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   82篇
  免费   9篇
  1篇
综合类   1篇
畜牧兽医   85篇
植物保护   4篇
  2019年   3篇
  2018年   5篇
  2017年   1篇
  2016年   2篇
  2015年   4篇
  2014年   2篇
  2013年   5篇
  2012年   4篇
  2011年   8篇
  2010年   1篇
  2009年   5篇
  2008年   5篇
  2007年   6篇
  2006年   3篇
  2005年   3篇
  2004年   2篇
  2003年   3篇
  2002年   1篇
  2001年   6篇
  2000年   4篇
  1999年   1篇
  1998年   2篇
  1997年   1篇
  1996年   2篇
  1995年   3篇
  1993年   2篇
  1992年   2篇
  1991年   1篇
  1990年   3篇
  1988年   1篇
排序方式: 共有91条查询结果,搜索用时 140 毫秒
1.
2.
3.
AIMS: To determine the suitability of diets containing either approximately 85% fodder beet (Beta vulgaris L.) with barley straw or 65% fodder beet with pasture silage when fed to non-lactating dairy cows, by measuring intakes, digestibility, rumen function including microbial growth, and N excretion.

METHODS: Holstein-Friesian cows fitted with permanent rumen fistulae were fed either 65% fodder beet with pasture silage (Silage; n=8) or 85% fodder beet with barley (Hordeum vulgare L.) straw (Straw; n=8) in an indoor facility over a 9-day period, for measurement of intakes, digestibility, rumen function and urine production. The cows were adapted to the diets over 2 weeks before the indoor measurements. Feed was available for about 6 hours/day, as practiced commercially for wintering non-lactating cows.

RESULTS: Five cows fed the Straw diet had to be removed from the trial because of acute acidosis; four on Day 1 of the measurement period and one on Day 7. One cow allocated to the Silage diet refused to eat fodder beet bulbs and was also removed from the trial. Two cows fed the Silage diet were also treated for acidosis. DM intakes were lower with the Straw than Silage diets (6.4 (SE 0.4) vs. 8.3 (SE 0.5) kg/day) and organic matter (OM) digestibility was lower with the Straw than Silage diets (77 (SE 1) vs. 83 (SE 1) g/100g). The N content of the two diets was 1.14 and 1.75?g/100?g DM and there was a net loss of N by cows fed the Straw diet (?22.7 (SE 7) g/day). Rumen microbial N production was much lower in cows fed the Straw than the Silage diet (6.6 (SE 1.3) vs. 15.8 (SE 0.7) g microbial N/kg digestible OM intake). Concentrations of ammonia in rumen liquid collected on Days 5–6 were below detection limits (<0.1?mmol/L) in 36/48 (75%) samples collected from cows fed the Straw diet and in 27/48 (56%) cows fed the Silage diet. Mean urinary N excretion was lower in cows fed the Straw than the Silage diet (52.0 (SE 5.8) vs. 87.7 (SE 5.9) g/day).

