三黄鸡育成期生长曲线的拟合研究

以三黄种鸡为材料,研究了7～21周龄体重的变化,运用Logistic、Gompertz和von Bertalanffy3种非线性模型分别对三黄鸡的生长曲线进行拟合和分析。结果表明,3种模型均能较好地拟合三黄鸡的生长曲线,拟合度(R2)均高于0.977,但von Bertalanffy模型拟合效果最佳。运用3种模型对三黄鸡育成期进行生长曲线的拟合与分析是可行的。     

广西三黄鸡生长曲线拟合与分析

为了解广西三黄鸡的生长发育规律,研究采用Logistic、Gompertz、Bertalanffy 3种非线性模型对广西三黄鸡0周龄～25周龄的生长情况进行拟合与分析。结果表明:4周龄前广西三黄鸡公、母鸡的生长曲线基本一致,10周龄后公鸡的生长速度明显高于母鸡;3种模型均能很好地拟合其生长曲线,拟合度均在0.995以上,其中Bertalanffyu模型在广西三黄鸡生长曲线中拟合最佳,其拟合结果最接近实测体重,其公鸡拐点体重为765.56g,拐点周龄为7.58周龄,母鸡拐点体重为590.07g,拐点周龄为6.96周龄。     

四层层叠本交笼种鸡生长曲线拟合模型研究

为筛选四层层叠本交笼种鸡最佳生长曲线模型,运用Logistic模型、Gompertz模型和Von Bertalanffy模型分别对海兰褐父母代种鸡育雏育成期(1～12周龄)和产蛋期(18～57周龄)体重进行曲线拟合和分析。结果显示:1～12周龄雏鸡(公雏和母雏)的体重均呈逐渐上升趋势,并且公雏的体重生长速度快于母鸡。产蛋期母鸡体重总体呈上升趋势,但51周龄后出现波动。Logistic模型是最适合于拟合公雏体重的模型,Gompertz模型是最适合于拟合母雏体重的模型,而三种模型均可用于产蛋期母鸡体重的拟合。产蛋期母鸡的实际观测值以及拟合值均高于该时期母鸡标准体重上限,建议应在满足母鸡营养需要的前提下适当减料。     

人工养殖东北林蛙生长曲线的拟合与分析

为了解东北林蛙的生长规律,运用Gompertz、Logistic和Von Bertalanffy3种非线性模型分别对东北林蛙一龄和二龄生长期间体重数据进行了曲线拟合和分析。结果表明:3种模型都能很好地模拟东北林蛙的生长曲线,但Logistic曲线模型的拟合效果最好。结果显示,运用3种模型对东北林蛙进行生长曲线的拟合和分析是可行的。     

三黄鸡的生长发育规律研究

对1-22周龄的三黄鸡体重和喂料量进行了测定,计算了绝对生长、相对生长,建立了体重与日喂料量间的回归函数,采用"三和法"拟合了两个生长模型,结果表明:三黄鸡育成期的生长符合生长发育的一般规律,体重与日喂料量间的幂函数为y=1.1078M1.6483(R2=0.9678);Logistic模型与Gompertz模型拟合度均较高(R2分别为0.9590和0.9642),综合分析认为,Gompertz模型为最优生长模型。     

文昌鸡生长曲线拟合的研究

本研究用Logistic、Gompertz和Bertallanffy 3种非线性生长模型对文昌鸡母鸡的生长发育进行拟合.研究结果表明,3种模型均能较好地拟合文昌鸡生长曲线,但是Gompertz模型拟合效果最佳.运用3种模型对文昌鸡进行生长曲线的拟合和分析是可行的,对及时掌握文昌鸡的生长发育规律提供了参考.     

