Efficient white pig breeding method

Abstract

The invention discloses an efficient white pig breeding method, and relates to the field of animal husbandry. The method comprises the following steps: screening individuals carrying excellent alleles on target economic character related gene loci through a gene detection technology to establish a core group; performing phenotype determination on growth, reproduction and meat traits of the individuals of the core group; based on genotype and phenotype data, an optimal linear unbiased prediction model is adopted to calculate an individual comprehensive breeding value, and an optimal matching scheme is formulated; standardized environment control is carried out in all stages from mating to fattening, and it is ensured that the environment conditions of pigs in the same period are consistent; and performing marking, determination and genetic evaluation on the offspring, and selecting and remaining excellent individuals for generation replacement. According to the method, molecular breeding, statistical inheritance and precise management are combined, the defects that a traditional breeding method is low in efficiency, long in period and poor in accuracy are effectively overcome, the genetic progress can be remarkably accelerated, multiple economic characters can be synchronously improved, and the consistency of group production performance is improved.

Description

Technical Field

[0001] This invention relates to the field of animal husbandry, specifically to a method for breeding high-efficiency white pigs. Background Technology

[0002] Pork is a major source of animal protein in the diet of residents, and its stable supply and quality improvement are crucial. Currently, the commercial pig market is mainly dominated by imported lean-type pig breeds such as Duroc, Landrace, and Large White, and their three-way crossbreeds. These breeds have advantages such as fast growth rate, high feed conversion ratio, and high lean meat percentage, making a significant contribution to ensuring pork supply. At the same time, to meet the market's differentiated demand for flavorful meats, the model of producing high-quality pork using local pig breeds as the maternal line has also gained a foothold. However, whether it is efficient production for the mass market or quality production for the high-end market, the core depends on continuous and efficient breeding work.

[0003] Traditional methods of breeding white pigs rely heavily on conventional breeding techniques, with their core being selection and mating based on phenotypic records of individuals and their relatives. While this method was effective for a period, it has significant limitations. First, its breeding efficiency is low because phenotypic traits are the result of the combined effects of genetic and environmental factors. Selection based solely on phenotypic traits makes it difficult to accurately distinguish between genetic and environmental advantages, leading to slow genetic progress and a lengthy breeding cycle. Second, for certain important economic traits, phenotypic determination is difficult and costly, or can only be obtained after individual slaughter, further limiting the accuracy and efficiency of breeding. Furthermore, traditional methods often lack systematic planning in mating strategies, resulting in insufficient control of inbreeding risks and a decline in population genetic diversity and inbreeding depression. Finally, fluctuations in the feeding and management environment can introduce significant environmental errors, masking true genetic differences and greatly reducing the accuracy of genetic assessments.

[0004] Therefore, existing white pig breeding methods generally suffer from multiple technical problems, including low breeding efficiency, long cycles, high costs, and difficulty in synergistically improving growth efficiency and pork quality. This makes it difficult for breeding results to quickly respond to changes in market demand and meet the urgent requirements of modern animal husbandry for "efficient, high-quality, and stable" production. Summary of the Invention

[0005] The purpose of this invention is to provide a high-efficiency breeding method for white pigs, in order to solve the problems of low breeding efficiency, long cycle, high cost, and difficulty in synergistically improving growth efficiency and pork quality in the existing technology.

