Analysis Of Genetic Characteristics Of F₁ Hybrid Generation Of Dazu Black Goat And Inner Mongolia Cashmere Goat

Goat production is an important part of animal husbandry.it is an irreplaceable agricultural income industry in many places to fight poverty and to build moderately prosperous society.With the rapid development of sheep science and technology,the molecular breeding techniques,using marker-assisted selection（MAS）and genomic selection（GS）as the means,provide opportunities for genetic improvement on goat populations.However,due to less attention to goat phenotypic collection and analysis work,the goat breeding in our country made little improvement.In addition,the research on the genetic mechanism of body appearance and important economic characters of livestock and poultry is mainly based on single gene research,single character selection or candidate gene verification.neglecting the systematicness of biological traits,it often leads to poor results,one-sided research and lack of originality.Reference family（RF）can solve the above problems well.Therefore,two national goat breeds of Inner Mongolia cashmere goat（IMCG）and Dazu black goat（DBG）were used to build goat reference family.Detailedly,in 2015,20 IMCG ewes were introduced from Alashan area of Inner Mongolia,and they were mated with 5 DBG rams which originated in Chongqing.In this study,the F₁ and IMCG,DBG were measured and analyzed comprehensively,to accumulate data and explore research paths for subsequent molecular research.The results are as followings:1.Appearance.DBG is black color,white skin,IMCG is pink skin covered by white hair,F₁ Hybrid hair color is white and yellow,skin color is white and pink.Both DBG and IMCG have about 90%of the beard ratio,but F₁ only about 70%.Nearly all DBG individuals are short forehead hair type,100%IMCG is long,the ratio of long to short forehead hair of F₁ Hybrid is about 1:1.The incidence of para-nipples in F₁ was 36.4%,higher than 30%of DBG ewes and 12.5%of IMCG ewes.The F₁ Hybrid has richer body appearance than DBG and IMCG.2.Reproductive performance.The gestational period of IMCG was 150.00 d,which was significant higher than that of 149.12 d of DBG and 148.33 d of F₁（P<0.05）.There was no significant found between DBG and F₁（P>0.05）.With litter sizes,DBG,F₁ and IMCG averaged 2.36,1.83 and 1.16,respectively.The litter weight,DBG,F₁ and IMCG averaged 5.33 kg,4.29 kg and 3.07 kg,respectively.The mean birth weight of lambs produced by DBG,F₁ and IMCG were 2.29 kg,2.34 kg and 2.65 kg,respectively.The reproductive performance of the F₁ was between DBG and IMCG.3.Growth performance.The body weight and body size of F₁ were higher than DBG（P<0.01 or P<0.05）.The value of body size of F₁ was BCG>BL>BH,the growth rate of body size was BCG≈BL>BH.Almost all phenotypic correlation coefficients among the traits studied were high and positive,whereas the correlation coefficients of bode size with BW,orderd from BCG>BL>BH.The gap of these body sizes between F₁ and DBG,most obvious one is BCG,followed by BL and last one is BH.So the BCG was the main factor that influenced the BW of F₁ and DBG during preweaning period.The growth rate of F₁ is faster than DBG during preweaning period.4.Cashmere traits.The average lengths of cashmere of IMCG,DBG and F₁ were4.84 cm,4.02 cm and 2.84 cm,respectively,the average cashmere fineness was 15.76μm,15.92μm and 16.27μm.IMCG cashmere had the longest extension length and straightness rate.The differences in IMCG,DBG and F₁ were extremely significant（P<0.01）.The strength of cashmere of IMCG was significantly different from that of DBG and F₁（P<0.01）,indicating that DBG and F₁ were less curled and have good elasticity.The cashmere quality of F₁ was between DBG and IMCG.In conclusion,goat performance test is a systematic long-term basic work.The performance of IMCG,DBG and F₁ was determined in this study,and a large number of phenotypic data were obtained,which could provide support for related molecular research in the future.The F₁ Hybrid has richer body appearance than DBG and IMCG and growth rate is faster than DBG.The reproductive performance and cashmere quality of the F₁ was between DBG and IMCG.In the future,it is necessary to further standardize goat performance test,and refine the traits tested and to establish a phenotypic database for goat reference family application.