肉兔不同杂交组合的生产性能测定

养兔具有投资少、见效快、效益高的特点，饲养规模可大可小，饲养方式多种多样，是当前广大农村实现农业增效、农民增收的好项目。但是，养兔效益可受品种、繁育方式、饲料营养、饲养管理等多种因素的影响。据生产实践，作为商品兔，一般杂种兔的经济效益高于纯种兔，杂种后代的增重速度可比纯种兔提高10％以上。但不同品种间杂交，其杂交效果各不一样。     

德昌饲养加利福尼亚肉兔繁殖蝴相关通径分析

摘要：经设点测定加利福尼亚肉兔的繁殖性状,经相关通径分析,总的多元决定系数较大,∑d=0．6334,表明影响的主要性状已包括在其中,从相关通径、决定系数分析看出,断乳窝重与产仔数,泌乳力相关程度一致性较强,是影响断乳窝重的重要性状,用于研究区生产中的选择工作、提高繁殖性能是有参考意义的。     

肉兔的繁殖技术要点

1科学地确定初配年龄公母兔达到性成熟后,虽然已能配种繁殖,但因身体各器官仍处于发育阶段,未能达到体成熟,此时不能配种,若此时配种(称为过早配种)不仅会影响公母兔的生长发育,而且配种后受胎率低,产仔数少,仔兔初生体重小,成活率低;但也不能过晚配种,过晚配种会影响繁殖数量,并容易引起种兔本身肥胖,生殖机能降低。确定肉兔的初配年龄,主要根据体重和月龄来决定,在正常饲养管理条件下,公母兔体重达到该品种标准体重的70%时,即已达到体成熟,就可开始配种繁殖。一般认为,小型品种初配年龄为4～5月龄,体重2.5～3kg;中型品种为5～6月龄,体重3.…     

肉兔繁殖的关键技术

饲养肉兔的目的在于为市场提供营养丰富、优质安全的兔肉.要想获得多而好的兔肉,必须搞好肉兔的繁殖,增加肉兔的数量,从而提高养兔的经济效益.     

美国新西兰肉兔生产性能

一、饲养管理我场的兔舍为四周敞开的双列式钢筋水泥笼壁和地面,每幢兔合分上、中、下3层,共计195个笼位。由1名饲养员喂养并兼种2亩青饲料,常年四季青绿多汁饲料供应较均匀,精青饲料比例为1:1.8～1.9.精料中颗粒饲料占80%,粉料占20%,颗粒饲料的常用配方为:玉米20.四号粉15,麸皮20.豆饼10,干草粉20,统糠10,鱼粉3,骨粉1.5.食盐0.5;或玉米15,麸皮30,米慷20,糠饼10,鱼粉5,统糠20,贝壳粉2,食盐0.5.每千克颗粒饲料     

提高肉兔生产性能的措施

一、影响肉兔肥育性能的因素1.品种不同生产类型的家兔肥育性能不同,以肉用兔的肥育性能最好,皮肉兼用兔次之,皮用兔较差,毛用兔肥育效果最差。既使同是肉用品种,不同品种的肥育性能也不同,大型品种早期生长发育较快,净增重较高。中型兔早期生长不如大型兔,但比小型兔快,而且饲料利用率高于大型品种。目前,从国外引进的肉用兔种有比利时兔、新西兰白兔、加里福尼亚兔、丹麦白兔、德国巨型兔、青紫蓝兔、日本大耳白兔、法国公羊兔等。国内品种有哈尔滨白兔、塞北兔、中国白兔等。引入品种中,新西兰白兔、加里福尼亚兔、比利时兔、日本大耳白兔生长发育快,肉质好,屠宰率高,适应性强。法国公羊兔生长速度慢,肉质差,屠宰率     

肉兔的冬季繁殖

多年来,在发展肉兔生产中,群众习惯春买、夏繁、秋卖、冬不留。认为冬季气温低、天气冷、日照短、青饲料缺乏,不能繁殖,不好养。其实不然,肉兔不但可以冬繁,而且能提高成活率。因为寒冬腊月,大多数微生物病原菌的生长繁衍受到了抑制,一些传染病及寄生虫病,和炎夏相比大大减少,成活率明显提高。只要饲料准备充足,就十分有利于肉兔的冬季繁殖。实践证明,凡是冬季繁殖的小兔比其它季节成活率都高,自身抗病力强,母兔的利用率高,育种场由年产4窝提高到5窝,商品母兔可提高7-8窝。但是,如果管理不当,易使公母兔性欲下降,小     