[0006] To solve the above problems, the present invention employs the following technical means: A method for breeding high-efficiency white pigs includes the following steps: S1. Gene screening: Gene typing of the basic herd of white pigs is carried out using gene detection technology. Individuals carrying superior alleles at gene loci related to the target economic traits are selected to form the core breeding herd. S2. Phenotypic evaluation: Phenotypic determination of growth performance, reproductive performance and flesh quality traits of individuals in the core breeding population; S3. Genetic evaluation and mating: Based on the genotype information obtained in step S1 and the phenotypic information obtained in step S2, the comprehensive breeding value of individuals is calculated using the best linear unbiased prediction model, and an optimized mating scheme to avoid inbreeding is formulated based on the comprehensive breeding value. S4. Environmental control and feeding management: Standardized environmental control and feeding management shall be implemented for the core breeding population and its offspring at each stage of mating, pregnancy, farrowing, lactation, growth and fattening, wherein the environmental conditions of pigs at the same growth stage shall be kept consistent. S5. Offspring selection and breeding: Individual markers are used to mark the offspring population produced by the selection and mating, and their target phenotypic data are tracked and measured. Genetic evaluation is carried out in combination with their genotype data. Individuals with excellent evaluation are selected for the new generation of core breeding population. Steps S1 to S5 are repeated for continuous selection and breeding.

[0007] Preferably, in step S1, the target economic trait-related gene loci include specific loci in the PRKAG3, RYR1, and MC4R genes; the screening of individuals carrying superior alleles refers to screening individuals who are homozygous or heterozygous for superior alleles at the gene loci, and for the RYR1 gene, screening individuals negative for stress-sensitive genes.

[0008] Furthermore, in step S2, the phenotypic determination includes: Growth performance indicators: The age at which the animal reaches 100kg body weight is measured, with an excellent standard of ≤160 days; the backfat thickness at 100kg body weight is measured, with an excellent standard of ≤15mm; the feed conversion ratio is calculated, with an excellent standard of ≤2.6:1. Reproductive performance indicators: record the number of offspring, with the excellent standard being a total number of offspring ≥ 12 per litter; Meat quality indicators: Intramuscular fat content is measured, with an excellent standard of 2.5%-3.5%.

[0009] Furthermore, in step S3, the calculation of the comprehensive breeding value of an individual is to combine the breeding values ​​of each target trait into a comprehensive selection index according to their economic weights. The economic weights are: growth rate weight 30%, lean meat percentage weight 25%, reproductive performance weight 25%, and meat quality trait weight 20%.

[0010] Furthermore, in step S3, the formulation of the optimized configuration scheme specifically includes: Establish a mating expectation file to record the genotypes, comprehensive breeding values, and reasons for mating of both breeding partners; When selecting a mating pair, the kinship coefficient should be kept below 5%, and complementary or homogeneous mating strategies should be adopted.

[0011] Furthermore, in step S4, the standardized environmental control includes: Temperature control: During the growing and finishing pig stage, the temperature inside the pig house should be controlled at 18-22℃, with a fluctuation range not exceeding ±2℃; Humidity control: The relative humidity inside the building should be maintained at 60%-70%; Ventilation control: Ensure that the ammonia concentration in the building is below 15 ppm and the carbon dioxide concentration is below 1500 ppm.

[0012] Furthermore, in step S4, the requirement that pigs at the same growth stage maintain consistent environmental conditions means that pigs from the same batch are raised under the same temperature, humidity, feed formula, and feeding management procedures.

[0013] Furthermore, in step S5, the selection of individuals with excellent evaluations to be retained in the new generation core breeding population refers to selecting individuals ranked in the top 15% of the comprehensive selection index.

[0014] The present invention has the following beneficial effects during use: Traditional breeding relies on phenotypic selection, which is highly susceptible to environmental interference and slows genetic progress. This invention utilizes gene detection technology to accurately screen individuals carrying superior genotypes at an early stage (e.g., at weaning), enabling early selection of traits that are difficult to measure directly or only manifest later (such as meat quality and disease resistance), overcoming the blindness of traditional methods that rely solely on appearance. Simultaneously, combining genetic evaluation with an optimal linear unbiased predictive model effectively isolates environmental effects and more accurately estimates an individual's genetic breeding value, resulting in selection accuracy far exceeding traditional methods. This triple validation of "genotype + phenotype + statistical model" ensures that only individuals with the best genetic quality are selected for the core population, thereby significantly accelerating the genetic progress of the core population and reducing the genetic improvement effect that traditional methods require 5-6 generations to achieve to only 3-4 generations.

