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   241篇
  免费   16篇
  国内免费   19篇
农学   2篇
基础科学   4篇
  10篇
综合类   55篇
水产渔业   1篇
畜牧兽医   204篇
  2024年   1篇
  2023年   4篇
  2022年   11篇
  2021年   32篇
  2020年   12篇
  2019年   21篇
  2018年   11篇
  2017年   23篇
  2016年   15篇
  2015年   9篇
  2014年   13篇
  2013年   10篇
  2012年   12篇
  2011年   17篇
  2010年   9篇
  2009年   6篇
  2008年   6篇
  2007年   11篇
  2006年   7篇
  2005年   7篇
  2004年   6篇
  2003年   5篇
  2002年   1篇
  2001年   6篇
  2000年   6篇
  1999年   2篇
  1998年   2篇
  1996年   2篇
  1993年   1篇
  1990年   1篇
  1987年   1篇
  1986年   1篇
  1984年   1篇
  1983年   1篇
  1979年   1篇
  1974年   1篇
  1973年   1篇
排序方式: 共有276条查询结果,搜索用时 125 毫秒
31.
智能饲喂器对哺乳母猪采食量体况和生产性能的影响   总被引:3,自引:2,他引:1  
为探究不同饲喂方式对哺乳母猪采食量、体况和生产性能的影响,满足哺乳母猪获得最大采食量并达到精准饲喂控制等需求,该文以哺乳母猪为试验对象,比较不同饲喂方式对哺乳母猪采食量、体况和生产性能的影响。试验共选用40只1胎母猪,随机分为3组:试验1组采用智能饲喂器饲喂(6次/d)、试验2组采用人工饲喂(6次/d)、对照组采用人工饲喂(3次/d)。结果表明,在试验环境条件下,哺乳8~21 d、人工饲喂3次/d的采食量(6.46 kg)显著高于智能饲喂6次/d(5.22 kg)(P0.05),2种饲喂方式在母猪的体质量变化、背膘变化、总产仔数、断奶后发情天数、仔猪日增体质量和用水量方面均无显著性差异(P0.05);哺乳母猪在采食过多时可能引起厌食进而降低后期的采食量,应按照饲喂参数逐步增加饲喂量饲喂;在现有设备投资和工资水平下,智能饲喂器正常使用4.5 a可取代1名优秀饲养员。研究结果可为今后智能化饲喂替代有经验人工饲喂、根据饲养条件选择饲喂方式提供参考。  相似文献   
32.
Sows mated in summer produce a greater proportion of born-light piglets (<1.1 kg) which contributes to increased carcass fatness in the progeny population. The reasons for the low birth weight of these piglets remain unclear, and there have been few successful mitigation strategies identified. We hypothesized that: 1) the low birth weight of progeny born to sows mated in summer may be associated with weight loss during the previous summer lactation; and 2) increasing early gestation feed allowance for the sows with high lactational weight loss in summer can help weight recovery and improve progeny birth weight. Sows were classified as having either low (av. 1%) or high (av. 7%) lactational weight loss in their summer lactation. All the sows with low lactational weight loss (LLStd) and half of the sows with high lactational weight loss received a standard gestation feeding regime (HLStd) (2.6 kg/d; day 0–30 gestation), whereas the rest of the sows with high lactational weight loss received a compensatory feed allowance (HLComp) (3.5 kg/d; day 0–30 gestation). A comparison of LLStd (n = 75) versus HLStd sows (n = 78) showed that this magnitude of weight loss over summer lactation did not affect the average piglet or litter birth weight, but such results may be influenced by the higher litter size (P = 0.030) observed in LLStd sows. A comparison of HLStd versus HLComp (n = 81) sows showed that the compensatory feeding increased (P = 0.021) weight gain of gestating sows by 6 kg, increased (P = 0.009) average piglet birth weight by 0.12 kg, tended to reduce (P = 0.054) the percentage of born-light piglets from 23.5% to 17.1% but reduced the litter size by 1.4 (P = 0.014). A subgroup of progeny stratified as born-light (0.8–1.1 kg) or -normal (1.3–1.7 kg) from each sow treatment were monitored for growth performance from weaning until 100 kg weight. The growth performance and carcass backfat of progeny were not affected by sow treatments. Born-light progeny had lower feed intake, lower growth rate, higher G:F, and higher carcass backfat than born-normal progeny (all P < 0.05). In summary, compensatory feeding from day 0 to 30 gestation in the sows with high weight loss during summer lactation reduced the percentage of born-light progeny at the cost of a lower litter size, which should improve growth rate and carcass leanness in the progeny population born to sows with high lactational weight loss.  相似文献   
33.
