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在低水平豆粕型母猪哺乳期饲料中添加合成赖氨酸以平衡日粮的营养水平,不会对母猪当前和以后的生产性能产生负面影响,虽然合成氨基酸的成本增加了,但整体生产成本能够下降。 相似文献
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Fragkou IA Mavrogianni VS Cripps PJ Gougoulis DA Fthenakis GC 《Veterinary research》2007,38(4):525-545
We studied the possible effects of bacterial populations within the teat duct, in the pathogenesis of ovine mastitis. In experiment I, 32 ewes were allocated into group A (ewes from which we isolated (+++ growth) coagulase-negative staphylococci), B (ewes from whose duct we isolated (+ growth) coagulase-negative staphylococci) or C (ewes from which we isolated Bacillus spp.) and subdivided into A1, B1, C1 (n=4; challenged by deposition of 1.250 cfu of Mannheimia haemolytica into the teat duct) or A2, B2, C2 (n=4; used as uninoculated controls); group D (n=8) contained ewes with no bacteria in their teat ducts and were challenged as above. There were less bacteriological isolations of flora (P = 0.018) and challenge (P<0.05) organisms from A1 than from A2 and D ewes; the severity of pathological findings in A1 (summed up score: 27) ewes was smaller than in D (summed up score: 36) ewes (P = 0.038). No such findings were evident with B1 or C1 ewes (P>0.4). In experiment II, ewes (groups E and F, n=6) from whose duct we isolated coagulase-negative staphylococci (+ growth) were used; in group G (n=6) ewes with no bacteria in their teat ducts were included. Teat chapping was applied in E and G ewes. All E ewes developed acute clinical mastitis within 24 h after teat chapping, although we had carried out no challenge; there were more bacteriological isolations of flora organisms from E than from F and G ewes (P < 0.001); the severity of pathological findings in E (score: 28) was greater than in F (score: 3) or G (score: 14) ewes. In experiment III, eight ewes with no bacteria in their teat ducts were allocated into group H or I (n=4) and challenged into the teat (group H) or into the gland (group I) with 10(6) cfu of a Staphylococcus simulans recovered from the teat duct of a group E ewe. Group H ewes developed transiently clinical followed by subclinical mastitis (based on bacteriological and cytological evidence), whilst group I ewes developed severe clinical disease. We conclude that staphylococcal flora present in high numbers within the teat duct of ewes can afford some protection against invading microorganisms. However with impeded defence mechanisms of the teat, the same flora may invade the mammary parenchyma and cause clinical mastitis. 相似文献
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１９９９年５月 ４日,购进天津大成公司 １ｄＡＡ雏鸡１５４只,随机分成两组,每组７７只。饲养在同一舍内的两个网床（长２．７０ ｍ,宽２．６５ ｍ,高０．４ｍ的钢床两个,床面上铺网眼直径为 １．５ ｃｍ的塑料网）上,床面离地１ｍ。正常饲养、观察、适应３ｄ,５月７日称重调整,使两组鸡的平均体重无显著差异（Ｐ＞０．０５）,并开始试验。 试验期基础饲料全部采用天津大成公司饲料厂生产的肉仔鸡全价颗粒料, １７ ｄ前用 ３１８０号料;１８～３４ ｄ用 ３２８０号料,３４～４４ ｄ用 ３３８６号料。 在试验组日粮中添加 ０．… 相似文献
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看来当蛋鸡饲喂含高水平维生素D3的日粮时,紫外线似乎会影响蛋壳的颜色。因此,蛋鸡生产者可能需要更加地关注日粮中维生素D3的水平了,以避免光线对蛋壳造成的麻烦。 相似文献
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由猪传统日粮所用饲料原料带来的成本和供应问题促使人们寻找更新的饲料原料,并以求最大程度地利用所选原料中的养分。 相似文献
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弯曲杆菌污染是人类健康的一大威胁。通常认为该菌仅存在于肉鸡的胃肠道内。然而,美国的一项研究表明该菌也可以存在于其他内脏器官中,甚至存在于1日龄雏鸡体内。 相似文献