[0015] Traditional breeding methods often struggle to balance the negative genetic correlations between different traits (such as growth rate and meat quality). This invention constructs a comprehensive selection index, assigning reasonable economic weights to key economic traits such as growth rate, lean meat percentage, reproductive performance, and meat quality, enabling simultaneous selection of multiple traits. This method avoids the negative impacts of over-selection for a single trait, guiding breeding towards a more balanced approach that aligns with market demands. The resulting new white pig breed possesses excellent characteristics such as rapid growth, high meat yield, strong reproductive capacity, and superior meat flavor, significantly enhancing its overall economic value.

[0016] This invention explicitly requires controlling the kinship coefficient between the two breeding pairs to be below 5% in its mating strategy and establishing detailed pedigrees and mating records, thereby systematically avoiding the inbreeding depression problem caused by indiscriminate mating. This helps maintain sufficient genetic diversity in the core population, providing a solid foundation for subsequent continuous breeding and ensuring the long-term sustainability of breeding work.

[0017] This invention emphasizes the uniformity of environmental conditions for pigs at the same growth stage. By strictly controlling environmental factors such as temperature, humidity, ventilation, and density at each growth stage, environmental variance is minimized. This ensures high comparability of phenotypic data measured across different batches and individuals, significantly improving the accuracy of genetic assessment using the optimal linear unbiased prediction model. Simultaneously, stable and suitable environmental conditions maximize the release of the genetic potential of superior genotypes, ensuring stable growth rate, health level, and meat quality in the pig herd, and reducing production fluctuations. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments.

[0019] Therefore, the following detailed description of embodiments of the present invention is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0020] It should be noted that, unless otherwise specified, the embodiments and features described in this invention can be combined with each other.

[0021] Example 1 Establishment of basic group and core group From the Large White crossbred sow population, 600 healthy sows and 30 boars without genetic diseases were randomly selected as the initial breeding stock. Genetic testing was performed on all individuals using the GGP Porcine HD chip. Individuals with superior alleles (homozygous or heterozygous) at the MC4R (growth efficiency) and PRKAG3 (meat quality) loci, and negative for the RYR1 stress-sensitive genotype (stress resistance), were selected. Finally, 400 sows and 15 boars were selected to form the initial core breeding herd.

[0022] Precise phenotypic determination Rigorous phenotypic determination was performed on individuals in the core group: Growth performance: Record the age at which the animal reaches 100 kg body weight and measure the live backfat thickness at 100 kg body weight (B-ultrasound).

[0023] Reproductive performance: Record the total number of piglets born to the sow.

[0024] Meat quality characteristics: One offspring was randomly selected from each litter for slaughter testing, and the intramuscular fat content was measured.

[0025] Genetic evaluation and optimized mating Genotypic, phenotypic, and pedigree data for all individuals were collected, and the BLUP model was used to calculate the overall breeding value (EBV) for each individual. The economic weights of the overall selection index were set as follows: growth rate (-30%), backfat thickness (-25%), litter size (25%), and intramuscular fat (20%). Based on EBV ranking, the top 50% of sows and the top 80% of boars with the highest EBV were selected for breeding. Before breeding, kinship was analyzed using software to ensure that the kinship coefficient of all breeding combinations was below 5%, and a complementary selection strategy was adopted (e.g., pairing the boar with the highest growth rate EBV with the sow with the highest litter size EBV). An electronic record was created for each breeding session.

[0026] Standardized environmental control All core herds and their offspring are housed in modern, environmentally controlled pigsties. The key is strict adherence to "synchronized environmental consistency": piglets and growing pigs of the same batch and age are housed in separate pens with identical environmental conditions. The temperature inside the pens is controlled at (20±1)℃ during the growing-finishing period via a fan and water curtain system, humidity is controlled at 65%±5%, and ammonia concentration is <10ppm. The stocking density is 0.9 square meters per head for finishing pigs. Feed, immunization programs, and operator procedures are completely standardized.

