Empirical Growth Curve Estimation Using Sigmoid Sub-functions that Adjust Seasonal Compensatory Growth for Male Body Weight of Thoroughbred Horses

Thoroughbred horses are seasonal mating animals, raised in northern regions or countries. Foals born yearly in spring generally show a typical seasonal compensatory growth pattern, in which their growth rate declines in the first winter and increases in the next spring. In this study, a new empirical adjustment approach is proposed to adjust for this compensatory growth when growth curve equations are estimated, by using 1,633 male body weights of Thoroughbreds as an illustrating example. Based on general Richards growth curve equation, a new growth curve equation was developed and fit to the weight-age data. The new growth curve equation had a sigmoid sub-function that can adjust the compensatory growth, combined with the Richards biological parameter responsible for the maturity of animals. The unknown parameters included in the equations were estimated by SAS NLMIXED procedure. The goodness of fit was examined by using Akaike’s Information Criterion (AIC). The AIC values decreased from 13,053 (general Richards equation) to 12,794 (the newly developed equation), indicating the better fit of the new equation to the weight-age data. The shape of the growth curve was improved during the period of compensatory growth. The proposed method is one of the useful approaches for adjusting seasonal compensatory growth in growth curve estimations for Thoroughbreds, and for their management during the compensatory period. Based on this approach, the optimal growth curve equations can be estimated also for female body weight of Thoroughbreds or other growth traits affected by seasonal compensatory growth.     

Empirical Percentile Growth Curves with Z-scores Considering Seasonal Compensatory Growths for Japanese Thoroughbred Horses

Percentile growth curves are often used as a clinical indicator to evaluate variations of children’s growth status. In this study, we propose empirical percentile growth curves using Z-scores adapted for Japanese Thoroughbred horses, with considerations of the seasonal compensatory growth that is a typical characteristic of seasonal breeding animals. We previously developed new growth curve equations for Japanese Thoroughbreds adjusting for compensatory growth. Individual horses and residual effects were included as random effects in the growth curve equation model and their variance components were estimated. Based on the Z-scores of the estimated variance components, empirical percentile growth curves were constructed. A total of 5,594 and 5,680 body weight and age measurements of male and female Thoroughbreds, respectively, and 3,770 withers height and age measurements were used in the analyses. The developed empirical percentile growth curves using Z-scores are computationally feasible and useful for monitoring individual growth parameters of body weight and withers height of young Thoroughbred horses, especially during compensatory growth periods.     

Bodyweights and growth rates of spring- and autumn-born Thoroughbred horses raised on pasture

AIM: To examine the growth of spring- and autumn-born Thoroughbred foals raised on pasture.

METHODS: Bodyweight and growth rates were measured in pasture-raised Thoroughbred horses, born in either spring (n=56) or autumn (n=7), from birth to approximately 13 and 17 months of age.

RESULTS: Birthweight tended to be lower in autumn- than spring-born foals (54.4, SD 7.92 kg vs 57.3, SD 5.90 kg; p=0.08). Between birth and 6 months of age, there was no difference in growth rate at equivalent ages between horses born in spring and autumn. Spring-born horses, which were weaned in the autumn, had lower post-weaning growth rates than autumn-born horses that were weaned in the spring. At time of the late yearling sales (March–April) in the Southern Hemisphere, unadjusted mean bodyweights of autumn-born horses (379.3, SD 24.8 kg) were lower (p=0.017) than those of the spring-born horses (437.2, SD 35.3 kg), although values in the autumn-born horses were all within two standard deviations (SD) of the mean of the spring-born animals. When adjusted for the covariates of birthweight and gender, the difference between spring- and autumn-born horses at that time was not significant (p=0.25).

CONCLUSIONS AND CLINICAL RELEVANCE: Some autumn-born foals could be marketed for late yearling sales in the Southern Hemisphere, on the basis of bodyweight. Furthermore, they might also be competitive in the Northern Hemisphere industry (sales or racing), as they would be competing against horses of the same official age.     

新疆褐牛体重生长曲线的研究

试验旨在对新疆褐牛体尺指标进行分析,研究其生长发育规律并揭示各性状间的相互关系。选取2010～2015年间伊犁昭苏地区8～20月龄新疆褐牛公牛,共计2 794头,测定其体重、体高、体斜长、胸围及管围指标数据,绘制生长发育曲线,并对新疆褐牛2010～2015年体尺测定数据进行相关性回归分析及验证。结果表明,新疆褐牛公牛的体长在14～15月龄间增长较快;体重与所测4项体尺指标间均呈正相关关系,且均为极显著（P<0.01）,其中与胸围相关性系数最高（r=0.796）,与体长的相关性系数最低（r=0.163）;获得新疆褐牛公牛体重回归预测方程：Y=-564.607-0.174X₁+2.441X₂+3.497X₃-1.086X₄,经过验证回归方程具有统计学意义,为新疆褐牛的选育提供数据基础。     

