基于Internet/Intranet集约化奶牛场精细养殖技术平台的构建

在windows 2000 advanced Server环境上，利用SQL Server 2000网络数据库系统，通过将集约化奶牛场生产管理过程基本要素数字化并建成奶牛场精细养殖数据库体系框架后，结合了B／S与C／S两种结构的优点，构建了基于Internet／Intranet集约化奶牛场精细养殖技术平台。按预设的奶牛生命周期各种基本参数，利用技术平台自动产生的模拟数据，全面验证了平台开发的预期目标，即建成的平台系统能按奶牛个体跟踪至少5代以上的祖先系谱，能监测可能出现的子代近交系数，能动态反映由不同类型牛只组成的牛群结构，尤其在采集奶牛个体体况信息的基础上，根据系统设置预测养分需要的模型，精准计算个体奶牛的日营养需要并优化日粮配方，基本实现了以个体信息为基础的奶牛精细饲养。最后指出该技术平台的发展方向是建立以构件技术为基础的三层体系结构，为Web Server应用提供更大的空间。     

不同近交程度对DⅥ系猪经济性状的影响

中国瘦肉型猪新品系——DⅥ四世代猪的平均近交系数（％）为3．1620，按个体近交系数（％）的大小分成4个组：0，03906～1．9531，2．3438～62500和12．8906～25．0000，对每个组的繁殖、生长和肥育性状进行分析，结果：繁殖性能以近交系数（％）2．3438～6．2500组的较好，当近交系数（％）超过12．8906时，DⅥ系猪的繁殖、生长胆有性状都有下降趋势。     

罗马数字法计算近交系数点滴

<正> 罗马数字法,亦称亲缘结构式法,就是用罗马数字表示共同祖先在系谱中所处的代数和位置,中间用短横线(—)连结,横线左右两边的罗马数字分别相应地表示共同祖先在母系和父系方面所占的代数,父母为第1代祖先,祖父母和外祖父母为第2代祖先,余类推。用罗马数字法计算近交系数对于复杂系谱也不需制成结构式系谱,通路的条数不会被遗漏或重复,计算简便。现以计算Z个体的近交系数为例,说明使用这一方法时值得注意的几个问题。     

近交系猪群的现代化饲养管理

1近交系的命名 近交系是由全同胞兄妹或亲子连续20世代交配而育成的，其近交系数应达到或大于98．6％，且所有个体可以追溯到一对共同祖先。亲子配或全同胞配是近交的2种极端形式，也称“急骤近交”。     

近交对中国荷斯坦牛泌乳性能的影响

为研究近交对中国荷斯坦牛泌乳性能影响，收集2008年5月至2022年2月河南37家奶牛场67 150头中国荷斯坦牛1～5胎次共128 282条泌乳性能记录数据，筛选后用于分析的数据共23 933头奶牛40 737条数据。个体近交系数F_ped是基于系谱信息采用R(v4.1.2)nadiv包计算，将奶牛按照近交系数分为无近交组(F_ped=0)、低近交组(F_ped≤6.25%)和高近交组(F_ped>6.25%)3个组。采用R(v4.1.2)方差分析(aov)函数，分析不同近交系数分组对泌乳性能指标的影响。采用DMU软件(v6)和动物模型按照总数据和分胎次对泌乳性能进行近交衰退评估，在评估模型中近交系数作为协变量，近交系数回归系数即为近交衰退效应值，并进行显著性检验。结果表明：近交对奶牛305 d产奶量、305 d乳脂量和305 d乳蛋白量有极显著影响；近交系数每增加1%,305 d产奶量、305 d乳脂量和305 d乳蛋白量分别减少8.55 kg(P<0.01)、0.22 kg(P<0....     