[0027] Offspring selection and generational succession The offspring are electronically ear-tagged, and performance is measured through a process of precise phenotypic determination and standardized environmental control. At the end of each generation, the top 15% of individuals are selected for the next generation core group based on the latest comprehensive selection index. Completing a full breeding generation (from mating to the completion of offspring testing) takes approximately 12 months.

[0028] Comparative Example 1 The main difference between this method and Example 1 is that no genetic testing is performed. Instead, 400 sows and 15 boars with "superior conformation" are subjectively selected from the same base population based on appearance and preliminary growth records to form the core group.

[0029] The selection process relies solely on phenotypic records and does not use the BLUP model. Instead, it simply selects the individuals with the shortest age (100kg) and thinnest backfat for mating.

[0030] Environmental management was carried out using conventional methods, but the environmental conditions varied somewhat between different batches of pigs.

[0031] The generation interval is similar to that of Example 1.

[0032] Comparative Example 2 The main difference between the method and Example 1 is that the gene screening, BLUP model and matching strategy of Example 1 are used in its entirety.

[0033] However, environmental control is not implemented to ensure uniformity of the environment during the same period. Pigs are allocated according to the convenience of the pen space, and there are obvious temperature differences (16-25℃), humidity differences and ventilation differences between different pens.

[0034] The aim is to verify that even with advanced breeding techniques, excessive environmental noise can severely affect the accuracy of genetic assessment.

[0035] Comparative Example 3 The main difference between this method and Example 1 is that gene screening is not performed, and the selection method is the same as in Comparative Example 1.

[0036] However, the same standardized environmental controls as in Example 1 are implemented.

[0037] The selection is based on phenotype and does not use the BLUP model.

[0038] The aim is to verify the effect of simply improving environmental management without combining it with modern breeding techniques on genetic progress.

[0039] The above examples and comparative examples were implemented over three complete generations (36 months). The genetic progress of the main traits in each generation of the core population (annual genetic gain of the overall selection index) and the consistency of the offspring population's production performance (standard deviation of age at 100 kg body weight) were used as the core evaluation indicators. The experimental results are recorded in the table below: As shown in the table above, in terms of the rate of genetic progress, the annual genetic gain of the comprehensive selection index of Example 1 is significantly higher than that of all comparative examples. After three generations, the cumulative genetic progress of Example 1 is more than five times that of Comparative Example 1, fully demonstrating that the "genotype / phenotype / BLUP / uniform environment" system scheme of this invention can greatly accelerate the breeding process. From the perspective of the contribution of technical aspects, although the genetic progress of Comparative Example 2 (with gene technology but inconsistent environment) is better than that of Comparative Examples 1 and 3, it is much lower than that of Example 1, proving that the noise introduced by the inconsistency of the environment seriously interferes with the accuracy of the BLUP model and weakens the advantages of gene technology. Uniform environment control is an indispensable key link for achieving efficient breeding. The genetic progress of Comparative Example 3 (only optimized environment) is slightly higher than that of Comparative Example 1, and the offspring uniformity (standard deviation decreases) is improved, indicating that improving the environment itself is beneficial, but without precise genetic means (gene screening, BLUP), its genetic improvement efficiency is still low. In terms of population uniformity, the standard deviation of Example 1 and the offspring at 100kg age continues to decrease significantly, indicating that the pig herd bred by this invention has highly consistent production performance, which is conducive to standardized and industrialized production. There was no improvement in the neatness of Comparative Example 1, and the improvement in Comparative Examples 2 and 3 was limited.