肉兔杂交组合的繁殖性能测定

肉兔杂交组合的繁殖性能测定,产仔数以新×花组最高,其次为新×比组;断奶窝重以新×比组最高,其次为新×花组;成活率以新×花组最高,其次是新×比组.根据试验结果比较,产仔数、断奶窝重、成活率均以新×花、新×比杂交组为最高,说明这两个杂交组合亲和力好,表现出较高的繁殖性能.因此,商品肉兔场从生产效益出发,宜采用不同品种杂交组合,以有利繁殖性能和生产性能的提高.     

维生素及类维生素对母猪繁殖性能的影响

当前非洲猪瘟给我国养猪业造成很大的损失,繁殖母猪的存栏量急剧减少,造成猪肉供需平衡失调。那么,如何提高母猪的繁殖性能,提供更多的商品猪,成为养殖场管理者关注的焦点。文章就提高母猪繁殖性能的关键环节和维生素及类维生素对母猪繁殖性能影响进行综述。     

某猪场母猪繁殖性能预测和logistic回归分析

为了衡量猪场生产效率,研究根据某公司7个分场繁殖母猪2016—2019年的生产记录,运用时间序列分析预测母猪繁殖性能的未来短期趋势,发现母猪未来一段时间的生产性能不会出现较大变动,与实际值较吻合,说明时间序列对母猪繁殖性能方面的预测,有较强的实用价值;再通过建立logistic回归模型,进行模型分析以寻找影响母猪繁殖性能的关键因素,进一步确定胎次是影响母猪繁殖性能重要因素。并且该模型还可用于其他生产指标的因素分析,可以为提高母猪群繁殖性能提供科学依据。     

公猪繁殖性能评定

随着规模化养猪业的发展及人工授精技术的普及,公猪繁殖性能已是影响猪场经济效益的重要因素。如何准确评定公猪的繁殖能力,保证人工授精效果,进而保证母猪的繁殖性能的发挥,是养猪人工作中的重要环节。生产实践中最常用的是通过显微镜对猪精细胞水平进行检测。科研人员也在一直研究影响人工授精效果的因素,将精液的检测从细胞水平上升至分子水平,再用分子标记手段将公猪繁殖性能由检测提前至预测,最大限度地保证公猪的繁殖性能,保证优良公猪的性能得到最大程度的发挥。文章从精液品质、人工授精效果、分子水平检测、标记物等几个方面介绍公猪繁殖性能评价时需要衡量的指标,为公猪繁殖性能评定提供参考。     

Culling of dairy cows. Part II. Effects of diseases and reproductive performance on culling in Finnish Ayrshire cows

The effects of 15 diseases and reproductive performance on culling were studied in 39 727 Finnish Ayrshire cows that calved in 1993 and were followed until culling or next calving. Survival analysis, using the Cox proportional hazards model, was performed with diseases and pregnancy status as time-dependent covariates. Parity, calving season and herd were included as covariates in every model. The effect of the number of inseminations was also studied.

The farmer's knowledge of the cow's pregnancy status had a significant effect on culling. It varied according to the stage of lactation a cow was in; the earlier the farmer knew a cow was pregnant, the smaller was the risk of culling. If a cow had not been inseminated at all, her risk of culling was 10 times higher than if she was inseminated once. If a cow was inseminated more than once, she had a slightly lower risk of being culled than a cow inseminated only once. The effect of parity decreased when pregnancy status and number of inseminations were added to the model, indicating that part of the parity effect was accounted for by reproductive performance. Including diseases in the model with pregnancy status and the number of inseminations did not change the effects of reproductive performance on culling.