广西三黄鸡胫生长发育规律探讨

通过运用Logistic、Compertz和Bertalanffy模型拟合优质广西三黄鸡生长期体重、胫长和胫宽的生长曲线,发现3种模型都能很好地拟合体重、胫长和胫宽的生长曲线,与体重相比,胫长和胫宽属于早期发育性状,16周龄胫长与胫宽已经非常接近极限值,但体重仍有较大的增长空间。     

太湖鸡生长发育与曲线拟合情况分析

运用Logistic、Gompertz和Bertallanffy3种曲线模型对太湖鸡母鸡0~12周龄生长情况进行了分析和非线性拟合研究。结果表明:3种曲线模型均能较好地拟合太湖鸡的早期生长曲线(R2均为0.999)。分析发现:Logistic生长曲线对禽类早期生长的拟合效果较佳,而对早期生长发育较慢的地方禽种的生长后期拟合效果较差。经比较,3种生长曲线中以Gompertz曲线模型对太湖鸡母鸡的生长拟合效果最佳。通过生长曲线的拟合还能发现饲养管理中存在的问题。     

五华三黄鸡生长曲线拟合及最佳上市时间分析

随机选取1日龄五华三黄鸡200只,公母各半,测定0~20周龄的体重、采食量。分别运用Logistic、Gompertz和Bertalanffy模型拟合其生长曲线,并与采食量函数相结合,进一步推算出最佳上市时间。结果表明:3种模型均能很好地拟合五华三黄鸡生长曲线,各种模型的拟合度(R~2)均在0.996以上,其中Gompertz模型拟合效果最佳,公、母鸡拟合度分别为0.998,0.999。Gompertz模型拟合的五华三黄鸡公、母拐点周龄分别是8.418周和8.210周、拐点体重分别是800.229 g和661.916 g;公、母鸡累计采食量与时间的三次回归方程拟合度分别为0.999,0.998,拟合效果良好;结合经济学中边际理论得出公、母鸡最佳上市时间为16.88周(118 d)和15.63周(110 d)。     

文昌鸡生长模型拟合的研究

试验旨在通过生长曲线的拟合来了解文昌鸡生长发育的规律。用Logistic、Gompertz和Bertallanffy 3种非线性生长模型对公母文昌鸡的生长发育进行拟合。3种模型均能较好地拟合文昌鸡生长曲线,但是Gompertz模型在公母鸡上拟合效果均最佳。公母鸡在4周前生长较一致,4周后,公鸡生长速度明显快于母鸡。运用3种模型对文昌鸡进行生长曲线的拟合和分析是可行的,对及时了解文昌鸡的生长发育规律提供了参考。     

爱拔益加肉鸡父母代后备期的生长性能分析

肉种鸡的后备期生长发育状况对其产蛋期有很大的影响,后备期的生长性能是否达标,是保证产蛋数量和质量的先决条件,也是提高种鸡场经济效益的关键环节。汇总并分析了实际生产中爱拔益加肉鸡父母代种鸡场的第一手资料,结合理想状态下的生产性能标准,通过直观的数据表和曲线图展示了后备期生长性能以周为单位的波动情况,进而对如何缩小实际值与理论值的差距,如何提升后备期生长性能,以及采用何种措施加强饲养管理工作做了深入分析,以期提高广大养殖户对肉种鸡后备期生产管理的重视程度,切实做好产蛋之前的准备工作,以获得更大的经济效益,为市场供应更多更优质的产品做出贡献。     

Relationships of Body Weight,Feathering, and Footpad Condition with Reproductive and Carcass Morphology of End-of-Season Commercial Broiler Breeder Hens

Reproductive efficiency of broiler breeder hens declines with age. Whereas careful feed management can maximize BW uniformity at housing, there is variability in how rate of lay and flock behavioral dynamics will interact with subsequent growth during the breeder phase. This study characterized differences in carcass and reproductive morphology in end-of-cycle commercial broiler breeder hens based on BW, feather coverage, and footpad condition, and we discuss the potential implications of the findings. At 62 wk of age, 537 hens were studied from an original flock of 3,800. Birds were sorted into subgroups based on BW, feather score, footpad score, and whether they were in laying condition when dissected. The average flock BW was 3.56 kg, with means of 2.86, 3.56, and 4.20 kg for the low (LOW), standard (STD), and high (HIGH) BW groups, respectively. A higher proportion of birds from the STD (85%) and HIGH (81%) groups still had a fully formed reproductive tract compared with birds of the LOW (59%) group. The LOW birds in laying condition had a smaller ovary than the STD or HIGH birds. The ovary condition of birds in laying condition was not related to feather coverage. As feather coverage improved, final hen BW increased, demonstrating a potential role of feather coverage in growth efficiency or of BW in level of mating activity. Birds that received a feather score of 5 (complete back feather coverage) and had a normal reproductive tract made up 14.7% of this flock. It is likely that many of these birds were mating very infrequently or possibly not mating, which has implications for maintenance of flock fertility. Some may also have been returning from a molt. Footpad condition was not related to body size. External traits such as BW, feather score, and footpad score can provide insight into flock reproductive condition and male:female interaction.     

