荷斯坦奶牛初生重与305天产奶量的相关性分析

为了了解荷斯坦奶牛初生重与305d产奶量的关系,本文收集了新疆呼图壁种牛场1999～2009年351条荷斯坦奶牛的生产性能资料利用SAS软件对荷斯坦奶牛初生重与305d产奶量进行了相关分析。结果表明:荷斯坦奶牛初生重与305d产奶量均呈强正相关,且相关系数极显著(P<0.01);总体水平的母牛初生重与305d产奶量的相关系数最高,确定总体初生重中水平对305d产奶量的回归方程为预测305d产奶量的最优回归方程,方程式y=-10087.4+185.3x;用荷斯坦奶牛总体水平的初生重预测305d产奶量较实测305d产奶量提前很早,为牛场早期选育提供理论依据。     

荷斯坦奶牛体型线性性状对305天产奶量的通径分析

进行荷斯坦奶牛体型线性性状时305 d产奶量的通径分析,建立体型线性性状对305 d产奶量的最优回归方程.随机抽取荷斯坦奶牛395头,测量体高、体斜长、胸围、腹固、管围、尻高、尻宽、腰角宽、乳房深度、后房高度、前房附着、乳头长度、乳头外径等13个体型线性性状,收集395头奶牛305 d产奶量.结果表明:前房附着,乳头外径与305 d产奶量相关极显著(P0.05);体斜长、胸围、尻宽、后房高度和前房附着对305 d产奶量的通径系数达到显著水平(P相似文献   

奶牛外貌性状对305d产奶量的多元回归分析

为了进行奶牛外貌性状对305 d产奶量的多元回归分析,试验选择荷斯坦奶牛180头,其中1~3胎各60头,测定其体高(X_1)、胸宽(X_2)、体深(X_3)、尻角度(X_4)、尻宽(X_5)、后肢侧视(X_6)、蹄角度(X_7)外貌性状,对奶牛305 d产奶量进行多元回归分析。结果表明:尻宽、蹄角度、体深与305 d产奶量的相关系数分别为0.306 5,0.260 7,0.246 8;多元回归方程为Y=2761.00-19.33X_1+12.30X_2+41.46X_3-17.66X_4+55.61X_5+3.51X_6+43.25X_7,达极显著水平(P0.01),但自变量X_1、X_2、X_3、X_4、X_6的偏回归系数未达到显著水平(P0.05);最优回归方程Y=2635.83+39.55X_3+46.26X_5+41.43X_7,回归方程及自变量的偏回归系数均达显著水平(P0.05)。说明奶牛外貌性状对305 d产奶量的最优回归方程的建立能够为提高奶牛生产性能提供思路。     

荷斯坦牛体型线性性状对305d产奶量的通径分析

随机抽取荷斯坦牛395头,测量体高、体斜长、胸围、腹围、管围、尻高、尻宽、腰角宽、乳房深度、后房高度、前房附着、乳头长度、乳头外径等13个体型线性性状,收集395头奶牛305d产奶量,进行荷斯坦奶牛体型线性性状对305d产奶量的通径分析,建立体型线性性状对305d产奶量的最优回归方程.结果显示,前房附着、乳头外径与305d产奶量相关极显著(P<0.01),体斜长、后房高度、乳房深度与305d产奶量的相关系数达到显著水平(P<0.05),其余均不显著(P>0.05);体斜长、胸围、尻宽、后房高度和前房附着对305d产奶量的通径系数达到显著水平(P<0.05),并且以直接影响为主导.以体斜长、胸围、尻宽、后房高度和前房附着建立对305d产奶量的最优回归方程y=7601.7470+33.3901x2-_18.3858x3-97.7271x7+71.9464x10-18.5792x11其拟合精度达到0.95以上.     