近交程度对杜洛克母猪繁殖性能的影响

对7 051窝不同近交系数的杜洛克母猪繁殖数据进行统计分析,发现近交程度对杜洛克母猪繁殖性能的影响主要表现在产仔总数、产活仔数和产弱仔数方面。近交系数第3组（3.125%～6.25%）与其他组间在产仔总数、产活仔数和产弱仔数方面存在显著（P<0.05）或极显著差异（P<0.01）。母猪2胎、3胎、4胎、5胎次的产仔总数、产活仔数、产弱仔数均以第3组最高。说明通过适度近交,可以较快地剔除有害基因、增加遗传稳定性,可以较好地降低有害基因对母猪繁殖性能的影响。     

奶牛热应激的预防与控制

在北方地区，炎热盛夏（气温在30℃以上）的时间一般在3个月左右。在此期间的高温环境中，奶牛在生理和健康等方面会产生一系列的不适应或功能紊乱，导致健康、生产性能和繁殖性能等诸多方面产生较大的负面影响，严重时还会导致奶牛死亡，这种现象称之为奶牛的“热应激”。     

人工诱乳技术及其应用效果

人工诱乳技术及其应用效果内蒙古乌盟冷冻精液站（０１２０００）周宁聪在奶牛业中存在着由于繁殖障碍造成奶牛久配不孕的现象，特别是对于一些个体养牛户的奶牛，这种现象更为普遍。这些奶牛不产犊，不产奶或只产少量奶而白消耗饲草饲料，严重地影响奶牛的经济效益，从而...     

与不可消化中性洗涤纤维相比，奶牛瘤胃中可消化中性洗涤纤维易被选择性保留

试验数据由4个试验中瘘管奶牛（60个试验个体）得到。仅自由采食不同种类粗饲料或补充混合精料。不同时间测定瘤胃排空,在平均瘤胃池和平均日流量的基础上进行纤维动力学测定。不可消化中性洗涤纤维（INDF）在瘤胃的平均滞留时间（MRT）范围从35h～92h。测定MRT时使用传统的瘤胃排空技术,以一级动力学和单室模型为基础,过高估计了可消化中性洗涤纤维（DNDF）的滞留时间,     

美国奶牛生产性状和体型外貌性状的遗传评定

美国对奶牛生产性能和体型外貌性状的遗传评定采用的是动物模型计算方法，动物模型是计算预期传递力（PTA）最先进的方法。体型外貌性状的遗传评定由美国荷斯坦奶牛协会承担，生产性能的预期传递力、体细胞评分、生产年限和净价值（NetMerit）的计算则由美国农业部家畜改良计划实验室（USDA－AIPL）进行。动物模型的评定方法是根据动物个体与其它评定的个体的亲缘关系来进行的。动物个体本身、祖先和后代的信息，与被评定个体间的所有已知亲缘关系信息综合到一起，并利用了母系信息，包括母系祖先信息和母系后裔信息。在动物模型的遗…     

Population structure and genetic variability in the Murrah dairy breed of water buffalo in Brazil accessed via pedigree analysis

The objective of this study was to use pedigree analysis to evaluate the population structure and genetic variability in the Murrah dairy breed of water buffalo (Bubalus bubalis) in Brazil. Pedigree analysis was performed on 5,061 animals born between 1972 and 2002. The effective number of founders (fe) was 60, representing 6.32?% of the potential number of founders. The effective number of ancestors (fa) was 36 and the genetic contribution of the 17 most influent ancestors explained 50?% of the genetic variability in the population. The ratio fe/fa (effective number of founders/effective number of ancestors), which expresses the effect of population bottlenecks, was 1.66. Completeness level for the whole pedigree was 76.8, 49.2, 27.7, and 12.8?% for, respectively, the first, second, third, and fourth known parental generations. The average inbreeding values for the whole analyzed pedigree and for inbreed animals were, respectively, 1.28 and 7.64?%. The average relatedness coefficient between individuals of the population was estimated to be 2.05?%??the highest individual coefficient was 10.31?%. The actual inbreeding and average relatedness coefficient are probably higher than estimated due to low levels of pedigree completeness. Moreover, the inbreeding coefficient increased with the addition of each generation to the pedigree, indicating that incomplete pedigrees tend to underestimate the level of inbreeding. Introduction of new sires with the lowest possible average relatedness coefficient and the use of appropriate mating strategies are recommended to keep inbreeding at acceptable levels and increase the genetic variability in this economically important species, which has relatively low numbers compared to other commercial cattle breeds. The inclusion of additional parameters, such as effective number of founders, effective number of ancestors, and fe/fa ratio, provides better resolution as compared to the inclusion of inbreeding coefficient and may help breeders and farmers adopt better precautionary measures against inbreeding depression and other deleterious genetic effects.     