Mastitis, teat injuries and lameness had the greatest effect on culling (whether adjusted for reproductive performance or not), increasing the risk of culling, followed by anestrus, ovarian cysts and milk fever. In general, the effects of diseases decreased when reproductive performance was also accounted for in the model. When pregnancy status was included in the model, the effects of anestrus and ovarian cysts became slightly more protective, but when the number of inseminations was also considered, they became non-significant at the beginning of lactation and they increased the risk of culling at the end of lactation.

Sensitivity analysis, which was run to evaluate the effects of our censoring mechanism on the results, indicated that the censoring times (i.e., the time of next calving) were not fully independent of the event (culling) times; the effects of the diseases and pregnancy status at the very end of the lactation changed slightly from the original model.     

不同蛋白质水平对獭兔繁殖性能的影响

选择年龄、体重基本一致,生长发育正常的健康獭兔种母兔24只,随机分成对照组以及A、B、c3个试验组,每组6只,对照组饲喂养殖场现有日粮（蛋白水平为15％）,试验组分别饲喂蛋白质水平为16％、18％、20％的日粮,研究不同蛋白质水平对獭兔繁殖性能的影响。结果表明。不同营养水平对窝产仔数、初生窝重没有明显影响,各组差异不显著（P〉0．05）,但对泌乳力、断奶窝重、断奶个体重等有明显影响。B组的泌乳力、断奶窝重与对照组相比差异显著（P〈0．05）,分别比对照组提高47．6％和1573．42g;断奶个体重,A组和B组均显著高于对照组（P〈0．05）,比对照组分别高30．9％和47．4％,B组显著高于A组（P〈0．05）,比A组高12．6％,C组与对照组差异不显著（P〉0．05）;各组断奶成活数、成活率差异不显著（P〉0．05）。     

繁殖营养素对西杂母牛繁殖性能、产后健康及犊牛生长性能的影响

摘要：［目的］探究繁殖营养素对西门塔尔杂交母牛繁殖性能、产后健康及犊牛生长性能的影响。［方法］试验对33头390kg左右妊娠8-9月的初配西门塔尔杂交母牛饲喂不同添加量的繁殖营养,对母牛繁殖性能、产后健康及犊牛生长性能的数据进行分析。［结果］饲喂10g/(头·d)繁殖营养素母牛人工助产率较对照组大幅降低,且犊牛成活率提高,犊牛发病率减少。第一次发情时间提前7.42d,且受胎率也有所提高;饲喂10g/(头·d)繁殖营养素大幅度降低了母牛胎衣不下、子宫炎和乳房炎疾病的发病率;添加了10g/(头·d)繁殖营养素组的犊牛从出生到产后3月龄,其体重和体尺都有不同程度提高。［结论］母牛日粮中添加10g/(头·d)繁殖营养素能提高母牛繁殖性能、降低母牛产后疾病的发生率以及一定程度上提高犊牛的生长性能。     

Dietary fiber and microbiota interaction regulates sow metabolism and reproductive performance

Dietary fiber is a critical nutrient in sow diet and has attracted interest of animal nutritionists for many years. In addition to increase sows’ satiety, dietary fiber has been found to involve in the regulation of multiple biological functions in the sow production. The interaction of dietary fiber and gut microbes can produce bioactive metabolites, which are of great significance to sows'' metabolism and reproductive performance. This article reviewed the interaction between dietary fiber and gut microbes in regulating sows'' gut microbial diversity, intestinal immune system, lactation, and production performance, with the aim to provide a new strategy for the use of dietary fiber in sow diets.     

Dietary supplementation of Bacillus subtilis PB6 improves sow reproductive performance and reduces piglet birth intervals

