| The pig industry has always been the pillar industry of China's animal husbandry.China has become the world's largest producer and consumer of pork,with an annual inventory of pigs far exceeding that of other countries.However,the overall efficiency of China's pig industry is lower than that of developed countries.In particular,in recent years,with the shortage of energy shortages and environmental protection,the production efficiency of pigs has been improved,production costs have been reduced,and environmental pollution and resource waste have been reduced.An important issue that the pig industry needs to solve today.As a important economic trait,pig feed conversion efficiency accounts for more than 60% of the total production cost of the modern pig industry.It improves the feed conversion efficiency of pigs and can effectively increase production efficiency and reduce production costs.At present,the pig industry mostly uses the feed-to-weight ratio and the remaining feed intake to express the feed conversion efficiency.There are advantages and disadvantages for the two traits.The feed-to-weight ratio is a ratio trait,and there are certain limitations.Pigs with different genetic backgrounds may have the same material.The difference between the actual feed intake of pigs expressed in the remaining feed intake and the predicted feed intake for growth and maintenance was obtained by constructing feed intake and multiple linear regression,reflecting the genetic background of the animals.Actual metabolic differences,but there are many statistical models for calculating the remaining feed intake in the world,and there are no uniform norms.The results obtained are also different.In addition,studies have shown that the average daily gain of pigs with low residual feed intake is higher.Low,loss of appetite.After entering the 21 st century,with the vigorous development of electronic feeding equipment,a large number of calculations of feed conversion efficiency indicators have become possible,but due to the high price of electronic feeding equipment,operation and maintenance are time-consuming and laborious,and there are problems such as machine failure.A large amount of erroneous data is generated,resulting in data redundancy while increasing production costs.In view of the above problems,most of the foreign pig farms currently use the measurement strategy of measuring pigs 30-105 kg body weight stage,while some pig farms in China increase the production cost per unit time to reduce the production cost,using a half-way measurement strategy,that is,70-115 kg weight stage,However,whether this measurement strategy is scientific and reasonable has not been reported.Therefore,this experiment is based on the 568 Duroc feed intake data of Shanghai Xiangxin Livestock Co.,Ltd.to carry out the following work:Comparison of RFI calculation methods: Based on the data of 160,433 feed intakes of 568 Duroc,a total of 7 calculation formulas were compared in this study.The heritability of RFI was found to be 0.14?0.47,which is a medium heritability trait.The values of RFI obtained by 7 kinds of calculation methods were-0.04?0.11,and the correlation coefficients of growth traits and reproductive traits were close to 0,which were negatively related to eye muscle area and lean meat,and thickened with backfat.The corrected age of 115 kg body weight was positively related.Among them,the experiment found that when the backfat parameter was added to the formula,the heritability was 0.14?0.22,which was lower than the model without the backfat parameter(0.33?0.47).In addition,when multiple feeds were calculated by backthickness,average daily gain,medium-term metabolic weight and average daily feed intake,the genetic correlation between the calculated feed intake and the average daily gain was-0.05.Different from the genetic correlations(0.04?0.23)obtained by the other seven calculation methods.Feed conversion efficiency index comparison: The residual feed intake calculated by multiple regression using backfat,average daily gain,medium metabolism weight and average daily feed intake was-0.04±0.55,heritability was 0.20,and feed-to-weight ratio The genetic correlations of the average daily feed intake and the corrected 115 kg body weight were 0.90,0.83,and 0.30,respectively,and the genetic correlations with daily gain,backfat,eye muscle area,and lean meat were-0.05 and 0.15,respectively.-0.37,-0.48;the ratio of feed-to-weight to daily gain-toweight ratio was 2.62±0.51,heritability was 0.38,and the genetic correlation with the average daily feed intake and corrected 115 kg body weight was 0.56.And 0.34,the genetic correlation with the average daily gain,backfat,and eye muscle area were-0.47,0.18,-0.54,respectively.In summary,it can be found that the feed-to-weight ratio is higher than the residual feed intake and has a large negative genetic correlation with the average daily gain.Therefore,if the breeding goal is to accelerate the growth rate and genetic progress,the feed-to-weight ratio indicator can be selected.The remaining feed intake is highly genetically related to the average daily feed intake,so if the breeding goal is to improve feed conversion efficiency,you can choose the remaining feed intake index.Analysis of the determination stage of feed utilization efficiency: based on 54 feed intake data of Duroc with full feed intake data,the experiment divided it into the first half of the individual(30?70kg)according to the weight interval,and the latter half of the individual(70?115kg),the weight of the test is fixed at 115 kg,and the weight of open measurement is divided into 7 small groups for each stage of 10 kg.The results showed that individuals with 60?115kg body weight had the highest heritability,and the remaining feed intake at 40?115kg weight stage was the most relevant to the phenotype of the whole process.The fitted regression equation had the highest fitting degree.Therefore,although the heritability of the remaining feed intake is the highest in the 60-115 kg body weight stage,shortening the measurement stage will result in the loss of data and representative decline.The measurement strategy of the 40-115 kg weight stage can effectively improve production efficiency and reduce production costs.Provide ideas for early selection of pig feed utilization efficiency. |
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