山西白猪的微卫星标记与其体重、体尺性状的关联分析

 采用单变量动物模型分析了21个微卫星标记对山西白猪初生重、断奶重、6月龄体重、体长、体高、胸围和活体背膘厚等7个性状的影响。结果表明,S0227和S0218标记对6月龄活体背膘厚有显著影响（P<0.05）。在S0227座位上,杂合子AB型个体的6月龄背膘厚最薄;在S0218座位上,BB和CC型个体的背膘最薄。S0101标记对6月龄体高有显著影响（P<0.05）,对6月龄体重的影响也接近显著水平（P=0.0854）。在S0101座位上, CC型个体的6月龄体重最大,显著高于AB型个体,而与其他类型差异不显著;BC型个体的体高最高,显著高于AB型,而与其他类型差异不显著。     

Study on Body Weight Growth Curve in Xinjiang Brown Cattle

The experiment was designed to investigate growth and development pattern and reveal the correlation of each traits of Xinjiang Brown cattle according to analysis body index data.2 794 Xinjiang Brown bulls were selected to measure body index and draw the growth curve of body weight during year 2010 to 2015 in Yili Zhaosu region.The body index was composed by body weight,body height,body length,chest circumference and canon circumference.All measured data were analyzed and validated underwent correlation and regression analysis.The results showed that body length of Xinjiang Brown bulls were grow fastely at the age 14 to 15 months;Body weight was extremely significantly positive correlated with other four measured body index (P<0.01).Of them,the correlation coefficient with chest circumference was the highest (r=0.796),and the lowest was with body length (r=0.163).The body weight regression estimate formula of Xinjiang Brown bulls was Y=-564.607-0.174X₁+2.441X₂+3.497X₃-1.086X₄,and the validation result implied this formula was statistical significance.Our work offers a good data basic for genetics selection and breeding of Xinjiang Brown cattle.     

康县太平鸡早期生长曲线拟合及体重与体尺相关性分析

为研究太平鸡早期生长发育规律,提高品种选育效果,采用Logistic、Von Bertalanffy、Gompertz三种非线性生长模型对其体重进行拟合,并对13周龄的体重与体尺进行相关性分析。结果表明：Gompertz模型对太平鸡0～15周龄体重的拟合效果最佳,拟合所得的太平公、母鸡的拐点周龄分别为7.08周、6.84周,拐点体重分别为572.24 g、482.74 g,成熟体重分别为1 555.34 g、1 312.09 g;13周龄太平鸡体重与体尺之间存在不同程度的相关性,公鸡的体重与体斜长、龙骨长、胫长、胫围、骨盆宽呈极显著正相关（P<0.01）;母鸡的体重与龙骨长、胫长、胫围、胸围、骨盆宽呈极显著正相关（P<0.01）。     

朝鲜鹌鹑屠宰性能及其与体重的相关性分析

选择7日龄的朝鲜鹌鹑300只(公、母各半),在相同管理条件下饲养至38日龄,每周定期称重,并在38日龄时随机抽取150只(公、母各半)进行屠宰,系统分析公、母鹑的体重及主要屠宰性能指标。结果表明,除10日龄体重外,朝鲜母鹌鹑的体重均极显著地高于公鹌鹑(P<0.01);母鹑的宰前重、放血重、屠体重、半净膛重、全净膛重、半净膛率、胸肌率、腿肌重和胸肌重显著高于公鹑(P<0.05或P<0.01);相关分析显示,公、母鹑不同日龄体重间均呈极显著的正相关(P<0.01);除母鹑的半净膛率、全净膛率、胸肌重、腿肌重及公鹑的屠宰率、半净膛率、胸肌重、腿肌重外,不同日龄体重与其他屠宰性状间多呈显著的正相关(P<0.05或P<0.01)。     

乌苏里貉生长发育规律研究及其生长曲线模型拟合

选取60只分窝乌苏里仔貉,按出生窝别、出生时间、性别、体重分为4组,生长期和冬毛期分别饲喂4种不同的试验E／粮,研究其生长发育规律,拟合其体重和体长生长模型。结果表明：乌苏里貉周平均日增重在8～12周龄和18～24周龄有2个高峰期（分别为40g／d和50g／d）,体长生长速度在9～14周龄和20～22周龄有2个高峰期（分别为0．3cm／d和0．2cm／d）;体重和体长适宜生长曲线方程分别为：Y=241．47＋42．242X＋19．041X^2-0．399X^3（R^2=0．994）,Y=9．517＋3．374X-0．067X^2（R^2=0．992）。     

河南大尾寒羊体重生长特性的研究

应用VonBertalanffy、Gompertz、logistic、幂函数非线性生长模型对河南大尾寒羊的生长进行了拟合,Gom-pertz和logistic方程能很好地反映河南大尾寒羊的生长特点。本品种具有较好的早熟性;粗放的饲养管理可导致羔羊断奶后体增重急剧减慢;利用回归方程计算的母羊适宜初配日龄为211￣240d。     