宁夏地区荷斯坦牛泌乳曲线拟合及其影响因素分析

本研究收集宁夏地区1997—2018年63个奶牛场16.9万头荷斯坦牛的生产性能测定数据，从个体和群体水平拟合泌乳曲线，旨在探析我国高产奶牛群的泌乳性能特征及其影响因素。使用WOOD不完全伽马模型对奶牛的个体泌乳曲线进行拟合，并获得模型参数a、b、c以及二级参数泌乳持续力、高峰奶量、高峰日和305 d产奶量，进而采用线性模型分析胎次、产犊季节、初产月龄、出生年份和牧场规模等因素对泌乳曲线参数的影响。结果表明，高峰奶量为42.18±8.66 kg（平均值±标准差，下同），高峰日为86.15±42.88 d,305 d产奶量为10 023.98±2 139.89 kg。胎次、产犊季节、初产月龄、出生年份和牧场规模对宁夏奶牛泌乳曲线参数均有极显著影响。头胎牛产奶量极显著低于经产牛，夏季产犊奶牛的产奶量显著低于其他季节，初产月龄为22～24月龄时产奶量最高，牧场规模低于500头与高于500头奶牛产奶量存在极显著差异，高峰奶量与305 d产奶量随出生年份的增加而增加。这些研究结果为规模化牧场精细化管理和群体遗传改良提供了有用信息。     

宁夏荷斯坦奶牛早期生长发育、头胎年龄及对产奶量的影响

通过对宁夏平吉堡奶牛场1997~2003年418头奶牛的资料,研究奶牛早期生长发育、头胎产犊年龄与产奶量的关系,为奶牛的生产和育成牛的初配提供参考资料。1试验材料与方法1.1试验材料试验数据由宁夏平吉堡奶牛场提供,收集了场中1997~2003年418头荷斯坦奶牛的初生重、12月龄和16月龄体重,头胎产犊年龄及第1胎、第2胎和第3胎的产奶量等资料。1.2研究方法选取奶牛产奶量每10 d 1次的测定值,奶牛产奶天数达到305 d(10个月)者取前10个月的奶产量为305 d产奶量,不足10个月者校正为305 d产奶量。通过EXCEL软件估计犊牛初生重、12月龄重和16月龄重,及…     

产犊季节对荷斯坦奶牛产奶量的影响

对宁夏平吉堡奶牛场荷斯坦奶牛4个不同的产犊季节的305d产奶量影响进行了分析。结果表明．在宁夏地区荷斯坦奶牛的产犊季节对奶牛305d产奶量有显著的影响。4月份产犊奶牛的305d产奶量最高,显著高于1、7和10月份产犊奶牛的产奶量,1月份和10月份产犊奶牛产奶量明显高于7月份产犊奶牛产奶量,但1月份年口10月份间没有差异,7月份产犊奶牛305d产奶量最低。     

几种非淀粉多糖酶对肉仔鸡日粮能量的当量调控

选用木聚糖酶(x_1)、β-葡聚糖酶(x_2)、纤维素酶(x_3)和果胶酶(x_4)4种非淀粉多糖(NSP)酶,利用离体消化技术,分别研究它们对肉仔鸡日粮能量的当量调控效应。结果表明,4种NSP酶的添加水平与离体消化能(y)进行S曲线拟合的回归方程分别为:y=10.9542-0.3391/{1 exp[(x1-470.8)/115.5]}(R~2=0.9812),y=10.9453-0.3499/{1 exp[(x_2-336.9)/114.8]}(R~2=0.9851),y=10.8849-0.2733/{1 exp[(x_3-308.0)/88.2]}(R2=0.9805),y=10.8450-0.2236/{1 exp[(x_4-543.5)/104.4]}(R2=0.9875);对日粮能量调控效应的主次顺序为木聚糖酶>β-葡聚糖酶>纤维素酶>果胶酶。     

AA肉鸡生产指标间的相关性分析

为了研究AA肉鸡生产指标间的相关关系,试验采用相关和回归分析的方法,对河南省滑县某养鸡场16.59万只AA肉鸡的周龄(x_1)、全群存栏数(x_2)、全群成活率(x_3)、全群周耗料量(x_4)、全群累计耗料量(x_5)、全群只耗料量(x_6)、全群只累计耗料量(x_7)、全群周末体重(x_8)、全群周增重(x_9)、全群周效率(x_(10))和全群累计效率(x_(11))等生产指标进行了相关系数计算和回归分析。结果表明:全群存栏数(x_2)和全群成活率(x_3)之间呈极显著正相关(P0.01),二者与其他各指标间呈负相关关系,其余各生产指标间均呈正相关关系。生产指标间的回归方程为:x_8=59.536-3.698×10~(-3)x_4+0.098 x_5-15.125 x_7(R~2=0.999 9),x_9=-66.988+134.224 x_1+0.053 x_4-8.408 x_6(R~2=0.995 9),x_(10)=1.217+1.543×10~(-3)x_6+1.507×10~(-3)x_7-2.757×10~(-3)x_8(R~2=0.979 8),x_(11)=-19.009+0.041 x_1+0.199 x_3+2.499×10~(-6)x_5(R~2=0.996 4)。说明这些生产指标间存在不同程度的相关关系,某些生产指标间存在显著的回归关系。     

