首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   38篇
  免费   4篇
  1篇
综合类   8篇
畜牧兽医   30篇
植物保护   3篇
  2020年   3篇
  2019年   1篇
  2018年   1篇
  2017年   1篇
  2016年   2篇
  2015年   1篇
  2013年   2篇
  2010年   1篇
  2009年   4篇
  2008年   1篇
  2003年   1篇
  2002年   2篇
  2001年   2篇
  1999年   1篇
  1998年   4篇
  1997年   1篇
  1996年   2篇
  1995年   1篇
  1994年   2篇
  1993年   1篇
  1992年   2篇
  1991年   1篇
  1990年   1篇
  1989年   1篇
  1988年   1篇
  1987年   1篇
  1973年   1篇
排序方式: 共有42条查询结果,搜索用时 15 毫秒
1.
2.
Formation of a Reservoir of Sperm in the Oviduct   总被引:2,自引:0,他引:2  
A reservoir of sperm in the initial segment of the oviduct has been found in several species of domestic and laboratory mammals. Evidently, the reservoir serves to ensure successful fertilization by providing the appropriate number of sperm in the appropriate physiological state for fertilizing oocytes soon after they enter the oviduct. Recent evidence indicates that sperm are trapped in the reservoir by binding to specific carbohydrate moieties on the surface of the mucosal epithelium of the oviduct. A bovine seminal plasma protein has been identified that associates with sperm and confers on them the capacity to bind to the carbohydrate moiety.  相似文献   
3.
4.
ABSTRACT

Aims: To collect baseline data on the contact risk pathways and biosecurity practices of commercial poultry farms in New Zealand, investigate the relationship between the farm-level disease contact risks and biosecurity practices, and identify important poultry health concerns of producers.

Methods: A cross-sectional survey of all registered New Zealand commercial poultry operations was conducted in 2016 collecting information on farm demographics, biosecurity practices, and contact risk pathways. Survey responses were used to generate an unweighted subjective disease risk score based on eight risk criteria and a subjective biosecurity score based on the frequency with which producers reported implementing seven biosecurity measures. Producer opinions towards poultry health issues were also determined.

Results: Responses to the survey response were obtained from 120/414 (29.0%) producers, including 57/157 (36.3%) broiler, 33/169 (19.5%) layer, 24/55 (44%) breeder, and 6/32 (19%) other poultry production types. Median disease risk scores differed between production types (p?<?0.001) and were lowest for breeder enterprises. The greatest risk for layer and broiler enterprises was from the potential movement of employees between sheds, and for breeder enterprises was the on- and off-farm movement of goods and services. Median biosecurity scores also differed between production types (p?<?0.001), and were highest for breeder and broiler enterprises. Across all sectors there was no statistical correlation between biosecurity scores and disease risk scores. Producers showed a high level of concern over effectively managing biosecurity measures.