[0040] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for breeding high-efficiency white pigs, characterized in that, Includes the following steps: S1. Gene screening: Gene typing of the basic herd of white pigs is carried out using gene detection technology. Individuals carrying superior alleles at gene loci related to the target economic traits are selected to form the core breeding herd. S2. Phenotypic evaluation: Phenotypic determination of growth performance, reproductive performance and flesh quality traits of individuals in the core breeding population; S3. Genetic evaluation and mating: Based on the genotype information obtained in step S1 and the phenotypic information obtained in step S2, the comprehensive breeding value of individuals is calculated using the best linear unbiased prediction model, and an optimized mating scheme to avoid inbreeding is formulated based on the comprehensive breeding value. S4. Environmental control and feeding management: Standardized environmental control and feeding management shall be implemented for the core breeding population and its offspring at each stage of mating, pregnancy, farrowing, lactation, growth and fattening, wherein the environmental conditions of pigs at the same growth stage shall be kept consistent. S5. Offspring selection and breeding: Individual markers are used to mark the offspring population produced by the selection and mating, and their target phenotypic data are tracked and measured. Genetic evaluation is carried out in combination with their genotype data. Individuals with excellent evaluation are selected for the new generation of core breeding population. Steps S1 to S5 are repeated for continuous selection and breeding.

2. The method for breeding high-efficiency white pigs according to claim 1, characterized in that, In step S1, the target economic trait-related gene loci include specific loci in the PRKAG3, RYR1, and MC4R genes; the screening of individuals carrying superior alleles refers to screening individuals who are homozygous or heterozygous for superior alleles at the gene loci, and for the RYR1 gene, screening individuals who are negative for stress-sensitive genes.

3. The breeding method for a high-efficiency white pig according to claim 1, characterized in that, In step S2, the phenotypic determination includes: Growth performance indicators: The age at which the animal reaches 100kg body weight is measured, with an excellent standard of ≤160 days; the backfat thickness at 100kg body weight is measured, with an excellent standard of ≤15mm; the feed conversion ratio is calculated, with an excellent standard of ≤2.6:

1. Reproductive performance indicators: record the number of offspring, with the excellent standard being a total number of offspring ≥ 12 per litter; Meat quality indicators: Intramuscular fat content is measured, with an excellent standard of 2.5%-3.5%.

4. The breeding method for a high-efficiency white pig according to claim 1, characterized in that, In step S3, the calculation of the comprehensive breeding value of an individual is to combine the breeding values ​​of each target trait into a comprehensive selection index according to their economic weights. The economic weights are: growth rate weight 30%, lean meat percentage weight 25%, reproductive performance weight 25%, and meat quality trait weight 20%.

5. The method for breeding a high-efficiency white pig according to claim 1 or 4, characterized in that, In step S3, the formulation of the optimized configuration scheme specifically includes: Establish a mating expectation file to record the genotypes, comprehensive breeding values, and reasons for mating of both breeding partners; When selecting a mating pair, the kinship coefficient should be kept below 5%, and complementary or homogeneous mating strategies should be adopted.

6. The breeding method for a high-efficiency white pig according to claim 1, characterized in that, In step S4, the standardized environmental control includes: Temperature control: During the growing and finishing pig stage, the temperature inside the pig house should be controlled at 18-22℃, with a fluctuation range not exceeding ±2℃; Humidity control: The relative humidity inside the building should be maintained at 60%-70%; Ventilation control: Ensure that the ammonia concentration in the building is below 15 ppm and the carbon dioxide concentration is below 1500 ppm.

7. The method for breeding a high-efficiency white pig according to claim 1, characterized in that, In step S4, the environmental conditions of pigs at the same growth stage are kept consistent, which means that pigs of the same batch are raised under the same temperature, humidity, feed formula and feeding management procedures.

8. The method for breeding high-efficiency white pigs according to claim 1, characterized in that, In step S5, the selection of individuals with excellent evaluations to be retained in the new generation core breeding population refers to selecting individuals ranked in the top 15% of the comprehensive selection index.

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