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光照对家禽来讲是很重要的环境条件之一。实践表明,光照的时间与强度、光线的颜色与波长、光照刺激的起始时间、黑暗期的间断等都会在家禽生长发育、繁殖等方面产生一定反应,从而使家禽体成熟、增重、性成熟。开产时间、产蛋率、精液的产生与交配活动等受到影响。人工光照的广泛应用,克服了家禽繁殖生理机能季节性限制,使其遗传潜力能最大限度地发挥出来,增加了养禽的经济效益。适宜的光照对家禽的活动、新陈代谢、生长发育和生产力都有重要影响。l光照对家禽作用机制1.l一般认为禽类有两个光感受器,一个为视网膜感受器,另一个为视… 相似文献
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光照作为家禽生长发育关键的环境因子之一。光色、光照时间、光照强度和制度都能对家禽生长发育、繁殖性能以及免疫机能产生一定的影响,合理有效的光照可以最大限度地发挥出家禽的遗传潜力。 相似文献
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光照作为家禽生长发育关键的环境因子之一。光色、光照时间、光照强度和制度都能对家禽生长发育、繁殖性能以及免疫机能产生一定的影响,合理有效的光照可以最大限度地发挥出家禽的遗传潜力。 相似文献
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余德元 《畜牧兽医科技信息》2009,(6):86-86
光照是家禽生长发育过程中很重要的环境条件之一.实践证明,光照的时间与强度、光线的颜色与波长、光照刺激的起始时间、黑暗期的间断等都会在家禽生长发育、繁殖等方面产生一定反应,从而使家禽体成熟、增重、性成熟、开产时间、产蛋率、精液的产生与交配活动等受到影响. 相似文献
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光照对家禽的影响和光照控制 总被引:1,自引:0,他引:1
光照是家禽不可缺少的环境条件之一。实践表明,光照的时间与强度、光线的颜色和波长、光用刺激的起始时间,黑暗期的间断等都会在家禽生长发育、警在等方而激起一定反应,影响家禽性成熟、体成熟、产蛋率、产蛋时间、增重率、精液的产生与交配活动等。人工光照的广泛应用,克服了自然日照的季节性局限,能够创造符合于内作繁殖生理机能所需要的昼长,母禽可在任何季节开始其产蛋期,使其遗传潜力能最大限度地发挥出来,这就大大增加了禽蛋的生产量。适宜的光照对家禽的活动、物质代谢、生长发育和生产力都有重要作用,所以说光照同饲料、饮… 相似文献
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Evidence for the non-involvement of the uterus in the lifespan of the corpus luteum in the cyclic dog 总被引:1,自引:0,他引:1
Progesterone levels in peripheral blood of dogs were analysed during the cycle in which hysterectomy (n = 5) or sham surgery (n = 3) was performed as well as during the cycle of dogs (n = 5) hysterectomized at least one year prior to this study; the data were compared with the findings in control dogs (n = 3). The averages of the duration of the luteal period observed in the three experimental groups were not significantly different from those of control dogs. Immediately after surgery, the progesterone level decreased from 25 to 50% of the presurgical level, but returned to presurgical level in about four days. Prolactin levels were elevated for about 30 h after surgery. Nevertheless, the averages of the mean prolactin levels for each animal during the luteal period of the experimental groups were not significantly different from those of control dogs. It is concluded that in the dog, the uterus is not involved in the lifespan of the cyclic corpus luteum. 相似文献
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Meschan EM Peham C Schobesberger H Licka TF 《Veterinary journal (London, England : 1997)》2007,173(3):578-584
As there is no statistical evidence that saddle fit influences the load exerted on a horse's back, this study was performed to assess the hypothesis that the width of the tree significantly alters the pressure distribution on the back beneath the saddle. Nineteen sound horses were ridden at walk and trot on a treadmill with three saddles differing only in tree width. Kinetic data were recorded by a sensor mat. A minimum of 14 motion cycles were used in each trial. The saddles were classified into four groups depending on fit. For each horse, the saddle with the lowest overall force (LOF) was determined. Saddles were classified as "too-narrow" if they were one size (2 cm) narrower than the LOF saddle, and "too-wide" if they were one size (2 cm) wider than the LOF saddle. Saddles two sizes wider than LOF saddles were classified as "very-wide". In the group of narrow saddles, the pressure in the caudal