Nutrition and heredity coordinated regulation method for improving reproductive performance of downy sheep

Abstract

The invention provides a nutrition and heredity coordinated regulation method for improving reproductive performance of downy sheep, which comprises the following steps: collecting ear tissue or blood samples, detecting BMPR1B, GDF9, PRLR and ESR1 key reproductive gene loci, screening individuals carrying dominant genotypes to establish a high-yield core group, and increasing the target gene frequency to 65% or more. Performing differentiated nutrition regulation and control by combining genotypes: performing short-term optimal feeding before hybridization, and improving energy, protein, beta-carotene, vitamin E and an organic selenium additive; a BLUP and machine learning are utilized to optimize a regulation and control strategy, and precise and data-driven closed-loop management of reproductive performance is realized. According to the cooperative regulation method, the estrus rate, the conception rate, the lambing number and the lamb survival rate of the down sheep can be remarkably increased, the breeding interval is shortened, and the method is suitable for efficient breeding system construction of special economic sheep species of down producing goats and down producing sheep and has wide application and popularization prospects.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of animal nutrition and genetic breeding, in particular to a method for improving the reproductive performance of cashmere sheep through the synergistic regulation of nutrition and genetics. BACKGROUND

[0002] Cashmere sheep is an important special economic animal in China, and its cashmere has the characteristics of high fineness, good elasticity and strong warmth retention, and is an important source of high-end textile raw materials. Cashmere sheep generally have low reproductive rates, with most breeds mainly producing single offspring, and the double-offspring rate being less than 30%, which seriously restricts the breeding efficiency and the development of industrial scale.

[0003] Currently, the main method to improve the reproductive performance of cashmere sheep is to improve the nutritional level of the daily ration, especially to implement "short-term optimal feeding" Flushing before mating, to increase energy and protein intake, in order to promote follicular development and increase the number of ovulations. Previous studies have shown that moderate increases in metabolizable energy and the addition of antioxidants such as vitamin E, selenium, and beta-carotene can improve the estrus performance and conception rate of ewes.

[0004] Cashmere sheep is an important special economic animal resource in China, and its cashmere products play an important role in the high-end textile raw material market. However, cashmere sheep generally have low reproductive rates, such as low single-offspring rate, irregular estrus cycle, low conception rate, and low lamb survival rate, which seriously restricts the sustainable development of the industry. Traditionally, improving reproductive performance mainly relies on single nutritional regulation or genetic selection methods, but the effect is limited. In existing technologies, some studies have improved reproductive performance by supplementing energy, protein, vitamin E, selenium, zinc and other nutrients, but lack a systematic nutrition program. Genetic selection can improve fertility, but it takes a long time, is costly, and can lead to a decrease in cashmere production due to over-selection. Most existing farms still rely on experience management, lack individual reproductive records and data analysis systems, and cannot achieve precise prediction and dynamic adjustment, which restricts the continuous improvement of reproductive efficiency. In the process of pursuing high fertility, some selection or nutritional intervention measures have led to a decline in the body condition of ewes and a significant decrease in cashmere production, affecting the overall economic benefit, and there is a lack of technical solutions for the simultaneous improvement of reproduction and cashmere production. Therefore, a method for improving the reproductive performance of cashmere sheep through the synergistic regulation of nutrition and genetics is proposed. SUMMARY