Conclusions: The uptake of biosecurity measures in the commercial poultry farms surveyed was highly variable, with some having very low scores despite significant potential disease contact risks. This may be related to the low prevalence or absence of many important infectious poultry diseases in New Zealand leading farmers to believe there is a limited need to maintain good biosecurity as well as farmer uncertainty around the efficacy of different biosecurity measures. Further research is needed to understand barriers towards biosecurity adoption including evaluating the cost-effectiveness of biosecurity interventions.  相似文献   
5.
6.
A 15‐year‐old, spayed, female poodle dog was presented for evaluation of a mass of tissue prolapsed from the vulva. The dog had been hysterectomized when it was 5 years old. A vaginal mass had been removed approximately 10 months before presentation. Haematological and serum biochemistry analyses demonstrated mild leucocytosis and glycaemia. A vaginal smear was predominantly made up of parabasal cells and intermediate cells with no neoplastic cells. Thoracal and abdominal radiographic findings were unremarkable. The ovaries could not be identified using abdominal ultrasonography. A midline exploratory laparotomy identified both ovaries that were surgically excised. The vaginal mass was also removed following an episiotomy procedure. Histopathological examination of the mass demonstrated that it was a neurofibroma. Both ovaries had cystic changes. Four months after the surgery, the owner reported that the dog was clinically normal. To the authors’ knowledge, this is the first reported case of a vaginal neurofibroma after an incomplete ovariohysterectomy in the dog.  相似文献   
7.
本研究分为2个试验,试验I评定赖氨酸发酵蛋白粉在生长猪上的营养价值;试验2研究赖氨酸发酵蛋白粉等蛋白质替代豆粕对生长肥育猪生长、胴体性状和肉品质的影响。试验1:选用(25.0±1.1)妇杜×长×大三元杂交猪12头进行消化代谢试验,随机分为2组,每组6个重复,每个重复1头猪,分别饲喂无氮日粮和以赖氨酸发酵蛋白粉作为唯一蛋白质源的试验日粮,预试期4d,正试期4d。试验2:选用(41.7±3.9)kg杜×长×大三元杂交猪100头进行饲养试验,随机分为4组,每组5个重复,每个重复5头猪。I组为对照组,饲喂基础日粮;Ⅱ、Ⅲ和Ⅳ组分别为饲喂赖氨酸发酵蛋白粉等蛋白质替代10%、25%、50%豆粕的试验日粮,体重达100kg左右结束。消化代谢试验结果表明:赖氨酸发酵蛋白粉消化能为12.85MJ·kg^-1,代谢能为11.80MJ·kg^-1。总氨基酸含量为47.38%,总氨基酸的回肠表观消化率、真消化率分别为66.95%和70.52%,赖氨酸和蛋氨酸的回肠表现消化率、真消化率分别为72.00%、75.14%和59.37%、64.52%。试验结果表明:与对照组相比,在生长期和全期,Ⅳ组平均日增重显著降低(P〈0.05),料重比显著升高(P〈0.05);在肥育期,Ⅳ组平均日采食量显著增加(P〈0.05),料重比显著升高(P〈0.05),生长期和肥育期,Ⅳ组氮消化率、氮生物学效价显著降低(P〈0.05)。Ⅳ组背膘厚显著增加(P〈0.05),眼肌面积和肌肉保水能力显著降低(P〈0.05)。由此得出,与豆粕相比,赖氨酸发酵蛋白粉的粗蛋白质和脂肪含量较高,非蛋白氮比例大,氨基酸消化率低。蛋白质替代10%和25%豆粕对40-100kg的生长肥育猪生产性能、胴体性状和肉品质均无影响,可作为饲粮中的新型蛋白质原料。  相似文献   
8.
Alterations in biochemical constituents of uterine fluid have been suggested for diagnosis of subclinical uterine infection in the bovine. This study was undertaken to investigate whether uterine fluid biomolecules could act as tool for diagnosis of subclinical endometritis in the buffalo. Uterine fluid samples from normal (n = 22) and subclinical endometritis (n = 18; diagnosed based on uterine cytology)‐affected buffaloes were subjected to biochemical analysis. Among the different biochemical constituents estimated, urea, urea N, cholesterol, total bilirubin and alkaline phosphatase (ALP) concentrations were significantly (p < 0.05) higher in uterine fluid obtained from subclinical endometritis‐affected buffaloes. The extent of difference between normal and subclinical endometritis‐affected buffaloes was highest in ALP (69%) followed by cholesterol (55%), bilirubin (48%), urea (30%) and urea N (30%) concentrations. Receiver operating characteristic (ROC) analysis indicated that the likelihood ratio (LR) was 3.63 for urea, indicating that buffaloes having less than the threshold concentration (47.5 mg/dl) of urea in their uterine fluid were at 3.6 times more risk to be affected with SE. The LRs for urea N, cholesterol, ALP and bilirubin were 2.33, 2.54, 2.12 and 1.65, respectively. It was concluded that ALP, urea, urea N and cholesterol concentrations in uterine fluid may serve as an aid for diagnosing subclinical endometritis in the buffalo.  相似文献   
9.
The aim of this research was to evaluate the efficacy of zinc gluconate associated with dimethyl sulphoxide (DMSO) for chemical neutering in canine males. Fifteen sexually mature male dogs were divided in two groups, named control and treated. An injection was administered to both testicles, at a concentration of 26.2 mg zinc gluconate per ml and 0.5% DMSO in the treated group (11 dogs). The control group was given injections of saline solution (four dogs). Clinical examination and blood collection for a haemogram were done both before and after drug injection. There were 12 spermograms performed to analyse sperm motility, sperm vigour, ejaculate volume, testicle size, pathology and sperm concentrations. Libido was also measured. An ultrasound examination and histopathology were performed at the end of the experiment. Dogs’ libido after chemical injection was reduced by over 50%. The spermogram analysis showed final mean results of 14.54% for sperm motility, 0.72 of sperm vigour and 37 150 per million spermatozoa per millilitre, values considered below the necessary levels at which fertilization can occur. Ultrasound and histopathology analyses of testicles for the treated group revealed more intense injuries when compared with the control group, with compromised testicular parenchyma and a decrease of germ cell number leading to total atrophy, indicating that the treatment reduced the fertilizing potential of male dogs, promoting a possible subfertile status.  相似文献   
10.
The effect of maternal antibody to the toxin of Corynebacterium pseudotuberculosis, produced by caseous lymphadenitis (CLA) in ewes or by vaccinating ewes before lambing, on the efficacy of vaccination against CLA in their lambs was examined. Lambs were allocated to treatments according to either the vaccination history of their dam or level of CLA toxin antibody of their dam. They were vaccinated twice using 2 different inoculation regimes and then artificially infected with CLA organisms. The number of lambs with CLA lesions was assessed at slaughter. In one experiment high levels of CLA toxin antibody activity in ewes were associated with decreased efficacy of CLA vaccination in their lambs, when lambs were vaccinated at 2 and 8 weeks or 8 and 14 weeks of age. In a second experiment the efficacy of lamb vaccination at 8 and 12 weeks, but not at 14 and 18 weeks of age, was decreased. In sheep flocks with a high prevalence of CLA, vaccinating lambs against CLA at less than 10 weeks of age may not produce optimum protection against CLA in lambs. There was no difference in infection rate between lambs from vaccinated and unvaccinated ewes. However, vaccination of lambs at 2 and 8 wks was less effective that vaccination at 8 and 14 weeks, probably due to reduced immunocompetence in young lambs. In sheep flocks where significant numbers of lambs receive their primary vaccination at less than 3 weeks of age vaccination programmes to control CLA in lambs may be less effective.  相似文献   
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