Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/25447
標題: 台灣土雞產蛋性狀遺傳變異之研究
A Study on the Genetic Variability of Egg Production Traits in Taiwan Country Chicken
作者: 戴珮珊
Tai, Pei-San
關鍵字: Taiwan Country Chicken;台灣土雞;Clutch;Genetic Variability;產蛋週期;遺傳變異
出版社: 畜產學系
摘要: 
繁殖性能為肉種雞重要的經濟性狀之一,一般而言台灣土雞的產蛋表現較差,導致種雞在繁殖上有嚴重的問題。對於家禽產蛋能力之遺傳改進,蛋雞應用產蛋週期或休產期性狀為選拔標準,同樣也獲得總產蛋數顯著之遺傳改進。且產蛋週期與休產期性狀的收集並不困難。所以本研究將影響總產蛋數的因素分成產蛋週期和休產期二方面,分析性狀包括初產日齡、初產至40週齡總產蛋數及26至40週齡隻日產蛋率、產蛋週期性狀、休產期性狀。應用上述性狀來探討台灣土雞不同品系間產蛋之變異。使用國立中興大學選育土雞族群,父系(B、S品系)和母系(D、L2品系),連續五個選拔世代的產蛋資料。先將非常態分布性狀包括平均產蛋週期長度、最大產蛋週期長度、平均休產期長度和最大休產期長度,以Box-Cox方法進行常態轉型。再利用VCE4軟體應用動物模式下限制最大似然估計法,分析各性狀之遺傳參數。研究結果如下:
一、各品系產蛋性狀之比較
產蛋表現最好的L2品系,至40週齡總產蛋數為71.7枚,產蛋持續性佳,產蛋週期長;產蛋表現次之的D品系,至40週齡總產蛋數為70.7枚,初產日齡最早157.2天,達產蛋高峰最快,產蛋週期數和休產期數多;S品系的產蛋表現居於第三位,至40週齡總產蛋數為59.4枚,休產期長;產蛋表現最差的B品系,至40週齡總產蛋數為50.7枚,初產日齡最晚175.5天,最慢達產蛋高峰,產蛋週期短。
二、Box-Cox方法之常態轉型
非常態分布性狀經Box-Cox方法轉型後,其偏態和峰度係數更接近於零,性狀分布更接近於常態分布。相同性狀經常態轉型後的遺傳率較轉型前的為高。
三、產蛋性狀遺傳參數估計
在遺傳率方面,父系以休產期性狀而母系以產蛋週期性狀的遺傳率最高,且較總產蛋數的遺傳率大。在遺傳相關方面,四個品系皆以休產期性狀與總產蛋數間之遺傳相關較高。在比較同品系內以產蛋週期或休產期性狀進行間接選拔,對改進總產蛋數方面,父系以休產期性狀而母系以產蛋週期性狀之選拔效益較好。
為排除影響土雞產蛋變異之其他因素,可能為藾菢、疾病或緊迫等,以產蛋紀錄中休產期長度大於等於七天來表示。父系產蛋紀錄扣除較長休產期長度的部份產蛋紀錄後,使休產期性狀及隻日產蛋率之遺傳率不變或下降;母系扣除後使休產期性狀及隻日產蛋率之遺傳率不變或增加。

Reproductive performance was one of the important economic traits in the breeder chickens. In general, Taiwan country chicken has showed a lower egg production as a result of a serious problem for egg production in the breeder. Selection for increase clutch length has achieved a significant improvement for egg production in layers. The purposes of this study were to estimate the genetic correlations between clutch traits and egg production in Taiwan country chicken. The data set was from the National Chung-Hsing University a long-term selection experiment, four strains B, S, D, and L2 that were from the same base population. Daily egg production and pedigree records of the last five generations were used to analyze. In order to satisfy the classical hypothesis for describing traits with polygenetic inheritance via a linear model with normal error, the Box-Cox transformation was used to normalize trait distribution. Variance and covariance components were estimated using VCE package.
1.Compare with egg production traits among the four strains
Total egg numbers to 40 wks of age was 71.7, 70.7, 59.4, and 50.7 for the L2, D, S and B strains, respectively. L2 strain had the longest average clutch length (4.07). S strain had the longest average pause length (4.42). The age at first egg is shorter in D strain (157.2), and B strain had the longest (175.5).
2.Box-Cox transformation
The coefficient of skewness and kurtosiss of non-normally distributed traits after the Box-Cox transformation were close to zero. After normality, the heritabilities of the most of traits were increased.
3.Estimation of genetic parameters for egg production traits
The results in comparison with heritability of egg production in Taiwan Country Chicken, in sire strains (B, S strain), the heritabilities of pause traits were higher than heritability of total egg number, in dam strains (D, L2 strain), the heritabilities of clutch traits were higher than heritability of total egg number. Genetic correlations between pause traits and the number of eggs laid to 40 weeks of age were higher among the four strains. Compare to egg number with the related selection traits, the pause traits were more relative efficiency in sire strains, and the clutch traits were more relative efficiency in dam strains.
In sire strains, heritabilities of pause traits deleting periods without laying egg for more than seven days were lower than those of undelete. In contrast, the heritabilities of pause traits exhibited a higher value in dam strains.
URI: http://hdl.handle.net/11455/25447
Appears in Collections:動物科學系

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