[0005] The purpose of the present application is to solve the problems existing in the background art. In order to achieve the above-mentioned purpose of the application, the present application provides the following technical solution: a method for improving the reproductive performance of cashmere sheep through the synergistic regulation of nutrition and genetics, comprising the following steps: Step 1: Collect ear tissue or venous blood samples from individual fine wool sheep, extract genomic DNA, and detect key reproduction-related gene loci using PCR-RFLP or high-throughput SNP sequencing technology. Specifically, the following loci are detected: BMPR1B gene FecB site A746G GenBank: AF361027, GDF9 gene B4 mutation C397T GenBank: AY248500, PRLR gene c.1195A>G GenBank: NM_001009406, and ESR1 gene Hae III polymorphic site rs41256973. Each sample is detected twice to ensure accuracy, and the genotyping results are confirmed by BLAST alignment; Step 2: Select individuals with high reproductive potential based on genotype combinations, preferably ewes carrying both BMPR1B gene AG or GG type heterozygous or homozygous mutation and GDF9 gene CT or TT type, and individuals with PRLR gene AG / GG type and ESR1 gene BB / AB type are preferentially included. Eliminate individuals without dominant loci genes such as BMPR1B AA type and GDF9 CC type. Establish a high-yield core breeding population of not less than 200 individuals, and the target locus frequency in the population is increased to more than 65%; Step 3: During the 60 days before mating to 90 days after the end of lactation, implement differential nutrition regulation schemes based on genotypes: for individuals with dominant genotypes, implement short-term superior feeding 14 days before mating, increase the daily ration metabolizable energy from 8.8 MJ / kg to 9.8 MJ / kg, and increase the crude protein from 12.5% to 15.5%, and daily supplement β-carotene 200 mg / head, vitamin E 50 IU / kg feed, yeast selenium 0.3 mg / kg feed, and egg methionine zinc 60 mg / kg feed; after 90 days of pregnancy, the daily ration metabolizable energy is not less than 10.2 MJ / kg, the crude protein is 17.0%, and daily supplement choline 15 g, folic acid 10 mg, vitamin B 12 50 μg; during lactation, the daily ration metabolizable energy is ≥10.6 MJ / kg, the crude protein is 19.0%, and the conjugated linoleic acid CLA is added at 5 g / head / day to promote the improvement of colostrum quality; Step 4: Use double PGF2α injection method for synchronization of estrus treatment, first intramuscular injection of cloprostenol sodium 0.2 mg / head, interval 11 days, second injection of the same dose, artificial insemination is performed 48 hours after the second injection; confirm pregnancy by B-ultrasound 30 days after mating, establish individual electronic breeding file containing genotype, nutrition record, estrus time, lambing number, birth weight, weaning weight, and wool yield information, estimate breeding value using BLUP method, and dynamically optimize nutrition and management parameters for the next breeding cycle using machine learning model, to realize data-driven closed-loop regulation.

[0006] As the preferred technical scheme of the present application, the nutrition regulation scheme for 60 days before mating is as follows: for ewes carrying at least one FecB mutant site gene AG or GG, feeding daily ration with metabolic energy ME of 9.5-10.0 MJ / kg and crude protein CP of 14%-16%, and additionally supplementing vitamin E 50 IU / kg feed, organic selenium yeast selenium 0.3 mg / kg feed, egg methionine zinc 60 mg / kg feed and beta-carotene 200 mg / head / day, continuously feeding for not less than 45 days.

[0007] As the preferred technical scheme of the present application, short-term optimal feeding is implemented 14 days before mating, so that the total metabolic energy intake is increased by 20%-25% compared with the maintenance requirement, preferably the energy is increased by adding corn, puffed soybean or vegetable oil, and the daily ration starch content is controlled below 25% to avoid rumen acidosis.

[0008] As the preferred technical scheme of the present application, the nutrition regulation during pregnancy is divided into two stages: 1-90 days of early pregnancy: providing basic daily ration with ME 8.8-9.2 MJ / kg and CP 12%-14%; 91 days of late pregnancy to delivery: increasing to ME≥10.0 MJ / kg and CP 16%-18%, and daily supplementing choline 15 g, folic acid 10 mg, vitamin B 12 50 μg / head to support rapid fetal development and maternal liver metabolic function.

[0009] As the preferred technical scheme of the present application, high-nutrition-density daily ration is provided during the lactation period of 0-90 days after delivery, with metabolic energy≥10.5 MJ / kg, crude protein 18%-20%, calcium to phosphorus ratio controlled at 1.8:1, and additional addition of conjugated linoleic acid CLA 4-6 g / head per day to increase colostrum immunoglobulin content and lamb passive immunization capacity.

[0010] As the preferred technical scheme of the present application, the synchronization of estrus treatment adopts a double-time PGF2α injection scheme: first intramuscular injection of cloprostenol sodium 0.2 mg / head, second injection of the same dose after 11 days, artificial insemination or natural mating is performed 48 hours after the second injection, and the estrus synchronization rate is not less than 75%.

[0011] As the preferred technical scheme of the present application, an individual reproductive performance database is established to record the genotype, mating time, pregnancy diagnosis result, lambing number, lamb initial birth weight, weaning weight, survival rate and postpartum recovery time of each ewe, and the genetic breeding value EBV is updated once per reproductive cycle.

[0012] As a preferred technical solution of the present invention, a 3D database is constructed, and a prediction model is established using a neural network. The input parameters include genotype combination, nutrient intake, ambient temperature, parity and body condition score, and the output is the expected number of ovulations, the number of lambs born and the survival probability of lambs.

[0013] As a preferred technical solution of the present invention, the individual BCS score of the wool sheep is maintained at 3.0 to 3.55 before mating, not exceeding 4.0 in late pregnancy, and not lower than 2.8 during lactation.

[0014] As a preferred technical solution of the present invention, it also includes regular monitoring and evaluation, with the wool sheep being monitored every 2-3 months to detect blood glucose levels of 4-6 mmol / L, blood lipid levels of 1.5-3.0 mmol / L, and blood calcium levels of 2.2-2.7 mmol / L.

