Comparison Of Early Growth And Development Rules And Analysis Of Influencing Factors Of Different Sheep Hybrid Combinations

Hybridization is a variety improvement mode widely used in production and breeding,which can make the genes of two parents cooperate together to create new and more favorable genotypes,so as to enrich the genetic types of new varieties.Through hybridization,we can make full use of the complementarity of characters among varieties,combine the characteristics of different varieties,create the characteristics that parents did not have originally,and improve the productivity of offspring.As a traditional and ancient sheep breed in Xinjiang,Kazak sheep has the characteristics of rough feeding resistance,strong disease resistance,good adaptability and fast growth and development in the early stage,but it also has the defects of low meat production performance and large tail fat.With the change of current market and consumer demand,the above defects have become increasingly prominent,which has become an important factor restricting the improvement of Kazakh sheep breeding efficiency,and genetic improvement is urgently needed.Texel Sheep is famous for its excellent meat production performance.It is one of the terminal male parents to improve the meat performance of sheep by hybridization.Carrying out the cross improvement between Texel Sheep and Kazakh sheep,making full use of the genetic complementarity of the two breeds and improving the production performance of Kazakh sheep will help to promote the sustainable utilization and development of Kazakh sheep and promote the improvement of quality and efficiency of Kazakh sheep industry.Based on the previous work of the research group,this paper takes 1846 lambs obtained from four different hybrid combinations of Texel Sheep and Kazak sheep produced from 2020 to 2021 as the research object.By measuring the weight of lambs in different growth stages,using statistical methods to fit the growth curve,and comparing the growth potential and characteristics of different hybrid combinations in different stages,this paper selects the best hybrid combination,so as to formulate scientific and Provide basis for reasonable cross combination and cross fixation;At the same time,the factors affecting the growth and development of sheep were systematically analyzed to provide reference for reducing the impact of adverse factors on the growth of experimental population and effectively improving production efficiency.The main research contents and results are as follows:Research content1: Study on the early growth and development law of different hybrid combinationsIn order to compare the growth and development potential and characteristics of different hybrid combinations,four different hybrid combinations were completed in this experiment(Texel Sheep× F1、F2×F1、F2×Kazakh sheep、F1×F2)the weight of 1846 lambs at 17 different growth and development stages from birth to 180 days old was measured,and 19748 data were obtained.On this basis,Based on the previous genetic improvement of Kazak sheep,comparison of cumulative growth,absolute growth and relative growth of 1193 lambs at different growth stages from birth to 180 days of age in four different hybrid combinations;Logistic,Gompertz and Von Bertalanffy nonlinear fitting models were used to fit and analyze the growth curve of body weight growth data,establish the optimal regression equation and draw the growth curve.From birth to 180 days of age in lambs of different hybrid combinations,F2 × F1 hybrid lambs have fast growth speed,high growth intensity,significant weight gain,and can reach the inflection point weight faster when the inflection point weight is higher.Texel×F1,F2×Kazakh Hybrid lambs followed.In contrast,F1×F2 hybrid lambs have slower growth and development speed,lower growth intensity,and the body weight is significantly lower than other hybrid combinations of the same age.Although the male lambs has a high inflection point body weight,it takes too long to reach this body weight.Through the screening of different hybrid combinations,,it is considered that the hybrid combination with the best early growth and development performance is F2 ×F1。Research content 2: analysis of influencing factors of six-month-old lamb weightIn order to study the influencing factors of six-month weight of lambs,406 Te HA Hybrid F2 generation lambs were selected.The effects of non genetic factors such as gender,birth month,birth type,lamb birth weight,ewe age and population type on six-month weight of Te HA Hybrid F2 generation were analyzed by SPSS 25.0 software.The results showed that gender and birth weight had significant effects on the weight of six-month lambs(P < 0.01);The birth type had a significant effect on the sixmonth weight of lambs(P < 0.05),but the birth month,the age of ewes and the growing group had no significant effect on the six-month weight of lambs(P > 0.05)This study provides a basis for the genetic improvement of Kazak sheep to formulate scientific and reasonable cross combinations and cross fixation methods;At the same time,the factors affecting the growth and development of sheep were analyzed to provide reference for reducing the impact of adverse factors on the growth and development of the experimental population and effectively improving the production efficiency.