不同羽色儋州鸡生长曲线拟合与分析研究

为研究儋州鸡生长发育规律和各阶段的生长速度,本试验采用Gompertz、Logistic和Bertalanffy 3种非线性模型对黑色羽系和麻花色羽系儋州鸡0~18周龄体重生长数据进行拟合和分析,选取黑色羽系、麻花色羽系儋州鸡各200只（公、母各半）,分别于0、2、4、6、8、10、12、14、16和18周龄晨饲前空腹称重并记录,并利用3种非线性模型对儋州鸡生长曲线进行拟合比较分析。结果显示,2种羽色儋州鸡实测生长曲线基本一致,接近于"S"型,符合正常生长发育规律,2种不同羽色儋州鸡母鸡0~18周龄的体重实测值差异不显著（P>0.05）,公鸡0~16周龄的体重实测值差异不显著（P>0.05）,而16~18周龄麻花色羽系公鸡体重显著高于黑色羽系公鸡（P<0.05）。3种非曲线模型拟合度（R²）均在0.992以上,均能较好地拟合2个羽系儋州鸡的生长曲线,且模型的预测曲线与实际观测曲线基本吻合,但Gompertz模型曲线吻合度高于Logistic和Bertalanffy模型曲线,且母鸡比公鸡拟合效果好。本研究结果初步揭示了儋州鸡的生长发育规律和各阶段的生长特征,可为儋州鸡选育、生产和产业化发展提供科学依据。     

Effect of plumage renewal after induced moulting on subsequent laying efficiency and persistence

1. Brown egg layers and dwarf broiler breeder females were force-moulted by different diets. The relationship between the extent of feather replacement and subsequent laying performance was studied. Some brown hens were subjected to metabolic experiments in order to compare post-moult heat production in relation to moulting success. 2. The extent of moulting had a clear effect on the post-moult heat production, and the differences were still present after 6 months in the second year of laying. 3. The extent of feather renewal during moulting showed high and very significant rank correlations with efficiency of food utilisation during the subsequent laying cycle. These correlations were generally higher than those of other features of the moulting procedure (body-weight-loss, minimum weight, duration of pause in laying). 4. The long-term energetic implications of the extent of moulting play an important role in subsequent performances and the persistence of lay during the following year is related to the extent of feather replacement.     

Effects of ad libitum feeding on performance of different strains of broiler breeders

(1) Tolerance to ad libitum feeding was compared in three genotypes of broiler breeder hens: a standard broiler breeder fed ad libitum (SA) or restricted (SR), a slow growing 'label' broiler breeder (L) and an experimental dwarf heavy broiler breeder (E). Two similar experiments were conducted in two distinct research centres. (2) Feed intake and body weight were measured every 3 weeks from hatch to 40 to 49 weeks of age. Egg production and egg abnormalities were recorded. The number of yellow follicles in ovaries was counted at the age of 32 weeks. (3) Body weight was stabilised at 2.2, 3.7 and 5.4 kg after 24 weeks of age in L, E and SA hens, respectively. Growth of the SR hens was similar to that of L up to 20 weeks and stabilised at a similar level to that of E hens after 30 weeks of age. (4) Sexual maturity was delayed by 6 weeks in restricted breeders compared to ad libitum fed hens that started to lay at 20 weeks. SA hens had low egg production and a high proportion of defective eggs, which was largely compensated for by feed restriction. However, productivity of SR hens remained lower than that of L breeders. (5) Compared to the low viability and reproductive fitness observed with SA hens, the E dwarf broiler breeder tolerated ad libitum feeding and had better egg production, fewer egg abnormalities and yellow follicles per ovary and a higher egg production. However, laying rate was still lower than that of the SR and L groups. Energy conversion (kJ/g egg) from 32 to 40 weeks of age was much higher in the SA group than in the other three groups. 6. The feasibility of feeding a dwarf broiler breeder ad libitum calls for further research on implications of specific IGF and GH-receptor expression at the level of the ovary in dw chickens.     