third (walk 0.63 N/cm(2)+/-0.10; trot 1.08 N/cm(2)+/-0.26) was significantly higher compared to the LOF saddles (walk 0.50 N/cm(2)+/-0.09; trot 0.86 N/cm(2)+/-0.28). In the middle transversal third, the pressure of the wide saddles (walk 0.73 N/cm(2)+/-0.06; trot 1.52 N/cm(2)+/-0.19) and very-wide saddles (walk 0.77 N/cm(2)+/-0.06; trot 1.57 N/cm(2)+/-0.19) was significantly higher compared to LOF saddles (walk 0.65 N/cm(2)+/-0.10/ 0.63 N/cm(2)+/-0.11; trot 1.33 N/cm(2)+/-0.22/1.27 N/cm(2)+/-0.20). This study demonstrates that the load under poorly fitting saddles is distributed over a smaller area than under properly fitting saddles, leading to potentially harmful pressures peaks. 相似文献
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嗅源是军犬嗅觉作业训练的依据.军犬鉴别中嗅源能力的培养在整个鉴别训练中占有重要地位,关系到鉴别训练的成败和鉴别能力的提高.所以,军犬在嗅认嗅源时必须按照训犬员的指令充分、细致地感受嗅源气味,并且对嗅源气味产生兴奋反应.如何培养军犬充分嗅认嗅源以及及时解决嗅认过程中出现的问题,成为我们进行鉴别训练的关键.…… 相似文献
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Observations on the Pathology of the Spleen of the Cat 总被引:1,自引:0,他引:1
Abstract— Lesions were found in the spleen of four of sixty-three cats examined post mortem in the department, and comprised two examples of lymphosarcoma, one of chronic fibrinous peritonitis and one of subcapsular haematoma. Abnormalities were found in two cat spleens received from veterinary surgeons in general practice. In one cat the abnormalities were an haemangiosarcoma with secondary deposits in the liver and in the other extensive mast cell infiltration. In addition lesions were detected in the spleen of three of eighty-seven cats examined post mortem in general practice. The lesions were: multiple secondary deposits of adenocarcinoma from a primary tumour of the mammary gland, a ruptured spleen and a foreign body below the splenic capsule. Résumé— L'examen microscopique de soixante-trois chats pratiqué dans le service a permis de rencontrer quatre fois des lésions de la rate, dont deux lymphosarcomes, une péritonite capsulaire fibrineuse et un hématome sous-capsulaire. D'autre part des lésions ont été trouvées dans deux rates de chat expédiées par des vétérinaires exerçant en pratiaue générale. Chez un chat il s'agissait d'un htmangiosarcome avec métastases hépatiques et chex l'autre d'une infilt ation diffuse par des mastocyta. De plus, on a rencontré des llésions dnas la rate de trois chats parmi quatre-vingt sept autopsies effectuées dans le cadre d'une clientèle génárale. Ces iésions étaient dés métastases multiples d'un adénocarcinome dont la tumeur primitive siègeait dam la glande mammaire, une rupture de la rate et un corps érangers sou capsulaire. Zusammenfassung— Läsionen der Milz wurden bei vier von dreiuiidsechzig in dieser hbteilung sezierten Katzen gefunden, und zwar in zwei Fällen ein Lymphosarkom, in einem Falle eine chron-ische fibrinöse Peritonitis und in einem ein subkapsuläres Hématom. Anomalien fanden sich auch in der Milz von zwei Katzen, die aus der tierxrztlichen Praxis eingesandt wurden. Bei der einen Katze war dies ein Hämangiosarkom mit Metastasen in der Leber, bei der anderen eine weitläufige Infiltration der Mastzellen. Außerdem wurden bei drei von siebenundachtzig in der Praxis sezierten Katzen Milzläsionen gefunden. Diese bestanden am multiplen Metastasen eines Adenokarzinoms der Brustdrüse, einer Milzzerreissung und einem Fremdkörper unterhalb der Milzkapsel. 相似文献