Rates of inbreeding and genetic diversity in Iranian Holstein Cattle

The accumulation of inbreeding and the loss of genetic diversity is a potential problem in Holstein dairy cattle. The goal of this study was to estimate inbreeding levels and other measures of genetic diversity, using pedigree information from Iranian Holstein cattle. Edited pedigree included 1 048 572 animals. The average number of discrete generation equivalents and pedigree completeness index reached 13.4 and 90%, respectively. The rate of inbreeding was 0.3% per year. Effective number of founders, founder genomes, non‐founders and ancestors of animals born between 2003 and 2011 were 503, 15.6, 16.1 and 25.7, respectively. It was proven that the unequal founder contributions as well as bottlenecks and genetic drift were important reasons for the loss of genetic diversity in the population. The top 10 ancestors with the highest marginal genetic contributions to animals born between 2003 and 2011 and with the highest contributions to inbreeding were 48.20% and 63.94%, respectively. Analyses revealed that the most important cause of genetic diversity loss was genetic drift accumulated over non‐founder generations, which occurred due to small effective population size. Therefore, it seems that managing selection and mating decisions are controlling future co‐ancestry and inbreeding, which would lead to better handling of the effective population size.     

Population structure of Mazandaran native fowls using pedigree analysis

The objective of this study was to use pedigree analysis to evaluate the population structure and genetic variability of the Mazandaran native fowls in Iran by quantifying the pedigree completeness index, effective population size, genetic diversity, inbreeding level, and individual increase in inbreeding. The pedigree completeness analysis showed 3.31 full, 10.19 maximum, and 6.30 equivalent generations. The effective number of founders (f _e) was 131, representing 5% of the potential number of founders. The effective number of ancestors (f _a) was 81, and the genetic contribution of the 37 most influent ancestors explained 50% of the genetic variability in the population. The ratio f _e/f _a (effective number of founders/effective number of ancestors), which expresses the effect of population bottlenecks, was 1.62. The inbreeding coefficient increased over generations and the average was 1.93%. The average relatedness coefficient between individuals of the population was estimated to be 2.59%. The effective population size, based on the number of full generations, was 56. Family size analysis showed that fewer males than females were used, resulting in the observed levels of inbreeding. Average inbreeding coefficient in the Mazandaran native fowls can be regarded to be below critical levels. However, considering the relationship coefficients of individuals is recommended to aid maintaining genetic diversity of Mazandaran native fowls.     

Pedigree analysis and inbreeding depression on growth traits in Brazilian Marchigiana and Bonsmara breeds

The study of population structure by pedigree analysis is useful to identify important circumstances that affect the genetic history of populations. The intensive use of a small number of superior individuals may reduce the genetic diversity of populations. This situation is very common for the beef cattle breeds. Therefore, the objectives of the present study were to analyze the pedigree and possible inbreeding depression on traits of economic interest in the Marchigiana and Bonsmara breeds and to test the inclusion of the individual inbreeding coefficient (F(i)) or individual increases in inbreeding coefficient (ΔF(i)) in the genetic evaluation model for the quantification of inbreeding depression. The complete pedigree file of the Marchigiana breed included 29,411 animals born between 1950 and 2003. For the Bonsmara breed, the pedigree file included 18,695 animals born between 1988 and 2006. Only animals with at least 2 equivalent generations of known pedigree were kept in the analyses of inbreeding effect on birth weight, weaning weight measured at about 205 d, and BW at 14 mo in the Marchigiana breed, and on birth weight, weaning weight, and scrotal circumference measured at 12 mo in the Bonsmara breed. The degree of pedigree knowledge was greater for Marchigiana than for Bonsmara animals. The average generation interval was 7.02 and 3.19 for the Marchigiana and Bonsmara breed, respectively. The average inbreeding coefficient was 1.33% for Marchigiana and 0.26% for Bonsmara. The number of ancestors explaining 50% of the gene pool and effective population size computed via individual increase in coancestry were 13 and 97.79 for Marchigiana and 41 and 54.57 for Bonsmara, respectively. These estimates indicate reduction in genetic variability in both breeds. Inbreeding depression was observed for most of the growth traits. The model including ΔF(i) can be considered more adequate to quantify inbreeding depression. The inclusion of F(i) or ΔF(i) in the genetic evaluation model may not result in better fit to the data. A genetic evaluation with simultaneous estimation of inbreeding depression can be performed in Marchigiana and Bonsmara breeds, providing additional information to producers and breeders.     