[0015] Compared with the prior art, the beneficial effects of this invention are as follows: the average number of lambs per litter in wool sheep increases from 1.45 to 1.98, an increase of 36.6%; the lambing rate increases from 137.8% to 189.8%, an increase of 52%; the conception rate increases by 15 percentage points, and the estrus synchronization rate reaches over 96%, significantly improving the reproductive efficiency of the flock; it effectively solves the industry problem of "low single-birth lambing and low reproductive rate" in wool sheep, providing a high-yield population foundation for large-scale breeding.

[0016] This invention's precise regulation mode implements differentiated nutritional supply for individuals carrying high-fertility genes such as BMPR1BFecB and GDF9; and significantly activates follicle development and ovulation potential through short-term eugenics and functional nutrient intervention before mating. With precise nutritional support, ewes recover quickly after giving birth, and the time to first estrus is shortened by an average of 13.2 days; the average number of breeding cycles per ewe is increased, and the annual lambing rate per ewe is significantly improved.

[0017] This invention features a standardized operating procedure, covering gene testing, feed formulation, breeding processing, and data recording, making it easy to promote in large-scale sheep farms. It can be integrated with smart farming systems to achieve individualized intelligent feeding and breeding early warning. This improves the productivity of individual ewes, reduces the number of inefficient individuals, and optimizes the population structure. It provides practical, high-yield farming technologies for pastoral and semi-agricultural / semi-pastoral areas, increasing farmers' income. It also promotes the transformation and upgrading of the cashmere sheep industry towards high quality and high efficiency. Attached image description: Figure 1 This invention provides a data flowchart of key reproduction-related gene detection site information. Figure 2 A data flowchart for screening individuals with high reproductive potential provided by this invention; Figure 3The synchronization of estrus and artificial insemination operation flowchart provided by the present application; Figure 4 The breeding file content and data optimization data block diagram provided by the present application. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below with reference to the drawings. Obviously, the described embodiments are a specific embodiment of the present application, and are not limited to all embodiments.

[0019] Therefore, the following detailed description of the embodiments of the present application is not intended to limit the scope of the claimed application, but only represents some embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative labor are within the scope of protection of the present application.

[0020] It should be noted that the embodiments in the present application and the features and technical solutions in the embodiments can be combined with each other without conflict, and it should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0021] Embodiment 1: A method for improving the reproductive performance of cashmere sheep by synergistic regulation of nutrition and heredity, comprising the following steps: Step 1: Collecting ear tissue or venous blood samples of cashmere sheep individuals, extracting genomic DNA, and detecting key reproductive-related gene sites by PCR-RFLP or high-throughput SNP sequencing technology, specifically including: BMPR1B gene FecB site A746G GenBank: AF361027, GDF9 gene B4 mutation C397T GenBank: AY248500, PRLR gene c.1195A>G GenBank: NM_001009406, and ESR1 gene Hae III polymorphism site rs41256973, each sample is detected twice to ensure accuracy, and the genotyping result is confirmed by BLAST alignment; Step 2: Screening high reproductive potential individuals according to genotype combination, preferably selecting ewes carrying BMPR1B gene AG or GG type heterozygous or homozygous mutation and GDF9 gene CT or TT type, and PRLR gene AG / GG type, ESR1 gene BB / AB type individuals are preferentially included, and individuals without dominant site genes such as BMPR1B AA type and GDF9 CC type are eliminated, and a high-yield core breeding population of not less than 200 is established, and the target site gene frequency in the population is increased to more than 65%; Step 3: During the period from 60 days before mating to 90 days after the end of lactation, different nutritional regulation schemes are implemented according to genotypes: for individuals with dominant genotypes, short-term superior feeding is implemented 14 days before mating, the daily ration metabolic energy is increased from 8.8 MJ / kg to 9.8 MJ / kg, the crude protein is increased from 12.5% to 15.5%, and 200 mg / head / day of beta-carotene, 50 IU / kg of vitamin E, 0.3 mg / kg of yeast selenium, and 60 mg / kg of zinc methionine are supplemented daily; after 90 days of pregnancy, the daily ration metabolic energy is not less than 10.2 MJ / kg, the crude protein is 17.0%, 15 g of choline, 10 mg of folic acid, 50 IU / kg of vitamin E, 0.3 mg / kg of yeast selenium, and 60 mg / kg of zinc methionine are supplemented daily; and the daily ration of the lactation period is ≥10.6 MJ / kg, the crude protein is 19.0%, and 5 g / head / day of conjugated linoleic acid (CLA) is added to promote the improvement of colostrum quality; 12 50 μg; the daily ration of the lactation period is ≥10.6 MJ / kg, the crude protein is 19.0%, and 5 g / head / day of conjugated linoleic acid (CLA) is added to promote the improvement of colostrum quality; Step 4: Synchronization of estrus is performed by double PGF2α injection method, the first injection is 0.2 mg / head of cloprostenol sodium, and the second injection is the same dose after 11 days, artificial insemination is performed 48 hours after the second injection; pregnancy is confirmed by B-ultrasound 30 days after mating, an individual electronic breeding file containing genotype, nutrition record, estrus time, lambing number, birth weight, weaning weight, and wool yield information is established, breeding values are estimated by BLUP method, and nutritional and management parameters of the next breeding cycle are dynamically optimized by combining machine learning models to realize data-driven closed-loop regulation.

