research has not assessed the cooking temperature at which BVDV in meat from PI cattle can be inactivated. Therefore, muscle tissue from 6 PI cattle was harvested, refrigerated, frozen, and heated to various internal temperatures. The concentration of virus present was determined by virus isolation. Average cell culture infective doses (50% endpoint; CCID(50)) of BVDV per gram of frozen, uncooked meat from PI cattle were 10(5.85) CCID(50)/g of whole cuts and 10(6.02) CCID(50)/g of ground meat. The virus in whole and ground meat was consistently inactivated when cooked to temperatures greater than or equal to 75°C. A second objective of this research was to thoroughly reassess if Vero cells were permissive to BVDV infection in our laboratory to provide further indication of whether primates, including humans, might be susceptible to BVDV. Vero cells were not permissive to infection with any of 43 different strains of BVDV that readily replicated in Madin Darby bovine kidney cells. In conclusion, this bovine pathogen, which is not considered to be a human pathogen, can be inactivated by cooking ground or whole cuts of meat to 75°C or higher. Care should be taken to ensure that susceptible hosts such as pigs are not fed improperly cooked meat, meat by-products, or waste food originating from PI cattle.  相似文献   

13.
14.
Summary The sweating and respiratory rates in rams of Rambouillet (R), Chokla (C), Malpura (M), R × C and R × M breed/breed crosses were recorded when housed in sheds or exposed to 20, 25, 30, 35 and 42°C ambient temperatures in a climatic chamber. The sweating (cutaneous moisture) was higher (P<0.05) in Rambouillet and its crosses than the natives, the Malpura sheep producing the least sweat at all temperatures. There was no breed difference in the response of increase in sweating up to 35°C but at 42°C the Chokla showed a considerable increase. Sweating was more pronounced on the shoulder than on the mid-side region. Sweating and respiratory rates increased (P<0.05) with the increase in ambient temperature. The Rambouillet exhibited the highest increase in respiration rate at 25°C and the trend continued up to 42°C. The relationship between fleece characteristics, evaporative heat loss and heat tolerance of sheep is discussed.
Perdida Cutanea De Agua Y Frecuencia Respiratoria De Varias Razas De Ovejas Sometidas A Temperaturas Ambientales Altas
Resumen Se registraron las frecuencias sudorípara y respiratoria en carneros de las razas Rambouillet (R), Chokla (C), Malpura (M), R × C y R × M, alojados en cobertizos o expuestos a temperaturas ambientales de 20, 25, 30, 35 y 42°C en una cámara climática. El sudor (humedad cutánea) fue mayor (P<0.05) en carneros Rambouillet y sus cruces que en animales nativos, siendo la raza Malpura la que menos sudor produjo bajo todas las temperaturas. No se presentaron diferencias significativas entre las diferentes razas respecto a la humedad cutánea hasta los 35°C, pero a los 42°C la raza Chokla presentó un aumento considerable. El sudor fue más notorio en la espalda que en la región média. Las frecuencias respiratoria y sudorípara aumentaron (P<0.05) directa y paralelamente a la temperatura ambiental. La raza Rambouillet tuvo la frecuencia respiratoria más alta a los 25°C, incrementandose esta paulatinamente hasta los 42°C. Se discute la relación entre las caracteristicas del vellon, la pérdida de calor por evaporación y tolerancia al calor de las ovejas.

Niveau Des Pertes D'eau Par Transpiration, Et Rhythme Respiratoire De Differentes Races De Moutons Soumis A Des Temperatures Ambiantes Elevees
Résumé Les pertes par transpiration et le rythme respiratoire de béliers de Rambouillet (R), Chokla (C), Malpura (M) et de croisements R × C et R × M ont été relevés lorsque les animaux étaient en bergerie ou exposés à des températures ambiantes, dans une chambre climatique, à 20, 25, 30 et 42°C. Les pertes d'eau par transpiration ont été plus importantes (P<0.05) chez les mérinos de Rambouillet et les métis par rapport aux animaux de race locale, les Malpura manifestant les déperditions d'eau moindre à toutes les températures.Il n'y a pas eu de différences raciales dans la réponse à l'accroissement de la transpiration jusqu'à 35°C mais à 42°C les Chokla ont manifesté une augmentation considérable.La déperdition d'eau par transpiration cutanée a été plus prononcée au niveau des épaules que sur le côté du milieu du corps. La transpiration et le rythme respiratoire ont augmenté (P<0.05) avec l'accroissement de la température ambiante. Les mérinos de Rambouillet ont montré la plus importante augmentation du rythme respiratoire à 25°C, température qui a continué de s'accroître jusqu'à 42°C, limite supérieure de l'expérimentation.Les relations entre l'influence de la température sur les pertes d'eau par évaporation et al tolérance des moutons à la chaleur sont discutées.
  相似文献   

15.
16.
17.
18.
Multiparous Suffolk and Suffolk-cross ewes were randomly allotted to treatments within breed and year to measure effects of ram exposure, during transition from anestrus to breeding activity, on reproductive performance. Treatments were: 1) ewes joined with two mature vasectomized Rambouillet rams for 15 d before breeding (DC), 2) ewes maintained across a net wire fence from two vasectomized rams for 15 d before breeding (FC) and 3) ewes maintained approximately 400 m away from rams (NC). At the end of the 15 d, all ewes were placed in one pasture and mated to three fertile Suffolk rams during a 34-d breeding season. A total of 96 Suffolk and 177 Suffolk-cross ewes was utilized during the 3-yr experiment. A greater (P less than .05) prebreeding ovulation percentage was observed in DC and FC than in NC ewes. Mating and lambing occurred approximately 6 d earlier for DC or FC ewes than for NC ewes. A similarly designed experiment was conducted using Suffolk and Suffolk-cross ewe lambs allotted to treatments within breed and year to measure effects of ram exposure during the natural breeding season, but prior to breeding. Treatment differences were not detected (P greater than .05) for date of first observed estrus, date of lambing, percentage of ewes lambing in the first 17 d of the lambing season, number of lambs born per ewe lamb exposed or number of lambs born per ewe lamb giving birth.  相似文献   

19.
20.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号