新疆也木勒白羊羔羊生长发育规律及其与体尺的相关性研究

试验对0~120日龄新疆也木勒白羊羔羊体尺指标、体重生长发育规律进行了分析,旨在为也木勒白羊品种选育提供理论依据。选择222只也木勒白羊初生羔羊,每30 d对其体尺、体重进行测量,直至120日龄。结果显示,也木勒白羊公、母羔早期各月龄体重、体尺累积增长差异极显著（P<0.01）,公羔生长发育较母羔快,公、母羔30~60日龄生长速度最快,30~60日龄公羔平均日增重（ADG）较母羔多6.8 g/d;体尺指标分析结果显示,体长、体高、管围、脂臀宽和脂臀厚在0~30日龄增长最快,胸围和脂臀长在30~60日龄增长最快,公、母羔脂臀长指标在90~120日龄差异明显;120日龄断奶羔羊体尺与体重表型相关性分析结果显示,羔羊胸围与体重的相关系数最大,脂臀长与体重的相关系数最小。通径分析结果显示,羔羊胸围对体重的直接作用较大,体高、体长、脂臀长和脂臀宽主要通过间接作用影响体重。公羔管围对体重的直接作用大于间接作用,母羔管围对体重的间接作用大于直接作用。     

闽南火鸡生长特性的研究

本试验观测了闽南火鸡的生长发育特性。应用三种非线性生长模型对闽南公，母火鸡生长曲线进行拟合，估测生长参数，以Von Bertalanffy模型的拟合度最高，公、母火鸡拟合度分别为0．999和0．996，说明此模型较好地反映了闽南火鸡的生长特点，结果表明，公火鸡生长速度明显快于母火鸡，公、母火鸡最大日增重分别为32．99g和19．34g，从60日龄开始公、母火鸡体重差异显著，210日龄公，母火鸡体重分别为5746.5g和2964．3g。成年火鸡体尺性状与体重经相关分析表明，公火鸡的体斜长，胸深，胸宽，龙骨长和体重呈极显著正相关；而母火鸡的体斜长，胸深，胸宽，骨盆宽，胫长和体重呈极显著正相关，以上结果为闽南火鸡的选择育和生长预测提供了科学依据。     

不同猪种ADIPOQ基因外显子2多态性及其与山西白猪体重和体尺性状的关联分析

本研究旨在检测猪脂联素（adiponectin,ADIPOQ）基因外显子2的多态性,并分析其对山西白猪体重和体尺性状的影响。采用PCR-SSCP技术检测了长白猪、大白猪、杜洛克猪、山西白猪、山西黑猪和马身猪6个猪种392个个体ADIPOQ基因外显子2的多态性,并采用GLM程序分析了ADIPOQ基因外显子2多态性与山西白猪体重和体尺性状的关联性。结果显示,在ADIPOQ基因外显子2的89 bp处检测到G→A错义突变,引起缬氨酸（Val）向异亮氨酸（Ile）的转变。ADIPOQ基因外显子2存在3种基因型：AA、AB、BB,2个等位基因：A和B。杜洛克猪中只有BB基因型,长白猪、大白猪、山西白猪和山西黑猪中BB基因型为优势基因型,马身猪中AA基因型频率最高。在引入品种长白猪、大白猪和杜洛克猪中B等位基因为优势等位基因,基因频率分别为0.96、0.96和1.00;在地方品种马身猪中A等位基因频率（0.52）略高于B等位基因（0.48）;在培育品种山西白猪和山西黑猪中B等位基因频率分别为0.76和0.78,介于引入猪种和地方品种之间。基因型频率分布在马身猪、山西白猪和山西黑猪之间无显著差异（P>0.05）,杜洛克猪与长白猪、大白猪间差异均不显著（P>0.05）,而长白猪和大白猪间差异显著（P<0.05）,任意一个引入品种与马身猪、山西白猪和山西黑猪之间的差异均达到极显著水平（P<0.01）。ADIPOQ基因外显子2多态性对断奶重有显著影响,其中BB基因型个体28日龄断奶重显著高于AA和AB基因型（P<0.05）,AA和AB基因型间无显著差异（P>0.05）,但对其他性状无显著影响,说明该位点只在个体发育早期阶段起作用。     

仙居鸡体重生长模型拟合研究

本研究运用Logistic、Gompertz和Von Bertalanffy3种非线性生长模型对0～12周龄仙居鸡生长发育进行了拟合.研究表明,3种曲线的均能较好的拟合仙居鸡的生长发育过程,拟合度均在0.99以上,但是其中Gompenz拟合结果更符合生产实际,较适用于仙居鸡的生长拟合.通过适宜生长曲线的拟合能够较好地判断掌握鸡群的生长特性,为科学的饲养管理提供可靠的理论依据.