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961.
Optical light, transmission, and scanning electron microscopy were used in investigations of epithelia in the glandular region of the milk cistern and greater lactiferous ducts and yielded the following findings, four and six hours from infection: degeneration and necrosis of epithelial cells, intraepithelial foreign cell infiltration (neutrophilic granulocytes, lymphocytes, macrophages), intra-epithelial oedema and locally delimited epithelial loss. The lesions differed by intensity in various regions, so that a distinction could be made among five froms of epithelial alterations. The epithelial cells revealed their capability of absorbing pathogenic material and storing it in cytoplasmic vacuoles. This was considered to reflect active involvement of epithelium in antibacterial defence, and consequently, to reflect the role played by epithelium as a defence barrier in the milk cistern and greater lactiferous ducts. 相似文献
962.
The pathogenesis of velogenic Newcastle disease virus infection of chickens of different ages and different levels of immunity 总被引:2,自引:0,他引:2
Chickens of 7 weeks or 20 weeks of age were divided into three groups according to their antibody status (high, low, absent) and were infected with a velogenic viscerotropic Newcastle disease virus. To follow patterns of viral replication, birds were necropsied at regular intervals up to 22 days and organs were sampled from each bird. In non-immune birds, virus could be isolated from all organs examined. In birds with antibody, virus was most frequently isolated from the proventriculus, cecal tonsil, bursa, and brain. However, because no one organ could be recommended for all situations, all four should be sampled for field diagnosis. In immune birds, although clinical signs were either mild or absent, widespread virus replication occurred up to 19 days post-challenge. 相似文献
963.
P H McCarthy 《American journal of veterinary research》1990,51(4):611-618
The anatomy of each feature and structure of the laryngeal and adjacent regions, as perceived by palpation, is described for clinically normal standing horses. Visible skin contours produced by some of the superficial structures are also described. Concurrent dissection was performed on fresh cadavers to confirm initial findings. The procedure of systematic palpation in relation to clinical diagnosis and surgical procedure is discussed. 相似文献
964.
Repeated transplacental transmission of Neospora caninum in dogs 总被引:3,自引:0,他引:3
J P Dubey A Koestner R C Piper 《Journal of the American Veterinary Medical Association》1990,197(7):857-860
Four litters of German Shorthaired Pointers from one owner developed a toxoplasmosis-like illness. According to the records, 29 of 39 dogs had hind limb paralysis. Six dogs from 2 litters were necropsied and had generalized encephalomyelitis. Tachyzoites and tissue cysts of Neospora caninum were found in the brain and spinal cord of each dog. Lesions were found in the eyes, extraocular muscles, or both in all of the dogs, and N caninum was detected microscopically in the eyes (retina and choroid in 1 dog), extraocular muscles, or both in 5 of the 6 dogs. Ocular lesions consisted of focal retinitis, choroiditis, mild nonspecific iridocyclitis, and myositis of extraocular muscles. Organisms stained with anti-N caninum serum, but not with anti-Toxoplasma gondii serum in an immunohistochemical test, except in 1 dog. In one dog, aged thick-walled N caninum tissue cysts reacted mildly with anti-T gondii serum. 相似文献
965.
966.
967.
968.
969.
Comparative cell kinetics of avian growth plates 总被引:1,自引:0,他引:1
N F Kember J K Kirkwood P J Duignan D Godfrey D J Spratt 《Research in veterinary science》1990,49(3):283-288
New data on the cell kinetics of the cartilage growth plates in the chicken, budgerigar and rhea derived from studies with tritiated thymidine labelling are given. Quantitative histological measurements on growth plates from leg bones (tibiotarsus, tarsometatarsus and a phalangeal bone) in a further five species of birds are presented. Counts of flat cells and measurements of the average diameter of hypertrophic cells were made for each growth plate. These data are compared with values for the overall growth rates of the bones. The variation in sizes of hypertrophic cells was small and it is concluded that the largest factor in determining the growth rate of an avian bone is the size of the zone of flat cells. 相似文献
970.
W E Neville K L Richardson D J Williams B G Mullinix P R Utley 《Journal of animal science》1990,68(8):2188-2197
This study was conducted with Angus, Polled Hereford and Santa Gertrudis straightbred and crossbred cows. The subsequent cow breeding and calf performance of cows that were nonpregnant (NP) were compared with cows that were pregnant (PG) at the time calves were weaned. All NP cows had a calf the year previous to their being nonpregnant. They were diagnosed as physically sound with no detection (by rectal palpation) of an abnormal reproductive tract. The NP and PG cows were aged 4 to 9 yr. Also, the NP cows were compared with replacement females exposed to calve first as 2- and 3-yr-olds (H2 and H3, respectively), and with cows exposed for second calving as 3-yr-olds (C2). Cows were assigned within breed composition and age to sire breeding groups on pasture. Subsequent calving and weaning rates were similar for NP, PG and H2 cows, similar for H3 and H2 cows and lowest (P less than .05) for C2 cows. Calves from NP and H3 cows were born earlier (P less than .05) in the calving period than calves from PG and H2 cows, whereas calves from C2 cows were born later (P less than .05) than those from NP, PG and H3 cows. Calving difficulty was similar for NP, PG and C2 and greatest (P less than .05) for H2 cows. Calf 205-d weights were highest (P less than .05) for NP, similar for PG and H3 and lowest (P less than .05) for C2 and H2 cows. Calf weaning weight per cow exposed for breeding from NP cows was 13.8, 32.3, 55.2 and 1.0 kg higher than from PG, H2, C2 and H3 cows, respectively. Causes for cows being nonpregnant were reported. Also, calving patterns during 6 consecutive calving periods (6 yr) were evaluated. 相似文献