CONCLUSION AND CLINICAL RELEVENCE: An over-wintering diet for dry cows comprising about 65% fodder beet with 35% pasture silage provided adequate nutrition, although there was some risk of acidosis. In contrast, the diet containing about 85% fodder beet with barley straw resulted in lower DM intakes, poor rumen function, negative N balance so that both nutrition and welfare were compromised.  相似文献   
4.
The objectives of the work were to study the features of experimentally induced canine mastitis and to present hypotheses regarding the pathogenesis of the disease. The right caudal abdominal mammary gland of six bitches was inoculated on day 8 after whelping with Staphylococcus intermedius to induce mastitis; adjacent mammary glands were used as controls. Clinical examination, bacteriological and cytological (whiteside test, Giemsa) examination of mammary secretion, as well as haematological tests were performed from 5 days before until 34 days after challenge. Mastectomy was sequentially performed 1, 2, 4, 18, 26 and 34 days after challenge in each of the bitches, in order to carry out a pathological examination of mammary glands. All animals developed clinical mastitis: challenged glands became painful, hot, enlarged and oedematous; secretion was brownish, purulent, with flakes or clots, subsequently becoming yellowish and thick. Staphylococci were isolated from all inoculated glands (up to 22 days). WST was positive in 41/46 samples from inoculated glands and 66/138 samples from control glands; neutrophils predominated during the acute stage. Blood leukocyte counts increased, whilst platelet counts decreased. Gross pathological findings initially included congestion, purulent discharge and subcutaneous oedema; then abscesses, brownish areas and size decrease were seen. Salient histopathological features were initially neutrophilic infiltration, haemorrhages, destruction of mammary epithelial cells and alveoli, and then infiltration by lymphocytes, shrunken alveoli, loss of glandular architecture and fibrous tissue proliferation. We conclude that in bitches, intrammamary inoculation of Staphylococcus intermedius can induce clinical mastitis, followed by subclinical disease. The disorder is characterized by bacterial isolation and leukocyte influx in challenged glands, by leukocyte presence in adjacent mammary glands, by increased blood leukocyte counts and by destruction of mammary parenchyma.  相似文献   
5.
We describe the features of 13 cases of teat disorders in ewes, as follows: lengthy teats (one case), papilloma infection (two), staphylococcal dermatitis (one), nodules and abscesses (two), teat bites (three), stenosis (one), orf (two), compressed teat (one). Mannheimia haemolytica, Staphylococcus epidermidis, Staphylococcus simulans or Staphylococcus aureus were isolated from samples. Sub-epithelial leucocytic infiltration at the teat duct-teat cistern border, but not lymphoid nodules, was the salient histological finding in the teat. Leucocytic infiltration and destruction of parenchyma were evident in the mammary gland. The results provide field evidence suggesting that teat lesions predispose ewes to mastitis.  相似文献   
6.
In a field investigation of 47 flocks in south Greece, a clinical examination for fertility evaluation was done on 293 rams. In each ram, a general-health examination, examination of the genital organs and libido evaluation were carried out. In 143 (49%) of the 293 rams examined, at least one abnormality was recorded. The median within-flock prevalence risk (PR) of at least one abnormality was 58.0%, that of general-health abnormalities was 33%, that of genital abnormalities was 20% and that of libido abnormalities 14%. The principal abnormalities observed during the general-health examination were interdigital dermatitis, injuries of the sole, blowfly myiasis and brisket sores. The principal abnormalities observed during the examination of the genitalia were testicular hypoplasia, nodules into the testicular parenchyma, ulcerative lesions characteristic of orf in the prepuce and blowfly myiasis on the preputial orifice. The principal abnormalities observed during the evaluation of libido were incomplete erection and inability to mount the ewe. A statistically significant (P<0.05) positive association was recorded between: ram:ewe ratio and general-health abnormalities PR; general-health abnormalities PR and at least one abnormality PR; genital abnormalities PR and libido abnormalities PR; genital abnormalities PR and at least one abnormality PR; lambing percentage and total lambs born per ewe. A statistically significant (P<0.05) negative association was recorded between: ram age and general-health abnormalities PR; ram age and any abnormality PR; general-health abnormalities PR and lambing percentage.  相似文献   
7.
8.
In bitches, the length of gestation is highly variable when measured from the day of mating, thus prediction of parturition may be greatly inaccurate when determined from this point. The ability to precisely predict the duration of pregnancy is of practical importance for managing parturition or planning caesarean section and this review analyses the methods that can be used to accurately forecast the day of parturition. At the time of breeding, determination of the luteinizing hormone surge and the initial rise in progesterone provide reliable information on gestational length of the bitch, but when pregnancy is ascertained, ultrasonography is the most useful tool to predict the delivery day. In fact, by ultrasonographic measurements of the extra-foetal and foetal structures an accurate prediction can be made both in early and late pregnancy.  相似文献   
9.
The aim of this study was to examine the effect of varying intracellular reactive oxygen species (ROS) levels during oocyte in vitro maturation with enzymatic ROS production systems (xanthine + xanthine oxidase or xanthine + xanthine oxidase + catalase), scavenger systems (catalase or superoxide dismutase + catalase) or cysteine on porcine oocyte maturation. Oocyte ROS levels showed an increase when H2O2 or O2? production systems were added to the culture medium (p < 0.05). On the other hand, the presence of ROS scavengers in the maturation medium did not modify oocyte ROS levels compared with the control after 48 h of maturation, but the addition of cysteine induced a decrease in oocyte ROS levels (p < 0.05). The ROS production systems used in this work did not modified the percentage of oocyte nuclear maturation, but increased the decondensation of sperm head (p < 0.05) and decreased the pronuclear formation (p < 0.05). In turn, the addition of O2? and H2O2 scavenging systems during in vitro maturation did not modify the percentage of oocytes reaching metaphase II nor the oocytes with decondensed sperm head or pronuclei after fertilization. However, both parameters increased in the presence of cysteine (p < 0.05). The exogenous generation of O2? and H2O2 during oocyte in vitro maturation would not affect nuclear maturation or later sperm penetration, but most of the spermatozoa cannot progress to form the pronuclei after fusion with the oocyte. The decrease in endogenous ROS levels by the addition of cysteine would improve pronuclear formation after sperm penetration.  相似文献   
10.
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