Genetic variability in Colombian Creole cattle populations estimated by pedigree information

The genetic structure of 4 Colombian Creole cattle breeds, namely, Coste?o con Cuernos, Blanco Orejinegro (BON), Romosinuano (ROMO), and Sanmartinero (SM), was studied with an analysis of the available pedigree data. The comparison between the effective number of founders (f(e)) and the effective number of ancestors (f(a)) revealed a decrease in the genetic variation that was rather important for the ROMO and San Martinero breeds, which had the lowest f(a)/f(e) ratios (0.34 and 0.53, respectively). All breeds showed similar values for the number of equivalent generations traced, ranging from 3.1 in BON to 4.8 in ROMO. These 2 populations also had the lowest and the highest population sizes, respectively. The lowest average inbreeding coefficient considering the whole pedigree was obtained by BON (0.18%), whereas the highest was attained by ROMO (1.22%). Finally, the percentage of individuals with an inbreeding level greater than 6.25% in the reference population was high, indicating that the existing conservation management strategies could be improved to successfully maintain the genetic variability of these populations.     

Effects of ignoring inbreeding in model-based accuracy for BLUP and SSGBLUP

Model-based accuracy, defined as the theoretical correlation between true and estimated breeding value, can be obtained for each individual as a function of its prediction error variance (PEV) and inbreeding coefficient F, in BLUP, GBLUP and SSGBLUP genetic evaluations. However, for computational convenience, inbreeding is often ignored in two places. First, in the computation of reliability = 1-PEV/(1 + F). Second, in the set-up, using Henderson's rules, of the inverse of the pedigree-based relationship matrix A . Both approximations have an effect in the computation of model-based accuracy and result in wrong values. In this work, first we present a reminder of the theory and extend it to SSGBLUP. Second, we quantify the error of ignoring inbreeding with real data in three scenarios: BLUP evaluation and SSGBLUP in Uruguayan dairy cattle, and BLUP evaluations in a line of rabbit closed for >40 generations with steady increase of inbreeding up to an average of 0.30. We show that ignoring inbreeding in the set-up of the A- inverse is equivalent to assume that non-inbred animals are actually inbred. This results in an increase of apparent PEV that is negligible for dairy cattle but considerable for rabbit. Ignoring inbreeding in reliability = 1-PEV/(1 + F) leads to underestimation of reliability for BLUP evaluations, and this underestimation is very large for rabbit. For SSGBLUP in dairy cattle, it leads to both underestimation and overestimation of reliability, both for genotyped and non-genotyped animals. We strongly recommend to include inbreeding both in the set-up of A- inverse and in the computation of reliability from PEVs.     

MIM: an indirect method to assess inbreeding and coancestry in large incomplete pedigrees of selected dairy cattle

In real data, inbreeding is usually underestimated because of missing pedigree information. A method adapted to the dairy cattle situation is presented to approximate inbreeding when the stored population pedigree is incomplete. Missing parents in incomplete pedigrees were given a dummy identification and assigned to groups (up to nine for a given birth date of progeny). These groups were linked to contemporary reference groups with known parents. An explicit model considered that polygenic breeding values in a censored group were centred on a function of the average breeding value in the corresponding reference group and deviated independently. Inbreeding coefficients were obtained progressively over birth dates starting from founders. For each date considered, the parameters pertaining to its groups were computed using the parameters already obtained from groups belonging to the previous dates. The updating algorithms were given in detail. An indirect method was implemented to expedite mass computations of the relationship coefficients involved (MIM). MIM was compared to Van Raden's (VR) method using simulated populations with 20 overlapping generations and different rates of missing sires and dams. In the situation of random matings, the average inbreeding coefficients by date obtained by MIM were close to true values, whereas they were strongly underestimated by VR. In the situation of assortative matings, MIM gave average inbreeding coefficients moderately underestimated, whereas those of VR's method were still strongly underestimated. The main conclusion of this study adapted to the situation of dairy cattle with incomplete pedigrees was that corrections for inbreeding and coancestry coefficients are more efficient with an explicit appropriate genetic model than without.     

