Eastern equine encephalitis in a flock of emus (Dromaius novaehollandiae).     

T N Tully  S M Shane  R P Poston  J J England  C C Vice  D Y Cho  B Panigrahy 《Avian diseases》1992,36(3):808-812

Eastern equine encephalitis (EEE) was diagnosed in a flock of emus in southeastern Louisiana. The outbreak involved juvenile and adult breeders ranging in age from 20 to 36 months, with an attack rate of 76% and a case fatality rate of 87%. The diagnosis was confirmed by isolation and characterization of the viral agent, and by detection of EEE antibody in two recovered emus. High mortality was preceded by marked depression, hemorrhagic diarrhea, and emesis of blood-stained ingesta. On postmortem examination, hemorrhagic enteritis and multiple petechia of viscera were observed. Microscopic changes included severe necrosis of hepatocytes, intestinal mucosa, and necrotizing vasculitis of the spleen and lamina propria of the intestine. No nervous system lesions were observed. This outbreak occurred concurrently with EEE in horses and was attributed to unseasonably heavy rainfall with an abundance of arthropod vectors and proximity to free-living reservoir host species.  相似文献   

Skin and plumage changes in domestic birds. II. Plumage changes]     

T Bartels  W Meyer  K Neurand 《Tier?rztliche Praxis》1992,20(3):275-281

The study describes plumage modifications and specific feather malformations, as related to the domestication process of different poultry species. The modifications include naked necks, leg feathering, frizzle feathering, silky feathering, fat quills, and feather abnormalities caused by behavioural hypertrophies. Most of these plumage modifications correspond to the breed standard for exhibition poultry fancy. However, they impair the normal function of these animals. The negative influences comprise disorders in social behaviour, loss of typical plumage functions and disabilities of normal mobility, as well as genetic defects and pathogenic predispositions.  相似文献   

Behavioral and physiological effects of freeze or hot-iron branding on crossbred cattle.     

D C Lay  T H Friend  R D Randel  C L Bowers  K K Grissom  O C Jenkins 《Journal of animal science》1992,70(2):330-336

Twenty-seven crossbred calves (1/2 Simmental, 1/4 Hereford, 1/4 Brahman) averaging 257 +/- 11 d of age were either hot-iron-branded (H), freeze-branded (F), or sham-branded (S). Calves were blocked for temperament, weight, and sex and were randomly assigned to day and order in which treatments were applied. To reduce stress from handling at treatment time, each calf was herded through the squeeze chute daily for 5 d before the experiment. Jugular cannulas were inserted in each calf 1 d before application of treatment. Blood samples and heart rate measures were obtained at -5, -3, 0, .5, 1, 3, 5, 10, 15, and 20 min after application of the treatments. Mean concentrations of plasma epinephrine (EPI) were higher for H calves at time .5 min than for either S or F calves (P = .10). To account for individual differences, prebranding heart rates and hormone concentrations were subtracted from subsequent samples and were also used to calculate a proportion for each subsequent sample. Analyses of subtracted values found that EPI concentrations were greater for H calves than for either S or F calves (P = .007) at .5 min postbranding. No other differences were found for the subtracted analyses. Analyses of proportion data also revealed that H calves had greater EPI than did either S or F calves (P = .027) at .5 min postbranding. Only three animals vocalized during branding, one H calf and two F calves. Despite the 5-d acclimation period, handling and restraint elevated plasma cortisol concentrations and heart rate.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

Identification of the surface components of Trypanosoma evansi.     

U E Uche  C A Ross  T W Jones 《Research in veterinary science》1992,53(2):252-253

125I-labelling was used to characterise the surface components of five stocks of Trypanosoma evansi. Two components of 67 and 60.5 kD were labelled in two of the stocks, a single 60.5 kD component in two other stocks and no components in the remaining stock. These differences are probably related to the labelling method and biochemical differences between the stocks.  相似文献   

Effect of initial restraint, weaning, and transport stress on baseline and ACTH-stimulated cortisol responses in beef calves of different genotypes.     

M T Zavy  P E Juniewicz  W A Phillips  D L VonTungeln 《American journal of veterinary research》1992,53(4):551-557

The productivity and well-being of animals can be substantially affected by stress. This is particularly true in the case of beef calves that are subjected to a multitude of stressors over a short period during the first year of life. Perhaps the most often studied stress-responsive variable has been blood corticosteroid concentrations. Factors such as age, gender, genetics, and degree of prior experience, can influence how an animal perceives and responds to a given stressor. Few studies have tried to control these variables, and accordingly, many conflicting results have been published regarding the impact of various stressors on cortisol response. We measured baseline plasma cortisol concentration over a 44-day study in Bos indicus and Bos taurus calves. Plasma cortisol values in Bos indicus calves were higher (32.60 +/- 0.66 ng/ml) than values in calves of Bos taurus (25.81 +/- 0.76) breeding. A precipitous decrease in cortisol concentration was observed 7 days after transport stress in all calves. Baseline cortisol concentration did not provide any indication of the intensity of the various stressors. However, significant differences were readily observed after ACTH administration. On the basis of cortisol secretion, stresses of transport and weaning were similar and were the most stressful to calves, regardless of genotype.  相似文献   

分离群体中常染色体上标记基因的数量遗传方差——Ⅰ.含有一个数量性状位点(QTL)时的计算方法     

张智英 《中国牛业科学》1994,(1)