宫内发育迟缓(IUGR)降低仔猪存活率和生长性能,给养猪业带来严重经济损失.如何有效降低IUGR仔猪的出生,一直是行业关注的科学问题.胎盘是一个高度血管化的器官,其血管生成异常会阻碍氧气和营养物质的正常运输,导致胎盘无法正常向胎儿提供足够的营养物质,这可能是引起仔猪IUGR的重要因素.鉴于胎盘血管在胎猪生长过程中扮演的...  相似文献   
34.
妊娠后期随着胎儿生长速度和乳腺发育加快,母猪机体代谢强度逐渐增加,机体糖脂代谢失衡,出现代谢紊乱。能量占整个日粮成分的70%以上,选择适当的日粮能量来源以调节糖脂代谢的平衡是提高母猪繁殖效率的有效方法。淀粉与油脂作为母猪日粮主要能量来源,均可显著影响后备母猪的初情期启动或经产母猪的繁殖性能,但以母猪本身的糖脂代谢特征为出发点,评述不同来源与水平的淀粉或油脂对母猪繁殖性能的影响鲜有总结报道。文章首先综述了母猪妊娠期糖脂代谢特点和代谢机制,简述了妊娠期代谢紊乱对母猪繁殖性能的不良影响,介绍了淀粉与油脂在母体的吸收及代谢特点,对比分析了不同水平与来源的淀粉和油脂对母猪产仔性能和泌乳性能的影响。最后,为最大化提高猪场经济效益,根据实际生产目的,总结了选择合适能量来源的依据。该综述旨在选择日粮适宜水平和来源的淀粉和油脂以期为提高母猪繁殖效率提供数据支持和理论指导。  相似文献   
35.
This study investigated the litter performance of lactating sows fed nutrient‐dense diets with or without dextrose at farrowing to weaning, during the summer with an average room temperature of 28.4°C. A total of 60 (13 first parity, 13 second parity, 19 third parity, and 15 forth parity) cross‐bred sows were assigned to three treatments. The three treatments were: standard diet (ST), high nutrient diet (HN; ST + 3% higher energy and 18.0% protein), and high nutrient diet plus dextrose (HND; 3% higher energy, 18.0% protein, and 5% dextrose). BW loss was reduced in the HND sows compared with the ST sows during lactation. The HN and HND sows had a higher piglet and litter weight at weaning. Also, the HND sows had the highest post‐prandial insulin levels at weaning and the shortest weaning‐to‐service interval (WSI). Serum LH was higher in the HND sows than the ST sows. The milk fat level was higher in the HND sows compared with the ST sows, but similar to the HN sows. In conclusion, these results suggest that it is possible to increase the blood insulin response by supplementing dextrose to a high nutrient diet, thus, improving WSI interval and litter growth during heat stress.  相似文献   
36.
为研究复合有机铁对母猪繁殖性能、血液理化指标及抗氧化能力的影响,试验选用体重接近、胎次接近、预产期一致的健康“长×白”二元杂母猪30头,随机分为3组,每组10个重复,每个重复1头母猪,3个处理组分别在基础日粮中补充硫酸亚铁、甘氨酸亚铁、复合有机铁。结果显示:较硫酸亚铁组,复合有机铁组产程缩短23.57%、胎产健仔数增加14.00%、初生窝重增加14.14%(P < 0.05);母猪血红蛋白含量、红细胞数和红细胞压积分别提高19.88%、10.53%、8.33%(P < 0.05);母猪抗氧化酶活性和机体抗氧化能力提高47.33%(P < 0.05),丙二醛含量降低37.05%(P < 0.05)。综上所述,母猪日粮中额外补充复合有机铁源能提高母猪繁殖性能,改善血液理化指标,增强母猪抗氧化能力。  相似文献   
37.
When sows and their litters are kept outdoors, much of the responsibility for the litter is shifted from the herdsman to the sow compared to when the sows are kept indoors. Therefore, the maternal ability, including maternal behaviour, is believed to be important in outdoor piglet production. The aim of this study was to describe maternal traits in conventionally bred first-parity sows kept outdoors. Nursing behaviour, sow activity, sow body reserves, litter size and piglet growth were studied in 40 first-parity sows during a seven week long lactation. The sows were kept in groups outdoors. Sow activity (lying down or active) and nursing behaviour (nursing frequency, nursing duration and nursing terminator) were recorded on videotapes at four days post partum (pp) and directly observed at four and six weeks pp. Cross suckling was observed at four and six weeks pp. Sows were weighed and measured for backfat depth five days before farrowing, two weeks pp and at weaning seven weeks pp. Piglets were weighed at four days pp, at two weeks pp and at weaning. We concluded that sow nursing behaviour and activity are individual characteristics repeatable within sows' late lactation. Less active sows are more available for suckling. Light and thin sows have an earlier and more progressed weaning process than heavier, fatter sows. A significant positive relation was found between sow appetite in early lactation and piglet growth until weaning. Sow nursing behaviour is not important for piglet growth when sows and piglets are held in groups, piglets have access to sow feed and piglets are weaned as late as at seven weeks of age.  相似文献   
38.