[0022] The nutritional regulation scheme for 60 days before mating is that for ewes carrying at least one FecB mutant site gene AG or GG, a daily ration with metabolic energy (ME) of 9.5-10.0 MJ / kg and crude protein (CP) of 14%-16% is fed, and vitamin E 50 IU / kg of feed, organic selenium 0.3 mg / kg of feed, zinc methionine 60 mg / kg of feed, and beta-carotene 200 mg / head / day are additionally supplemented, and the continuous feeding time is not less than 45 days.

[0023] Short-term superior feeding is implemented 14 days before mating, the total metabolic energy intake is increased by 20%-25% compared to the maintenance requirement, and the energy is preferably increased by adding corn, puffed soybeans, or vegetable oil, the daily ration starch content is controlled to be below 25% to avoid rumen acidosis.

[0024] The pregnancy period nutritional regulation is divided into two stages: 1-90 days of early pregnancy: a basic daily ration with ME 8.8-9.2 MJ / kg and CP 12%-14% is provided; 91 days of late pregnancy to delivery: it is increased to ME ≥10.0 MJ / kg, CP 16%-18%, and 15 g of choline, 10 mg of folic acid, 50 IU / kg of vitamin E, 0.3 mg / kg of yeast selenium, and 60 mg / kg of zinc methionine are supplemented daily. 1250 μg / head, to support the rapid development of the fetus and maternal liver metabolic function.

[0025] During lactation, provide high-nutrient-density daily feed to the postpartum 0-90-day ewes, with metabolic energy ≥10.5 MJ / kg, crude protein 18%-20%, calcium-phosphorus ratio controlled at 1.8:1, and daily additional addition of conjugated linoleic acid CLA 4-6 g / head, to increase colostral immunoglobulin content and lamb passive immunization capacity.

[0026] The estrus synchronization treatment adopts a double-PGF2α injection scheme: first intramuscular injection of cloprostenol sodium 0.2 mg / head, second injection of the same dose after an interval of 11 days, artificial insemination or natural mating 48 hours after the second injection, and estrus synchronization rate not less than 75%.

[0027] Establish an individual reproductive performance database to record the genotype, mating time, pregnancy diagnosis result, lambing number, lamb birth weight, weaning weight, survival rate, and postpartum recovery time of each ewe, and update the genetic breeding value EBV once every reproductive cycle.

[0028] Construct a database and use a neural network to establish a prediction model, with input parameters including genotype combination, nutrient intake, environmental temperature, parity, and body condition score, and output being expected ovulation number, lambing number, and lamb survival probability.

[0029] The individual score BCS of the cashmere sheep is maintained at 3.0-3.55 points before mating, not more than 4.0 in the late pregnancy, and not less than 2.8 during lactation.

[0030] It also includes regular monitoring and evaluation, with monitoring of the cashmere sheep once every 2-3 months to detect blood glucose content of 4-6 mmol / L, blood lipid content of 1.5-3.0 mmol / L, and blood calcium content of 2.2-2.7 mmol / L.

[0031] The working principle of a method for synergistically regulating nutrition and genetics to improve the reproductive performance of cashmere sheep: the reproductive performance of cashmere sheep is controlled by multiple genes, among which the BMPR1B, GDF9, PRLR, and ESR1 genes are key regulatory factors that directly affect ovulation number, follicular development, corpus luteum function, and embryo survival rate. Individuals carrying the AG or GG type of the G site of the BMPR1B gene have enhanced follicular granulosa cell sensitivity to gonadotropin, which can significantly increase ovulation number and lambing number; The B4 mutation of the GDF9 gene can promote oocyte maturation and improve fertilization rate; the PRLR and ESR1 polymorphisms affect ewe estrus behavior, pregnancy maintenance, and lactation initiation.

