Growth Analysis Of Crossbred Filial-generation Two Of Boer×Xuhuai White Goats

With the development of goat meat industry in china, Boer goats have been introduced into our country recently. The growth rate of the native goat breeds was improved by boer buck crossing with native does, which presents the heterosis. The cross offsprings especially the filial generation two (F2) were bigger in body size and grew more fast than the native goat. At present, generation F2 goats played an important role in meat industry all over the country. It was necessary to select individual with excellent traits by analysis of generation F2 growth for farther crossing. On the other hand, the reasonable management of raising cross kids must depend on the knowledge of growth and development of generation F2. The aims of this study are: (1) to set up a growth model of generation F2 by analyzing the growth and development of their body weight and measurements; (2) to analyze the factors that affect the growth and development of body weight and measurements for generation F2; (3)to analyze the principal component on body weight and measurements of filial-generation kids (Boer Boer Xuhuai White goat) 1. The establishment of growth models of body weight and measurements in generation F2The data of the studies came from Jiangpu Goat Farm under Jiangsu Nihua Company in Agriculture, Industry and Trade Development, which included body weight, body height, body length, body slanting length, chest measurement at the age of 0, 1, 3, 6, 8, 12 month of the generation F2. The records were from 459 does of generation F1 in 2000 and 2002.Three arithmetic models including Mitschetrlich, Gompertz and Logistic were used tofit the growth curves of body weight and measurements of BoerxXuhuai White generation F2 goats. The comparison results indicated that the Mitschetrlich model was the best in all models. The growth parameters were estimated by Mitschetrlich model. Growth spinode and spinodal age of body weight, body height, body length, body slanting length, chest measurement were 10.69kg 19.89cm31.52cm 33.21cm 22.32cm and 111.30d 115.30d 105.58d 104.43d 106.96d respectively. The maximum of daily gain were 0.05 kg/d 0.24cm/d 0.31 cm/d 0.32 cm/d 0.25 cm/d respectively. Instantaneous comparative growth rate were 0.1333 0.3661 0.2984 0.2894 0.3375 respectively. The maximal weight and measurements were 29.0519kg 54.08cm 85.67cm 90.27cm 60.68cm respectively. The results show that the estimated value of growth spinode in body measurements can not be applied to the practice, though the models represent the growth rule. So if the growth models can be used in body measurements should be discussed.2. The factors that affect the growth and development of body weight and measurements in generation F2 goatsThe factors that affect the growth and development of body weight and measurements of generation F2 were analyzed according to sex, sib size, buck effect, and birth years. The results presented that sex, sib size and birth years significantly affect the growth and development of animals. Bucks grew faster than does. The single grew faster than twins and triplets, but the difference between twins and triplets was not significant and decreased gradually. Growth rate in 2001 was higher than that in 2000, which showed the effect of selection breeding.3. Analysis of the principal component on body weight and measurements of filial-generation of goatsThe five traits including body weigh and measurements of 190 filial-generation kids(Boer Xuhuai White goat) were studied by principal component analysis at the age of0, 1, 4, 6 monthes. The result suggested that there were different correlation coefficientsamong the traits and the variation of the five traits were well-distributed in the first principal component at different ages. The second principal component mainly reflected the variation of body measurements. The change of kid growth could be seen from the difference in the principal components at different ages. The method of principal component analysis that evaluate body weigh and measurements of kids was scientific and simple. It will p...