应用常染色体上的标记基因研究能够加快数量性状的遗传进展。亲代由标记基因遗传给后代的加性遗传方差值可以用来测定标记基因这种效益。分别在个体水平上以及在复合连续平衡的分离群体水平上建立了标记基因加性遗传方差值的理论方程。这些方程包括与标记基因连锁的数量性状位点数、这些数量性状位点的效应值以及与标记基因有关的重组率。并就分离群体中标记基因加性遗传方差的期望值进行了推导。在分离群体的系谱选择方案中,常染色体上遗传方差中绝大部分与位于该染色体上的标记基因相关。对于牛的一个平均长度染色体来讲,这部分值大约是该染色体孟德尔分离方差值的40% 。标记基因的位置效应和干扰因素对这一期望值的影响是很小的,而染色体的长度对期望方差值影响很大。如果标记基因缺乏多态型以及染色体替代效应估计偏差会大大降低MAS的选择效果。常染色体上标记基因遗传方差期望值的大小表明:即使当标记基因处在一个非活动位点,在分离群体中,仍有较大的染色体替代效应存在。  相似文献   

Efficacy of abamectin against natural infections of gastrointestinal nematodes and lungworm of cattle with special emphasis on inhibited, early fourth stage larvae of Ostertagia ostertagi.     

J C Williams  A F Loyacano  C Nault  R T Ramsey  R E Plue 《Veterinary parasitology》1992,41(1-2):77-84

The anthelmintic efficacy of abamectin (avermectin B1) was evaluated against gastrointestinal nematodes, including Ostertagia ostertagi inhibited larvae and lungworm, in yearling crossbred beef heifers during late spring. The calves were grazed on contaminated pasture for 10 weeks and then held under conditions free of nematode infection for 3 weeks prior to allotment and treatment on 5 June. Thirteen calves were randomly assigned to two groups of six by restricted randomization on body weights; the extra lightest calf was assigned to the non-treated control group. Group 1 calves were treated with abamectin at 200 micrograms kg-1 body weight by s.c. injection and Group 2 calves were not treated; all were killed at 14 days after treatment. Ostertagia ostertagi was present in all controls; arithmetic mean numbers of adults, developing fourth stage larvae (L4) and inhibited EL4 were 7683, 605 and 36,102, respectively. Other nematode genera present in controls in sufficient numbers for the experiment were Haemonchus placei adults, Trichostrongylus axei adults, Cooperia spp. adults, Oesophagostomum radiatum adults, Bunostomum phlebotomum adults, Dictyocaulus viviparus adults and E5 (immature adults). Abamectin was highly effective (consistently greater than 99% efficacy and P less than 0.05) in removing all nematodes present in treated calves as represented in non-treated controls, including the primary target of Ostertagia ostertagi inhibited EL4. The lowest efficacy was 93.8%, against D. viviparus E5.  相似文献   

Cardiopathological observation on a case of persistent ventricular tachycardia in a pony mare.     

N Machida  T Nakamura  K Kiryu  S Haramaki  K Too 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》1992,54(6):1213-1216

A 20-year-old pony mare with persistent ventricular tachycardia (VT) was examined cardiopathologically. At necropsy, the heart was enlarged and rounded with both ventricular dilatation. In a longitudinal section of the ventricular septum, a large grayish white patchy lesion (5 x 25 mm) was detected in the relatively higher portion. Microscopically, the lesion was extensive myocardial fibrosis located in the vicinity of the proximal part of the left bundle branch. Partially the fibrotic lesion was in contact with the branch. Such a lesion might play an important role in creating a suitable background for the development of VT via automaticity or reentry mechanism.  相似文献   

Effect of dietary vitamin A on resistance to experimental Escherichia coli infection of uterus in rats     

T Inaba  A Inoue  Y Nakano  J Mori 《Nippon juigaku zasshi. The Japanese journal of veterinary science》1989,51(6):1247-1249

  相似文献   

Prevalence of Cryptosporidium sp in equids in Louisiana   总被引：3，自引：0，他引：3  

S U Coleman  T R Klei  D D French  M R Chapman  R E Corstvet 《American journal of veterinary research》1989,50(4):575-577

In 1985, 22 pony foals reared in a helminth-free environment were tested daily for oocysts of Cryptosporidium sp by use of fecal flotation. Oocysts were found in all foals. Oocysts were first observed in feces collected from foals 9 to 28 days after birth. The mean period of oocyst shedding was 10 days and ranged from 2 to 18 days in individual foals. Diarrhea was observed in 14 of 22 (64%) foals and began before the period of oocyst shedding. Fecal samples also were examined for other infective agents. Salmonella poona was isolated from 1 foal that did not have diarrhea, and coronavirus particles were observed in the feces of 2 foals with diarrhea. Cryptosporidium sp oocysts also were observed in feces of 2 of 17 Thoroughbred foals, 3 of 14 Quarter Horse foals, and 3 of 26 pony foals reared on pastures with their dams. Samples from pasture-reared foals were collected at irregular intervals. Of the 11 Cryptosporidium-positive fecal samples collected from pastured foals, 2 were from foals with diarrhea. A similar survey was conducted during the 1986 foaling season, using the same procedures. Examination of 300 samples from 58 Quarter Horse, Arabian, and pony foals did not detect oocysts. Daily examination of feces from 10 pony foals reared under helminth-free conditions for 30 days also failed to detect Cryptosporidium oocysts.  相似文献