中国荷斯坦奶牛不同地区、泌乳天数及胎次的产奶量校正系数研究

本研究通过对规模化牧场测定日数据进行分析,旨在估计不同地区305 d校正产奶量对应泌乳天数(DIM)的校正系数与胎次校正系数。利用Wood(不完全伽玛)模型对来自不同温度带9个参考群11 749头荷斯坦奶牛2010－2020年间的683 160条测定日产奶量拟合泌乳曲线,估计泌乳曲线参数,计算头胎牛和经产牛1~305 d泌乳天数对应的校正系数,分别分析参考群和验证群305 d校正产奶量和305 d实际累积奶量的差异;利用SAS 9.2中混合线性模型对1~6胎至少有前5个胎记录的牛估计305 d奶量的胎次效应值,并计算1~6胎各胎次的乘法校正系数;比较传统系数和新系数校正结果的差异。结果表明:①参考群头胎牛和经产牛中,泌乳曲线方程的拟合度R²范围分别为0.4593~0.4913和0.5796~0.6341,泌乳高峰日分别为79~85和53 d,泌乳高峰奶量分别为33.1~34.4和46.0~48.6 kg;②对于参考群,头胎牛和经产牛校正系数分别在泌乳≥90 d和泌乳≥30 d基本趋于一致,头胎牛和经产牛泌乳≥60 d的305 d校正产奶量均趋近于305 d实际累积奶量,奶量差值分别在100和200 kg以内;③对于验证群的305 d校正产奶量,头胎牛泌乳≥150 d和经产牛泌乳≥180 d的泌乳天数校正系数适用性更佳,305 d校正产奶量与305 d实际累积奶量比值高于79%;④1~6胎的胎次校正系数分别为1.2121、1.0380、1.0063、1.0000、1.0220和1.0290;⑤与传统系数相比,新泌乳天数校正系数校正效果更好,头胎牛和经产牛新系数校正的305 d奶量较305 d实际累积奶量相差分别在900和700 kg以内;利用新胎次校正系数,2~4胎产奶量可较为准确地校正到5胎成年当量。本研究结果表明,定期更新305 d校正产奶量的泌乳天数与胎次校正系数,便于准确地将不同泌乳天数、不同胎次状态下泌乳牛的产奶量调整到同一基准上,从而更好地比较奶牛个体泌乳性能的高低,为牧场管理提供参考依据。     

蒿类半灌木牧草质量分析

对１１个蒿类半灌木牧草品种的７个营养指标进行综合分析研究，选出了优质种类．     

Proteome analysis of cashmere

As an analysis of the cashmere proteins by Type IV 2‐DE, ten kinds of components, including three components with molecular mass 42–50 kDa whose expression level increased in the winter, were separated. In analyzing nine components of these ten using a mass spectrometer, the three components of molecular mass 70–120 kDa and pI 5.3 were identified as keratin type II microfibrillar (accession no. KRSHL2 ), keratin 48 k type I microfibrillar component 8c‐1 (accession no. KRSHL1 ) and cytosolic phospholipase A2 (accession no. O77793 ), respectively. The three components whose expression level increased in the winter, were identified as keratin type I microfibrillar 48 kDa component 8C‐1 (accession no. P02534 ) and keratin type I microfibrillar 47.6 kDa (accession no. P25690 ) (pI 5.2/42 kDa), keratin type II microfibrillar component 7C (accession no. P15241 ) and keratin typeII‐sheep (accession no. S34165 ) (pI 5.5/45 kDa), and the keratin type II microfibrillar component 5 (accession no. P25691 ) (pI 5.8–6.0/45 kDa), respectively. The three components of less than 17 kDa were identified as hair keratin type II intermediate filament (accession no. CAA51836 ) (pI 5.2) and keratin high‐sulfur matrix protein IIIB2 (accession no. P02447 ) with a different isoelectric point (pI 5.4 and 5.9), respectively.     

