| Yanan pig,a valuable animal genetic resource,has the characteristics of good reproductive performance,strong resistance and good meat quality.In recent years,due to the impact of "lean meat type" pigs,the development of Yanan pig has been slow.With the increasing living standards of the nation,lean meat type pigs are far from meeting the demand for high quality pork.Therefore,the market for quality pork has gradually expanded,and the opportunities for local pigs are coming.However,at present,there is little research on the genetic characteristics of Yanan pig,and its hybridization utilization is also at the exploratory stage.Based on the protection and development of Yanan pig genetic resources and according to the theory of population genetics and the actual situation of the seed farm,we optimized the number of seed conservation groups,formulated the living conservation program of Yanan pig,and cryopreserved semen of Yanan pig boar using the existing core group of the original seed farm of the Yanan pig.We collected and collated the actual production data of the reproductive traits of Yanan pig for2014-2018,and analyzed the main reproductive traits of Yanan pig.The annual,seasonal and parity effects were analyzed.ASRemel software was used to estimate the heritability,repeatability and genetic correlation of three major population genetic parameters of Yanan pig,and lay the foundation for their genetic evaluation.Based on market demand and the need for cross breeding of local pigs,the hybrid experiment was conducted in Yanan pig.Growth traits,carcass traits,meat quality traits,amino acid composition of muscle and fatty acid group were compared among the three hybrid pigs of Yanan pig,DY and DBY.The following conclusions are drawn from this study:(1)When the ratio of boar to sows' breeding cost was m1/m2=15 and inbreeding increment F was lower than 0.002,the most economical population number was calculated to be 174,and the most economical males and females were 54 boars and 120 sows,respectively;(2)The semen cryopreservation of 5 boars in Yanan pig showed that there was agreat difference in the effect of frozen semen.The range of vitality after freezing was20%-61%.Thawing pigs were defrosting by 5 different procedures.It was found that the thawing efficiency of Yanan pig was best at “37 ?,10s” and “56 ?,6s”;(3)The annual analysis of main reproductive traits of Yanan pig showed that the total litter size and litter size of Yanan pig increased significantly in 2014-2018.The total litter size in 2018 increased by 0.51 compared with that in 2014,and the number of live births increased by 0.31 compared with that in 2014.The parity effect analysis showed that the total litter size from first to eighth showed a steady upward trend and a downward trend,and the reproductive performance was third.The total litter size was 11.67 and the live litter size was 10.91,respectively.The low peak yield was first and eighth parity,the total litter size was 10.22 and 10.74 respectively.The seasonal effect analysis showed that the total litter size and litter size of Yanan pig in summer were significantly lower than those in other seasons(P<0.05),the total litter size was only 10.51,and the number of live births was only 9.77;(4)The main reproductive traits of Yanan pig belonged to low heritability.Heritability of total litter size,litter size,birth weight,birth weight and weaning were 0.24,0.15,0.03,0.03 and 0.03 respectively.The main reproductive traits of Yanan pig belonged to low repetitive traits.The repeatability of total litter size,litter size,birth weight,birth weight and weaning were 0.26,0.2,0.14,0.09 and 0.03 respectively;(5)To evaluate the hybridization effect of Yanan pigs,the crossbreeding of Yanan pigs with Duroc and Berkshire breeds improves growth and carcass parameters to some extent.Crossbreeds,especially DBY pigs,exhibit acceptable meat quality characteristics similar to YN pigs.And a higher PUFA: SFA ratio was observed in DBY and YN pigs.These results indicated that the DBY crossbreed exhibits an acceptable total production performance and could be extensively used in commercial pig production to provide high-quality niche products. |
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