Investigation of the concurrent colonization with Campylobacter and Salmonella in poultry flocks and assessment of the sampling site for status determination at slaughter

Fifty six broiler flocks and 20 laying hen and breeder flocks were sampled in six slaughterhouses for the presence of Campylobacter and Salmonella. Samples were taken from three different sites of the gastrointestinal tract, namely from the crop, the duodenum and the ceca. The prevalence of flocks colonized with Campylobacter and Salmonella was determined and an association between the concurrent colonization with these two pathogens was investigated. Furthermore, the best sampling site for status determination at the slaughterhouse level was evaluated. Of the broiler flocks, 73% were colonized with Campylobacter, whereas 13% were Salmonella-positive at slaughter. Concerning the laying hen and breeder flocks, all flocks were colonized with Campylobacter and 65% of the flocks were Salmonella-positive. No association was found between Campylobacter and Salmonella occurrence in broiler flocks. Since all laying hen and breeder flocks were colonized with Campylobacter, no association between the concurrent colonization with the two pathogens could be determined. At the slaughterhouse level, sampling only the duodena was sufficient to determine the Campylobacter status of poultry flocks, whereas the three sampling sites had to be analyzed to detect all flocks colonized with Salmonella.     

肉仔鸡生长和胴体、羽毛蛋白质沉积模型的建立

选用1日龄爱拔益加肉仔鸡健康雏鸡240只，分性别进行饲养试验和比较屠宰试验。在42d的试验期内，每间隔7d测定试验鸡的体重及相应的体组成。采用Gompertz方程拟合公母肉仔鸡的生长曲线，并通过不同数学公式分别描述肉仔鸡胴体蛋白重和羽毛蛋白重与活重的关系，筛选出最佳模型并与生长曲线组合。分别对生长曲线和筛选的模型进行微分，建立活体增重、胴体蛋白沉积量、羽毛蛋白沉积量与日龄之间的动态函数关系，精确反映肉仔鸡的生长和蛋白质沉积规律。     

罗曼肉鸡生长发育规律研究

对1～9周龄的罗曼肉鸡体重进行了测量,计算了绝对生长、相对生长指标,运用Logistic、Gom-pertz和von Bertalanffy三种非线性模型对其累积生长情况进行了拟合与分析。结果表明：罗曼肉鸡在4周龄前生长缓慢,4周龄后逐渐加快;Gompertz模型和von Bertalanffy模型均能很好地拟合罗曼肉鸡的生长曲线（R2分别为0.9989和0.9998）,尤其是von Bertalanffy模型效果更佳,此模型拟合的生长曲线拐点日龄为39.23d,拐点体重为1512.09g。     

艾维茵48父母代种鸡产蛋性能分析

分析5250只26周龄的艾维茵48父母代种鸡的产蛋情况并与标准比较，了解产蛋期肉种鸡产蛋性能的变化规律及饲养管理情况。结果表明，随鸡群周龄的增大，累积死淘率逐渐上升，且在产蛋末期明显上升；鸡群产蛋率在26-30周龄低于标准，在产蛋末期产蛋率下降幅度增加；鸡群的合格蛋率相对较高；合格蛋受精率在26-34周龄上升缓慢且低于标准受精率，此后呈波动性缓慢下降，且始终低于标准受精率。在种鸡生产中，加强饲养管理可以提高种鸡产蛋性能。     

饲料中使用棉仁粕、菜籽粕对种鸡生产性能的影响

对饲料中棉仁粕、菜籽粕不同用量对肉种鸡生产性能的影响进行了研究.结果表明:在8%以下使用量时对鸡群产蛋率、死淘率、孵化性能、后代生长发育、鸡体中毒反应等方面的影响不显著.