This study aimed to provide new insights into the epidemiology of Salmonella in pig production, focusing on potential shedding patterns in breeding pigs throughout a full production cycle and the risk of transmission of infection from the sow to her offspring. A longitudinal study was conducted on five farrow‐to‐finish commercial pig farms. In each herd, shedding of Salmonella in faeces was monitored in breeders through service, gestation and lactation. Swabs of the farrowing room floor and pools of faeces from piglets were collected on two occasions during lactation. Environmental pen swabs were also taken in the weaning and finisher houses. Salmonella isolates were serotyped, tested for antimicrobial resistance (AMR) and typed by Multiple‐Locus Variable number tandem repeat Analysis (MLVA). Shedding by breeding pigs was low in all stages of the production cycle; 5% of sows shed at service, the production stage with highest risk of shedding (p < .01), 1.6% shed during gestation and 2.5% after farrowing. Salmonella was detected in 4% of piglet faecal pools in the second week post‐farrowing and 5% in the fourth week. Serotyping and AMR profiles of Salmonella isolates revealed that strains in sows and gilts were mostly different from strains isolated in weaner and finisher facilities. MLVA typing confirmed that the source of infection in piglets was in most instances the contaminated environment rather than their dam. Based on the typing results, it appears that sows do not pose a major risk in the maintenance and transmission of Salmonella to their progeny but instead the contaminated pen environment is more significant in the perpetuation of the organism on farm.  相似文献   
39.
开展以沼液浇灌的“闽牧6号”杂交狼尾草(Pennisetum americarum×P.purpureum cv.Minmu 6)打浆不同比例饲喂怀孕早中期母猪(0~80 d)效果研究,试验设4个饲喂量处理,处理1(CK)~处理4,妊娠早中期分别饲喂打浆鲜草0、2、4、6 kg/(头·d),牧草以折合成干物质等量替代配合饲料。结果表明,4个处理的母猪窝产仔数分别为13.42、10.60、13.64和11.50头,窝活仔数分别为12.42、10.30、12.73和9.92头,饲喂2和4 kg/(头·d)打浆鲜草在活仔数方面与对照差异不显著,而饲喂6 kg/(头·d)打浆鲜草则显著低于不饲喂鲜(P<0.05)。饲喂牧草的处理仔猪初生体质量、健仔率都比对照得到不同程度的提高,试验结果还表明,怀孕早中期母猪通过饲喂2~4 kg/(头·d)狼尾草草浆来补充纤维来源,可提高母猪的生产性能和仔猪品质,尤其以饲喂4 kg/(头·d)打浆鲜草,饲粮粗纤维含量为8.24%~9.41%,效果最佳。  相似文献   
40.
The effects of feeding glucose during the 5 days before parturition on litter performance and on glucose concentration in sows were studied. At day 100 of gestation, 130 multiparous sows were assigned to the treatments. Late gestating sows were fed 0 g, 150 g, 250 g, 350 g and 450 g of glucose a day, respectively. During lactation, all sows were given free access to the same lactation diet (without glucose). One day before parturition, blood samples were collected from 30 sows (6 sows per treatment) at 10 before and 20, 40, 60 and 80 min after the meal. The supply of additional dietary glucose increased piglet birth weight ( P  < 0.05). Feed intake in week 1 and week 1–4 of lactation was greatest in sows fed the 0% glucose diet, least by sows fed the 18% glucose diet, and intermediate by sows fed the 6, 10, 14% glucose diets ( P  < 0.05). Basal glucose concentration and time of maximum glucose concentration after glucose intake were not affected by dietary treatment in the last 5 days of gestation. The sows fed the 14 and 18% glucose diets had greater maximum increase in glucose concentration than sows fed diet without glucose ( P  < 0.05). In conclusion, feeding glucose to sows during 5 days before parturition increased birth weight of live-born piglet and decreased sows feed intake during lactation, but did not affect the performance of sows and piglets.  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