[0032] This invention utilizes molecular marker technology to genotype individuals in a core population, screening for individuals with superior genotype combinations possessing high reproductive potential, thereby enhancing the genetic reproduction performance of the herd from the source. Genetic potential requires a suitable nutritional environment to be fully expressed. Based on the metabolic characteristics and physiological needs of individuals with different genotypes, this invention implements phased and precise nutritional regulation, beginning nutritional intervention 60 days before mating. Specifically, for ewes carrying the FecB high-fertility gene, a high-energy, medium-high protein diet (ME≥9.5 MJ / kg), CP 14%–16%, and supplementation is provided. Vitamin E and organic selenium: work synergistically to fight oxidation, protect the integrity of oocyte membranes, and improve fertilization rate; zinc methionine zinc: participates in DNA synthesis and cell division, and promotes follicle development; β-carotene: is converted into vitamin A, regulates the secretion of reproductive hormones, and enhances endometrial receptivity; short-term flushing: increases energy intake by 20% to 25% 14 days before mating, stimulates the pituitary gland to release FSH, and increases the number of ovulations, especially effective for individuals with multiple-laying genotypes.

[0033] During the later stages of pregnancy, fetal weight gain accounts for more than 70% of the total, increasing the metabolic burden on the mother. This invention addresses this by: Increase dietary energy (ME) to ≥10.0 MJ / kg and protein level (CP) to 16%–18% to meet the needs of rapid fetal growth; Supplementing with choline and folic acid: participates in methyl metabolism, prevents neural tube defects in the fetus, and improves placental function; maintains a calcium-to-phosphorus ratio of 1.8:1 to 2:1, preventing birth paralysis and dystocia caused by hypocalcemia; avoids excessive energy intake leading to fatty liver, and ensures healthy liver metabolism.

[0034] Severe negative energy balance in lactating ewes can negatively impact estrus recovery and reproductive capacity in subsequent litters. This invention provides a diet with high metabolizable energy (ME) ≥ 10.5 MJ / kg and high protein (CP) 18%–20%, supporting high-level lactation; supplemented with conjugated linoleic acid (CLA): regulating mammary gland lipid metabolism, increasing IgG content in colostrum, and enhancing passive immunity in lambs; ensuring free access to minerals, and preventing postpartum paralysis and metritis.

[0035] Based on the synergy of genetics and nutrition, the use of estrus synchronization and artificial insemination techniques enables centralized mating time, improved conception rate, and unified management of the lambing period: the double PGF2α injection protocol achieves an estrus synchronization rate of over 75%, facilitating centralized mating and lambing; combined with ultrasound pregnancy diagnosis, early identification of non-pregnant individuals allows for timely adjustment of management strategies; and the reproductive performance of each ewe is recorded to create individual files, providing data support for subsequent breeding and nutritional optimization.

[0036] The specific working process of the present application is as follows: the first stage: ewe screening and genetic evaluation T=180 days to 60 days: in the cashmere sheep breeding farm, 200-500 adult ewes with good health, good body condition score BCS 3.0-3.5 and age of 2-5 years are selected as candidate individuals to establish a core breeding group. Biological samples are collected and genotyped: ear tissue or blood samples of each ewe are collected, and genomic DNA is extracted; PCR-RFLP or high-throughput SNP typing technology is used to detect the following key reproduction-related gene sites: BMPR1B gene FecB site A746G; GDF9 gene B4 mutation C397T; PRLR gene c.1195A>G ; ESR1 gene Hae III polymorphism; the genotype is determined according to the detection result, and high reproductive potential individuals carrying FecB AG / GG and / or GDF9 CT / TT are screened.

[0037] Assembling a high reproductive breeding group: individuals with excellent genotypes, such as double-gene or multi-gene advantage combinations, are included in the key breeding group, and individuals without advantage sites are eliminated to form a ewe group with excellent genetic foundation.

[0038] The second stage: nutritional intervention and optimal feeding before mating T=60 days to mating day The selected ewes are given differential ration formula, specifically as follows: the composition of the basic ration is 40% corn, 25% alfalfa meal, 15% soybean meal, 10% wheat bran, 5% premix, and 2% oil; the nutritional index is 9.5-10.0 MJ / kg of metabolic energy ME, 14%-16% of crude protein CP; Additives: vitamin E: 50 IU / kg of feed, yeast selenium: 0.3 mg / kg of feed, methionine zinc: 60 mg / kg of feed, beta-carotene: 200 mg / head / day 14 days before the expected mating day, the energy intake is increased by 20%-25% by increasing corn or puffed soybeans; the estrus behavior is observed daily, and the initial estrus starting time is recorded.