Genetic analysis of Trichinella populations by 'cold' single-strand conformation polymorphism analysis

A non-isotopic single-strand conformation polymorphism ('cold' SSCP) technique has been assessed for the analysis of sequence variability in the expansion segment 5 (ES5) of domain IV and the D3 domain of nuclear ribosomal DNA within and/or among isolates and individual muscle (first-stage) larvae representing all currently recognized species/genotypes of Trichinella. Data are consistent with the ability of cold SSCP to identify intra-specific as well as inter-specific variability among Trichinella genotypes. The cold SSCP approach should be applicable to a range of other genetic markers for comparative studies of Trichinella populations globally.     

Gait analysis of poultry

Lameness is a major problem in the UK poultry industry, however, relatively few objective studies have been undertaken into the biomechanics of normal walking in these birds. In this study, the use of a pedobarograph as a novel method of gait analysis in poultry was investigated. Unlike most systems, the pedobarograph has a recording surface with a high degree of spatial resolution, allowing pressure patterns to be established for various regions of the foot. The highest pressures were found to act on the medial toe (149·4–218 kN m⁻²) and back toe (146·1–195-· kN m⁻²). The metatarsal pad, a region often associated with lesions, was subject to lower pressures (16·3–131·2 kN m⁻²). Maximum net forces of 116–145 per cent of bodyweight were found during normal walking, an order of the same magnitude as human bipeds. Routine spatial parameters were also measured, allowing further characterisation of the gait patterns.     

多花黑麦草农艺性状变异及产量通径分析

多花黑麦草(Lolium multiflorum)作为我国南方种植面积最大的一年生禾本科牧草,在现代草牧业建设中发挥着重要作用。本研究以13份多花黑麦草栽培材料为研究对象,选取生长发育中关键的3个时期进行农艺性状的测定,以此探讨影响多花黑麦草产量的主要决定因子。结果表明,供试多花黑麦草材料形态性状具有丰富的遗传多样性,变异系数在4.37%~27.91%,其中单株鲜重与花序宽、节间数、分蘖数和株幅等极显著相关(P0.01),单株干重与自然高度、拉直高度、节间长、旗叶长、茎粗、倒二叶宽和旗叶宽等极显著相关。通过主成分分析、回归分析和通径分析表明,对单株鲜重直接影响最大的综合因子为"株型因子",具体由分蘖数、株幅等控制株型的形态性状指标表达;对单株干重的直接影响最大的综合因子为"叶形因子",具体表达为倒二叶长宽和旗叶长宽的不同。     

Computer image analysis traits of cross-sectioned dry-cured hams: a genetic analysis

The aims of this study were to estimate genetic parameters of image analysis traits of cross-sectioned dry-cured hams and carcass weight (CW) and to investigate effects of some nongenetic sources of variation on these traits. Computer image analysis (CIA) had been carried out for digital images of the cross-section of 1,319 San Daniele dry-cured hams. The cross-sectional area (SA, cm(2)); the average thickness of subcutaneous fat (FT, cm); and the proportions of lean (LA, %), fat-eye (FEA, %), and subcutaneous fat area (SCF, %) to SA, and of biceps femoris (BFA, %) and semitendinosus muscle area (STA, %) to LA were recorded. Bivariate analyses were carried out for pairs of traits for estimation of genetic parameters using Bayesian methodology and linear models. Linear models included the nongenetic effects of slaughter groups and sex and the additive genetic effects of pigs and their ancestors (1,888 animals). Variation of FEA was nearly 4-fold that of SA and LA. Variation of CIA traits due to sex effect was not large, whereas slaughter group effects were relevant sources of variation for all traits. For all traits, with the exception of FEA, the posterior probability for the true heritability being greater than 0.1, was greater than 0.95. Point estimates of heritabilities for FT and SCF were 0.42 and 0.51, respectively. Heritability estimates for FEA, LA, BFA, and STA were 0.13, 0.44, 0.44, and 0.36, respectively. The genetic correlations between CW and CIA traits were positive and large for SA (0.86), positive and moderate for FT, FEA, and STA (0.47, 0.40, and 0.45, respectively) and negative with LA (-0.28). Although FEA, FT, and SCF were all measures of the extent of fat deposition in the ham, the genetic correlations between FT or SCF and FEA were very low. A very large estimate (0.74) was obtained for the genetic relationship between SA and FEA, suggesting that reduction of ham roundness through selective breeding would be beneficial for decreasing FEA. On the basis of the estimated parameters, genetic selection is expected to be effective in changing size of fatty and lean areas of the cross-section of dry-cured hams. Causes related to the abnormal development of the fat-eye depot remain unknown, but this study provided evidence that influences of polygenic effects on phenotypic variation of FEA are limited.