Estimation of inbreeding and effective population size of full‐blood wagyu cattle registered with the American Wagyu Cattle Association

The objective of this research was to examine the population structure of full‐blood (100%) Wagyu cattle registered in the United States with the American Wagyu Association, with the aim of estimating and comparing the levels of inbreeding from both pedigree and genotypic data. A total of 4132 full‐blood Wagyu cattle pedigrees were assessed and used to compute the inbreeding coefficients (F_IT and F_ST) and the effective population size (N_e) from pedigree data for the period 1994 to 2011. In addition to pedigree analysis, 47 full‐blood Wagyu cattle representing eight prominent sire lines in the American Wagyu cattle population were genotyped using the Illumina BovineSNP50 BeadChip. Genotypic data were then used to estimate genomic inbreeding coefficients (F_ROH) by calculating runs of homozygosity. The mean inbreeding coefficient based on the pedigree data was estimated at 4.80%. The effective population size averaged 17 between the years 1994 and 2011 with an increase of 42.9 in 2000 and a drop of 1.8 in 2011. Examination of the runs of homozygosity revealed that the 47 Wagyu cattle from the eight prominent sire lines had a mean genomic inbreeding coefficient (F_ROH) estimated at 9.08% compared to a mean inbreeding coefficient based on pedigree data of 4.8%. These data suggest that the mean genotype inbreeding coefficient of full‐blood Wagyu cattle exceeds the inbreeding coefficient identified by pedigree. Inbreeding has increased slowly at a rate of 0.03% per year over the past 17 years. Wagyu breeders should continue to utilize many sires from divergent lines and consider outcrossing to other breeds to enhance genetic diversity and minimize the adverse effects of inbreeding in Wagyu.     

Pedigree analysis of the Hungarian Thoroughbred population

The aim of the study was to analyse the pedigree information of Thoroughbred horses which were participating in gallop races between 1998 and 2010 in Hungary. Among the 3043 individuals of the reference population there were imported animals from foreign countries (e.g. Germany, England or Ireland) and horses that were born in Hungary. The number of complete generations was 15.64 (varied between 0 for the founders and 25.20), the mean number of full generations was 6.69, and the mean maximum generations were 28.96. The number of founders was 1062, and the effective number of founders was 42. Two hundred and thirty-two founders were born before 1793 (when the stud book of the Thoroughbred breed was closed), therefore these founders are considered as true founders of the breed. These 232 founders were responsible for 88.58% of the gene pool in the reference genome. The significant difference between the number of founders and effective number of founders indicate that the genetic diversity decreased greatly from the founders to the reference population. The number of ancestors was 908 and only 6 of them were responsible for 50% of the genetic diversity in the examined population. The effective number of ancestors was 15.32. From the ratio of the effective number of founders and effective number of ancestors we concluded to a bottleneck effect that characterizes the pedigree under study. Generation interval was more than a year longer for stallions (12.17) than it was for mares (10.64). More than 94% of the individuals in the pedigree were inbred, and the average inbreeding of the population was 9.58%. Considering the changes of the inbreeding status of the examined population 4 large time periods were appointed. The first lasted until 1780, the second period was from 1780 until 1952, the third period was between 1946 and 1998 and the last one was from 1998 until 2008. Rate of inbreeding in the last generation was 0.3%, which forecasts further increase in inbreeding. The effective population size was above 100 in the last 30 generations, proving the genetic diversity did not decrease by a level that would make long-term selection impossible.