[0039] Synchronization of estrus treatment: the first injection of cloprostenol sodium 0.2 mg / head, intramuscular injection; the same dose is injected after 11 days; artificial insemination or natural mating with high-quality breeding rams is performed 48 hours after the second injection. The third stage: dynamic nutrition regulation during pregnancy, from mating to delivery The first stage of pregnancy 1-90 days Maintain the basic nutrition level: ME 8.8-9.2 MJ / kg, CP 12%-14%; avoid excessive nutrition leading to early embryonic death; regular B-ultrasound examination confirms the pregnancy status at 30 and 60 days after mating.

[0040] 91 days to delivery; adjust the ration formula, increase energy and protein supply: ME≥10.0 MJ / kg, CP 16%-18%; add choline 15 g / head / day, folic acid 10 mg / head / day, vitamin B 12 50 μg / head / day; Control the ratio of calcium and phosphorus at 1.8:1-2:1 to prevent low blood calcium; monitor the body condition score every week to prevent excessive obesity BCS>4.0.

[0041] The fourth stage: lactation support and lamb breeding 0-90 days after delivery: provide a clean and warm delivery room environment with a temperature of ≥10℃ and a humidity of 60%-70%; ensure that the lamb completes the initial milk intake of ≥200 mL within 1 hour after birth; record the number of lambing, birth weight, gender, and abnormal conditions.

[0042] High nutritional supply during lactation: provide high-energy and high-protein rations: ME≥10.5 MJ / kg, CP 18%-20%; Daily supplement of conjugated linoleic acid CLA 5 g / head to improve the content of colostrum immunoglobulin; free access to mineral lick bricks containing Ca, P, Mg, Cu, Zn, and Se; ensure adequate drinking water with a water temperature of ≥15℃.

[0043] Lamb breeding: provide starter feed at 10 days of age to promote rumen development; perform the first weight measurement at 30 days of age, supplement with concentrate at 60 days of age, and wean at 90 days of age; record weaning weight, survival rate, and health status.

[0044] The fifth stage: data collection, effect evaluation, and system optimization: establish individual breeding records: establish electronic records for each ewe, record: estrus, breeding, and pregnancy diagnosis time; number of lambing, birth weight, weaning weight, and survival rate; postpartum recovery time, and next estrus initiation time; Statistical analysis of reproductive performance: after each breeding cycle, calculate: average number of lambs per ewe: lambing rate%=total number of lambs / bred ewes×100%; lamb survival rate after weaning; annual wool production of ewes g / year; update and optimize genetic breeding values EBV; calculate the breeding value of individual reproductive traits using the BLUP method; input genotype, nutritional parameters, and environmental factors into machine learning models such as random forests to predict the optimal nutrition plan under different combinations; The sixth stage: cyclic application and popularization Use the excellent offspring selected in this cycle as reserve breeding ewes; eliminate low-reproductive individuals to continuously improve the genetic level of the population; replicate the technical process in multiple farms to form standardized operating procedures SOP and achieve large-scale popularization.

[0045] Test example To verify the actual effect of the method for improving the reproductive performance of fine wool sheep through nutritional and genetic synergistic regulation.

[0046] I. Test materials and location Test animals: Xingji fine wool sheep from Huamupu Biological Technology Co., Ltd. of Tacheng Sheep Farm or Ordos fine wool sheep from Baoyinsurike Agricultural Development Co., Ltd. of Wushen Banner, 200 adult and productive ewes, aged 3-5 years, with a body condition score (BCS) of 3.0-3.55 points, and no reproductive system diseases.

[0047] Test period: September 1, 2023 to September 30, 2024, covering the pre-breeding, pregnancy, lactation, and weaning evaluation.

[0048] II. Test design 200 ewes were randomly divided into two groups, 100 in each group:

[0049] 1. Specific implementation steps of experimental group A 1. Genetic evaluation Ear tissue samples were collected, DNA was extracted, and BMPR1B FecB and GDF9 B4 genes were detected by PCR-RFLP method. The results showed that: 68 were FecB AG type, 22 were GG type, and a total of 90 carried mutant genes; 10 were AA type without mutation, marked but continued to participate in the test to observe the difference in nutritional response.

[0050] 2. Nutritional regulation scheme 60 days before breeding: feeding high-energy and high-protein diet, ME 9.8 MJ / kg, CP 15.5%, adding vitamin E 50 IU / kg, yeast selenium 0.3 mg / kg, methionine zinc 60 mg / kg, daily supplement of beta-carotene 200 mg; 14 days before breeding: short-term optimal feeding, energy intake increased by 22%, 3% puffed soybean was added in the diet; Pregnancy: Early stage 1-90 days: ME 9.0 MJ / kg, CP 13.5%; Later stage 91 days to delivery: ME 10.2 MJ / kg, CP 17.0%, daily supplement of choline 15 g, folic acid 10 mg; Lactation: ME 10.6 MJ / kg, CP 19.0%, daily addition of CLA 5 g / head.

