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Genetic evaluation using random regression models with different covariance functions for test‐day milk yield in an admixture population of Thailand goats 下载免费PDF全文
Mongkol Thepparat Wuttigrai Boonkum Monchai Duangjinda Sornthep Tumwasorn Sansak Nakavisut Thumrong Thongchumroon 《Animal Science Journal》2015,86(7):655-660
The objectives of this study were to compare covariance functions (CF) and estimate the heritability of milk yield from test‐day records among exotic (Saanen, Anglo‐Nubian, Toggenburg and Alpine) and crossbred goats (Thai native and exotic breed), using a random regression model. A total of 1472 records of test‐day milk yield were used, collected from 112 does between 2003 and 2006. CF of the study were Wilmink function, second‐ and third‐order Legendre polynomials, and linear splines 4 knots located at 5, 25, 90 and 155 days in milk (SP25–90) and 5, 35, 95 and 155 of days in milk (SP35–95). Variance components were estimated by restricted maximum likelihood method (REML). Goodness of fit, Akaike information criterion (AIC), percentage of squared bias (PSB), mean square error (MSE), and empirical correlation (RHO) between the observed and predicted values were used to compare models. The results showed that CF had an impact on (co)variance estimation in random regression models (RRM). The RRM with splines 4 knots located at 5, 25, 90 and 155 of days in milk had the lowest AIC, PSB and MSE, and the highest RHO. The heritability estimated throughout lactation obtained with this model ranged from 0.13 to 0.23. 相似文献
33.
Genetic analysis of fat‐to‐protein ratio,milk yield and somatic cell score of Holstein cows in Japan in the first three lactations by using a random regression model 下载免费PDF全文
Akiko Nishiura Osamu Sasaki Mitsuo Aihara Hisato Takeda Masahiro Satoh 《Animal Science Journal》2015,86(12):961-969
We estimated the genetic parameters of fat‐to‐protein ratio (FPR) and the genetic correlations between FPR and milk yield or somatic cell score in the first three lactations in dairy cows. Data included 3 079 517 test‐day records of 201 138 Holstein cows in Japan from 2006 to 2011. Genetic parameters were estimated with a multiple‐trait random regression model in which the records within and between parities were treated as separate traits. The phenotypic values of FPR increased soon after parturition and peaked at 10 to 20 days in milk, then decreased slowly in mid‐ and late lactation. Heritability estimates for FPR yielded moderate values. Genetic correlations of FPR among parities were low in early lactation. Genetic correlations between FPR and milk yield were positive and low in early lactation, but only in the first lactation. Genetic correlations between FPR and somatic cell score were positive in early lactation and decreased to become negative in mid‐ to late lactation. By using these results for genetic evaluation it should be possible to improve energy balance in dairy cows. 相似文献
34.
