共查询到20条相似文献，搜索用时 62 毫秒
1.
营养物质对绵羊正常的生理机能是必需的,一切的营养物质对羊的繁殖总有着直接或间接的影响。在养羊生产上,常见的营养缺乏,如饲料能量的缺乏、蛋白质缺乏、维生素缺乏和矿物质缺乏等症均可引起繁殖障碍。另外,营养过剩也会使绵羊的生育力下降,以致绵羊出现营养性不育。1能量在养羊生产上,碳水化合物是动物日粮 相似文献
2.
3.
营养物质对羊正常的生理机能是必需的,所有的营养物质对羊的繁殖有着直接或间接的影响。临床上常见营养缺乏导致的繁殖障碍有饲料料量不足、蛋白质缺乏、维生素缺乏和矿物质缺乏等。同时,营养过剩也会使羊的生育力下降,导致营养性不育。1营养缺乏对羊在不同繁殖阶段的影响羊在不同的生理阶段对营养的需求不尽相同。羊在生长、发育及泌乳等阶段对营养物质都有各自独特的需要,尤其是处于繁殖阶段的母羊对营养要 相似文献
4.
5.
营养物质对羊正常的生理机能是必需的,所有的营养物质对羊的繁殖总有着直接或间接的影响。临床上常见的营养因素导致的繁殖障碍有饲料料量不足、蛋白质缺乏、维生素缺乏和矿物质缺乏等。同时,营养过剩也会使羊的生育力下降,导致营养性不育。在中国,大多数羊在牧区采用自由放牧的方式,在农区则是随机应用一些作物的副产品进行饲喂,采用平衡日粮养羊的极为少见,因此不可避免地存在着营养物质缺乏或不平衡,使其繁殖性能受到影响。营养缺乏可以通过各种作用而影响繁殖。从理论上来讲,一种营养物质的缺乏可以影响许多器官,而使繁殖功能非特异性降… 相似文献
6.
7.
8.
动物胃肠道微生物具有很强的代谢活性,对宿主的营养物质利用和生理代谢功能具有重要调控作用,可影响动物的生产性能和机体健康。为了适应胎儿的生长发育,妊娠期间母体的肠道菌群组成和代谢活性发生显著变化。笔者结合自己近年来的研究成果,对国内外母猪肠道微生态与繁殖生理方面取得的研究进展进行综述,以期为研发提高母猪繁殖性能的调控技术提供思路。 相似文献
9.
10.
微量元素对动物繁殖机能的影响 总被引：5，自引：0，他引：5
随着动物营养科学的发展,微量元素在动物体内的作用不断地被揭示。本文综述了锌、锰、碘、硒、铜,钼和钴等微量元素对动物繁殖机能的影响。锌对动物繁殖机能的影响一些学者(Chesters,1978;Hidirog-lou,1979;Apagar,1985)就动物缺锌对繁殖性能的影响进行了广泛的研究。动物体内200多种酶含有锌,其中一些酶与繁殖有关,但锌如何影响繁殖还知之甚少。锌是一些酶的必需成分或激活因子,而这些酶参与固醇类激素的合成。锌可能通过垂体间接影 相似文献
11.
12.
魏静 《四川畜牧兽医学院学报》2009,(4):28-32
在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。 相似文献
13.
14.
本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。 相似文献
15.
REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air. 相似文献
16.
17.
18.
Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF
Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo. 相似文献
19.
20.
以国际标准强毒Ｒ株人工感染非免疫产蛋鸡,定时扑杀,分别从鼻窦、眶下孔、气管、肺、气囊、卵巢和输卵管分离ＭＧ,并收集感染鸡所产蛋分离ＭＧ。结果表明,人工感染４８小时后上、下呼吸道及肺已被全面感染,９６小时气囊已被感染,１２０小时输卵管已能分离到ＭＧ,卵巢始终分离不到ＭＧ。人工感染鸡自１４４小时便能在其所产蛋中分离出ＭＧ。药物治疗能在７２小时内消除感染,油乳剂苗则需２４天后逐渐降低蛋内ＭＧ分离率,药物卵内注射、种蛋药浴、高温处理均能杀死卵内ＭＧ,但以研制的种蛋浸泡剂药浴效果为最好。 相似文献