We investigated the effects of dietary supplementation with Bacillus subtilis PB6 (B. subtilis PB6) during late gestation and lactation on sow reproductive performance, antioxidant indices, and gut microbiota. A total of 32 healthy Landrace × Yorkshire sows on d 90 of gestation were randomly assigned to 2 groups, with 16 replicates per group, receiving basal diet (CON) or the basal diet + 0.2% B. subtilis PB6, containing 4.0 × 10⁸ CFU/kg of feed (BS). The litter sizes (total born) and numbers of piglets born alive were larger in the BS group (P < 0.01), whereas the weights of piglets born alive and the piglet birth intervals were lower in the BS group (P < 0.05). Although the litter weights and piglet bodyweights (after cross-fostering) were lower after BS treatment (P < 0.05), the litter sizes, litter weights, lactation survival rate, and litter weight gains at weaning were higher in BS group (P < 0.05). The concentrations of malondialdehyde (MDA) in the sow sera at parturition were lower in the BS group (P < 0.01). The serum total antioxidant capacity (T-AOC) at parturition and the serum catalase (CAT) concentrations on d 21 of lactation were higher in the BS group (P < 0.05). Dietary supplementation with B. subtilis PB6 (P < 0.05) reduced the serum endotoxin concentrations in the sows and the serum cortisol concentrations of the piglets at d 14 of lactation. The α-diversity indices of microbial were higher in the CON group (P < 0.05). At the phylum level, B. subtilis PB6 supplementation increased the relative abundances of Gemmatimonadete and Acidobacteria (both P < 0.01) and reduced those of Proteobacteria, and Actinobacteria (both P < 0.05). At the genus level, B. subtilis PB6 supplementation increased the relative abundance of Ruminococcaceae_UCG-013 cc (P < 0.05) and reduced that of Streptococcus (P < 0.05). This study demonstrated that adding 4.0 × 10⁸ CFU/kg B. subtilis PB6 to sows’ feed during late gestation and lactation could shorten piglet birth intervals, enhance the growth performance of suckling piglets, and improve the gut health of sows during late gestation.     

美系与德系獭兔杂交组合的繁殖性能观测

以美系(A系)和德系(G系)獭兔为基础育种群体,进行正、反交及其子代杂交。其中选择美系(A系)和德系(G系)獭兔公兔各20只,母兔各200只左右;进行正、反杂交试验,并以其杂种后代美德獭兔(AG系)和德美獭兔(GA系)继续进行杂交试验;并以公兔组建家系,对所有杂交组合的繁殖性能和后代体重生长性能进行系统测定,优化杂交组合,选择优良家系。美系与德系獭兔正反杂交组合的繁殖性能均大于德系獭兔亲本(P<0.01),在亲本中,美系獭兔繁殖性能显著优于德系獭兔(P<0.01);在所有杂交组合中,以德美獭兔♂×美德獭兔♀组合的平均产仔数(8.18只)、初生窝重(436.41 g)、断乳活仔数(7.6只)为最高,杂交优势率亦最高。美系獭兔♂×德系獭兔♀杂交组合家系间的产仔数、断乳活仔数、断乳成活率等繁殖性状总体上差异不显著(P>0.05),部分家系间初生窝重有显著差异。德系獭兔♂×美系獭兔♀杂交组合家系间仅少数家系间初生窝重有显著差异(P<0.05);德美獭兔♂×美德獭兔♀家系间的产仔数、初生窝重、断乳活仔数、断乳成活率等繁殖性状均无显著差异(P>0.05)。以德美獭兔(GA)♂×美德獭兔(AG)♀为最佳杂交组合。     

The reproductive performance of sows after PRRS vaccination depends on stage of gestation

In order to minimize the effects of porcine reproductive and respiratory syndrome (PRRS) on stillbirth, mummification, and neonatal mortality in swine herds, many producers have vaccinated their herds using a modified-live virus vaccine. The purpose of this study was to determine the association of the PRRS modified-live vaccine and reproductive performance by stage of gestation when the vaccine was administered. A total of 47 swine herds from Ontario and Manitoba, Canada, and from the mid-western USA were included in the study. Participating farms had vaccinated all of their sows at one point in time when they used the vaccine for the first time. The reproductive performance of sows that farrowed in the year prior to use of the vaccine was compared to that of sows vaccinated in each of five stages of gestation and in the gestation that followed the initial use of the vaccine. Sows vaccinated at any time during gestation had a reduced number of pigs born alive, a reduced number of pigs weaned per litter, and increased number of stillborn pigs and an increased number of mummified pigs compared to the sows that farrowed prior to use of the vaccine. The largest association was seen in sows that were vaccinated in the last four weeks of gestation. The largest losses were observed in those herds that were vaccinated concurrently with the initial PRRS herd outbreak. These results suggest that the modified-live vaccine should only be administered to non-gestating sows.