[0051] 3. Reproduction management The same estrus was induced by twice PGF2α injection, 0.2 mg per sheep, with an interval of 11 days. Artificial insemination 48 hours after the second injection; B-ultrasound was used to confirm the pregnancy status after 30 days of pregnancy; A person was responsible for lambing during the delivery period, and lambing data was recorded.

[0052] 2. Treatment of control group B No genetic testing, all ewes were fed with basic diet ME 8.8 MJ / kg, CP 12.5%, only supplemented with conventional premix; Natural mating after estrus, no special feeding; No special adjustment of nutritional level during late pregnancy and lactation period; Normal lambing, data recording was carried out synchronously.

[0053] III. Determination index The following indicators were recorded in each group: Estrus rate%=number of estrus ewes / total number of ewes×100% Fertilization rate%=pregnant ewes / number of mating ewes×100% Average number of lambs born per ewe Lambing rate%=total number of lambs born / number of mating ewes×100% Lamb birth weight kg Weaning survival rate%=weaned live lambs / total number of lambs born×100% Time of first postpartum estrus in ewes Average annual wool production of adult ewes g-measured by weighing after shearing IV. Test results

[0054] Data is expressed as "mean ± standard deviation", t-test was performed using SPSS 26.0, P<0.05 is significant, P<0.01 is extremely significant.

[0055] V. Result analysis Reproductive performance improved significantly The average number of lambs born in the experimental group reached 1.98 per ewe, which was 36.6% higher than that of the control group, indicating that the synergistic effect of genetic screening and nutritional intervention effectively activated the expression of multiple lamb genes; The lambing rate was close to 190%, reaching the domestic advanced level.

[0056] Lambs' vitality was enhanced The birth weight increased by 8.7%, and the weaning survival rate increased to 94.2%, indicating that nutritional regulation during late pregnancy and lactation effectively supported fetal development and colostrum quality, reducing the risk of weak lambs and early death.

[0057] The ewe reproductive turnover is accelerated The time of the first estrus after delivery is shortened by 13.2 days, which is beneficial to realize the mode of one lamb per year or three lambs per two years and improve the annual reproductive efficiency.

[0058] The wool production performance is stable Although the reproductive load is increased, the wool production of the experimental group only decreases by 1.1%, and the difference is not significant, which indicates that the scheme does not cause negative effects on the wool production performance while improving the reproductive efficiency, and realizes the synergistic optimization of the production performance.

[0059] Six, conclusion The test results show that the genetic evaluation, precise nutrition and reproductive management synergistic regulation method can significantly improve the estrus rate, the conception rate, the number of lambs and the survival rate of lambs, shorten the reproductive interval, and does not affect the wool production performance. The technical scheme is scientific and feasible, has remarkable effect, and has strong replicability, and is suitable for the efficient breeding system construction of cashmere goats, cashmere sheep and special economic sheep breeds, and has wide application prospect.

[0060] The above examples are only used to illustrate the present application and not to limit the technical scheme described in the present application. Although the present application has been described in detail with reference to the above-mentioned various embodiments, the present application is not limited to the above-mentioned specific embodiments, and therefore any modification or substitution of the present application; all technical schemes which do not deviate from the spirit and scope of the present application and its improvements are all included in the scope of the claims of the present application.

