排序方式: 共有42条查询结果,搜索用时 15 毫秒
1.
当今世界养猪生产力和生产效率在不断提高。母猪生产力以每头母猪每年产断奶仔猪数表示。决定母猪生产力的两个组分是年产窝数及断奶窝仔数。这两个性状的遗传力都很低,需靠高水平的管理技术及良好的营养条件才能得以提高。 相似文献
2.
3.
我国地方畜禽品种分类方法探析 总被引:2,自引:0,他引:2
我国地方畜禽品种分类方法探析刘荣宗(湖南农业大学动物科学技术学院长沙410128)1.导言我国地方畜禽品种资源丰富多采,为当今世界各国所瞩目。据不完全统计,各类家畜的地方品种或类群约有200多种。其中,猪即有100多个地方类群,已基本调查清楚并列入了... 相似文献
4.
5.
6.
同期发情可使山羊发情集中,也有助于为难以进行发情鉴定母羊配种。使产羔时间集中,便于培育、饲喂和采取统一的防病措施。诱发发情可用以引起山羊非繁殖季节繁殖,以便全年供奶均衡。但母羊在炎热气候条件下受胎率及胎儿成活率下降。母山羊在非繁殖季节产羔,产奶量会降低20%。发情同期或诱导非繁殖季节繁殖的效果受季节、气候、海拔高度、饲管方式以及母羊的品种和年龄等因素的影响。没有发生过产羔障碍的母羊诱发发情效果较好。于配种前2~4周饲喂高能日粮能有效提高繁殖率。 相似文献
7.
美国乔治大学的 R·W·Seerley 博士在一次学术会议上指出,对于由于断奶造成激反应的仔猪,在其饲粮中添加有机酸可起到良好的作用。Seerly 在他1985年岀版的猪营养研究论丛中提出,经试验证明,柠檬酸和延胡索酸都均作为饲料添加剂。据报道,在幼猪饲粮中添加延胡索酸可收到较好的效果。在每公斤饲粮中添加30克柠檬酸与每公斤饲粮添加15克延胡索酸同对照组相比,能使增重速度 相似文献
8.
西德Degussa认为,在断奶后头几周的仔猪饲粮中添加有机酸效果良好,可消除断奶仔猪常见的生长停滞现象。很多研究表明,在小猪饲粮中加入有机酸,可通过影响肠道微生物群落数量、激活消化酶以及促进能量利用而提高小猪生产性能,其结果是使饲料转化率和日增重提高。最近,西德的Kirchgessner发现,甲酸钙是有机甲酸一种很有价值的来源。当在仔猪饲粮中添加1.3%的甲酸钙时,饲料转化率提高3.8%。试验还表明,当甲酸钙添加量在0.9%以上时,可减少仔猪下痢的发病率。荷兰也提供了进一步验证甲酸钙的结果。 相似文献
9.
10.
OBJECTIVE: Evaluation of use of a supernumerary teat as a pedicle graft to repair experimental teat tip damage in cattle. STUDY DESIGN: Experimental study. ANIMALS: Mature, non-gravid hybrid cows with > or =1 supernumerary teat. METHODS: The main teat and adjacent supernumerary teat were examined for patency by ultrasound with a 8 MHz linear array transducer. The tip of the main teat was resected at the junction of cistern and canal. The supernumerary teat was partially resected semi-circumferentially at the cranial aspect of the base to maintain vascular supply and transplanted by end-to-end anastomosis. The pedicle of the supernumerary teat graft was amputated in stages starting at 14 days, again at 16 days and separated at 18 days. Reconstructed teat patency was evaluated at intervals by ultrasonography and confirmed at 50 days by histopathology. Repeated measures ANOVA was used to compare the measurements of luminal diameter between days; significance was set at P<.05. RESULTS: All reconstructed teats were patent. Decreased luminal diameters were detected at 25, 32, 39, and 46 days by ultrasonography. On histopathology, granulation and epithelial (mucosal) proliferation contributed to luminal reduction. CONCLUSIONS: In this experimental model of an acute damage to a teat tip, supernumerary teat grafting was successfully used to restore teat anatomy. CLINICAL RELEVANCE: Supernumerary teat pedicle grafting may be considered as a salvage technique for reconstruction of a damaged bovine teat in cows that have an adjacent patent supernumerary teat. Function of the reconstructed teat in a lactating cow remains unknown. 相似文献