天然草地合理载畜量是反映草地合理利用强度的基本单位。为提高草地合理载畜量的划分精度,根据“极大似然逼近原理”,创建了异质因子控制下的“线性回归+区域化值残差修正”数据空间化方法。以全国草地资源调查汇总数据中县域理论载畜量和1∶400万中国草地资源图为基础数据,采用分省控制构建了理论载畜量与植被类型-生产力异质植被斑块的线性回归模型,其判定系数由全国模型下的0.867提高到0.937,拟合优势度较高,所获得的中国公里格网草地合理载畜量分布图空间化精度也较高。中国公里格网草地合理载畜量分布图不仅表明了不同类草地因生产力的不同有不同的放牧要求,也体现了不同环境条件下草地载畜能力的差别,有效反映了单位面积内草地植被载畜-生产力水平,为生态治理和草地资源保育工作中合理制定草地利用强度提供了理论参考。 相似文献
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红外光谱结合多元线性回归法快速测定木塑复合材料中木粉含量 总被引:1,自引:0,他引:1
采用KBr压片法对杉木/聚丙烯(PP)复合材料样品进行了红外光谱分析,确定杉木特征吸收谱带为1740~1730、1610~1590、1270~1260、1060~1050以及1040~1030 cm-1,以PP在1377 cm-1处吸收强度(I)为内标,对木塑复合材料(WPC)中木粉含量和杉木特征峰相对吸收强度进行相关性分析,并采用逐步多元线性回归法建立木粉含量与相对峰强间的多元线性回归方程。结果表明,选取I(1060-1050)/I1377、I(1270-1260)/I1377为回归变量建立的二元线性回归方程和以I(1060-1050)/I1377、I(1040-1030)/I1377及I(1270-1260)/I1377为回归变量建立的三元线性回归方程,具有较高的预测精度。木粉含量的预测值和参照值之间具有强烈的相关性,校正决定系数(R2c)超过0.98,验证决定系数(R2p)超过0.96。外部验证结果表明,线性回归方程预测准确性较高,预测相对偏差范围为0.9%至7.4%,其中三元线性回归方程预测准确性稍好于二元线性回归方程。 相似文献
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以福建省顺昌县的杉木纯林、毛竹纯林、杉木马尾松混交林、杉木阔叶混交林、阔叶林等5块样地为对象,从结构性、功能性和抗干扰性等3个方面出发,筛选出15个指标,并利用主成分分析(PCA)实现了研究区森林健康评价。结果显示:福建省顺昌县杉木纯林、毛竹纯林、杉木马尾松混交林、杉木阔叶混交林、阔叶林等5块样地的森林健康综合指数值依次为-0.27、-0.25、0.35、0.53和-0.01,从优到次的排名为:杉木阔叶混交林、杉木马尾松混交林、阔叶林、毛竹纯林、杉木纯林。 相似文献
39.
气候变化适应及其影响因素研究——山东胶州湾地区居民的实证分析 总被引:1,自引:0,他引:1
为探索气候变化感知在适应决策过程中的作用机理,本研究以深度访谈数据为基础,基于“感知-适应”分析框架,采用二元Probit模型和泊松回归模型,分析胶州湾地区居民气候变化适应决策和适应选择的影响因素。研究表明,胶州湾地区绝大多数居民已经感知到气候变化,半数以上居民采取了一定的适应措施,大多数居民对适应措施效果的感到满意。居民采取适应措施介于0-4项,平均为1.07项,适应措施的普及率和多样化仍有提升空间。影响胶州湾地区居民气候变化适应决策与适应选择的主要因素存在一定差异性,但“居民对气候变化的感知”不论是对适应决策还是对适应选择的影响都较大,其中又以“对降水变化的感知”和“对气象灾害损失的感知”最为显著。 相似文献
40.
Zohreh Sankian Sanaz Khosravi Yi‐Oh Kim Sang‐Min Lee 《Journal of the World Aquaculture Society》2019,50(1):34-41
An 8‐week feeding trial was conducted to investigate the dietary protein requirement of juvenile mandarin fish, Siniperca scherzeri, a demersal freshwater piscivore with high commercial value in East Asia. Five isolipidic (100 g/kg) and isoenergetic (20 MJ/kg) practical diets were formulated to contain graded levels of 450, 500, 550, 600, and 650 g/kg crude protein, using mackerel fishmeal as the sole source of protein. Each of the five test diets was fed to visual satiety to triplicate groups of fish (initial mean body weight ± SE; 20.1 ± 0.2 g) reared in a recirculating freshwater system over the experimental period. Fish growth performance in terms of weight gain tended to improve with increasing dietary protein level, and the highest values were observed in those fish fed the 600–650 g/kg diets. Feed intake significantly declined as the protein content of the diet increased. Feed efficiency and protein retention tended to increase with increasing dietary protein levels, from 450 to 600 g/kg, and then declined when dietary protein content further increased to 650 g/kg. A similar trend was also found for the protein efficiency ratio, although the observed changes did not reach statistical significance. Whole‐body composition and plasma biochemical parameters were not significantly affected by the dietary protein content. Based on these findings and a broken‐line model of growth, 614.4 g/kg seems to be the proper amount of protein in a practical diet for >20 g mandarin fish. 相似文献