Claims

1. A method for synergistic regulation of nutrition and genetics to improve the reproductive performance of cashmere sheep, characterized in that, Includes the following steps: Step 1: Collect ear tissue or venous blood samples from individual wool sheep, extract genomic DNA, and use PCR-RFLP or high-throughput SNP sequencing technology to detect key reproduction-related gene loci, specifically including: BMPR1B gene FecB locus A746G (GenBank: AF361027), GDF9 gene B4 mutation C397G (GenBank: AY248500), PRLR gene c.1195A>G (GenBank: NM_001009406), and ESR1 gene HaeⅢ polymorphism locus rs41256973. Each sample was tested twice to ensure accuracy, and the genotyping results were confirmed by BLAST comparison. Step 2: Select individuals with high reproductive potential based on genotype combinations. Prioritize ewes that simultaneously carry heterozygous or homozygous mutations of the BMPR1B gene AG or GG type and the GDF9 gene CT or TT type. Individuals with PRLR gene AG / GG type and ESR1 gene BB / AB type will be given priority. Eliminate individuals without dominant genes, such as BMPR1B AA type and GDF9 CC type. Establish a high-yielding core breeding group of no less than 200 sheep, with the frequency of the target gene in the group increased to more than 65%. Step 3: From 60 days before mating to 90 days after delivery at the end of lactation, implement a differentiated nutritional regulation program based on genotype: For individuals with the dominant genotype, implement short-term intensive feeding 14 days before mating, increasing the dietary metabolizable energy from 8.8 MJ / kg to 9.8 MJ / kg, and crude protein from 12.5% ​​to 15.5%, and supplementing daily with β-carotene 200 mg / head, vitamin E 50 IU / kg feed, yeast selenium 0.3 mg / kg feed, and methionine zinc 60 mg / kg feed; after 90 days of gestation, the dietary metabolizable energy should not be less than 10.2 MJ / kg, and the crude protein should reach 17.0%, supplementing daily with choline 15 g, folic acid 10 mg, and vitamin B1. 12 50μg; the daily metabolizable energy of the lactating diet is ≥10.6 MJ / kg, the crude protein is 19.0%, and conjugated linoleic acid (CLA) is added at 5 g / head·day; Step 4: Estrus synchronization was achieved using a double PGF2α injection method. The first injection was 0.2 mg / head of cloprostenol sodium intramuscularly, followed by a second injection of the same dose 11 days later. Artificial insemination was performed 48 hours after the second injection. Pregnancy was confirmed by ultrasound 30 days after mating. An individual electronic breeding record was established, including information on genotype, nutritional records, estrus time, number of lambs, birth weight, weaning weight, and wool production. Breeding values ​​were estimated using the BLUP method, and the nutritional and management parameters for the next breeding cycle were dynamically optimized using a machine learning model, enabling data-driven closed-loop regulation.

2. The method for synergistic regulation of nutrition and genetics to improve the reproductive performance of cashmere sheep according to claim 1, characterized in that, The nutritional regulation program for the 60 days prior to mating is as follows: For ewes carrying at least one FecB mutant gene AG or GG, feed a diet with a metabolizable energy (ME) of 9.5–10.0 MJ / kg and a crude protein (CP) of 14%–16%, and supplement with vitamin E 50 IU / kg feed, organic selenium yeast selenium 0.3 mg / kg feed, methionine zinc 60 mg / kg feed and β-carotene 200 mg / head / day, for a continuous period of no less than 45 days.

3. A method for synergistic regulation of nutrition and genetics to improve the reproductive performance of cashmere sheep according to claim 1 or 2, characterized in that, Implement short-term high-quality feeding 14 days before mating to increase total metabolizable energy intake by 20% to 25% above maintenance requirements. Energy can be increased by adding corn, puffed soybeans or vegetable oil, while keeping the starch content of the diet below 25%.

4. The method for synergistic regulation of nutrition and genetics to improve the reproductive performance of cashmere sheep according to claim 1, characterized in that, Nutritional regulation during pregnancy is divided into two stages: During the first 1-90 days of pregnancy: provide a basal diet with ME 8.8-9.2 MJ / kg and CP 12%-14%; From the last 91 days of pregnancy to delivery: increase ME ≥ 10.0 MJ / kg, CP 16%–18%, and supplement with choline 15 g, folic acid 10 mg, and vitamin B daily. 12 50μg / head.

5. The method for synergistic regulation of nutrition and genetics to improve the reproductive performance of cashmere sheep according to claim 1, characterized in that, During the lactation period, from 0 to 90 days postpartum, provide a high nutrient density diet with metabolizable energy ≥10.5 MJ / kg, crude protein 18%–20%, calcium-to-phosphorus ratio controlled at 1.8:1, and add 4–6 g / head of conjugated linoleic acid (CLA) daily.

6. The method for synergistic regulation of nutrition and genetics to improve the reproductive performance of cashmere sheep according to claim 1, characterized in that, The estrus synchronization treatment involved two injections of PGF2α, with 0.2 mg / head of cloprostenol sodium injected intramuscularly. The same dose was injected a second time 11 days later. Artificial insemination or natural mating was performed 48 hours after the second injection, and the estrus synchronization rate was not less than 75%.

7. The method for synergistic regulation of nutrition and genetics to improve the reproductive performance of cashmere sheep according to claim 1, characterized in that, Establish an individual reproductive performance database to record each ewe's genotype, mating time, pregnancy diagnosis results, number of lambs, lamb birth weight, weaning weight, survival rate, and postpartum recovery time, and update the genetic breeding value (EBV) once per breeding cycle.

8. The method for synergistic regulation of nutrition and genetics to improve the reproductive performance of cashmere sheep according to claim 1, characterized in that, A 3D database was constructed, and a prediction model was built using a neural network. The input parameters included genotype combination, nutrient intake, ambient temperature, parity, and body condition score. The outputs were the expected number of ovulations, the number of lambs born, and the lamb survival probability.

9. The method for synergistic regulation of nutrition and genetics to improve the reproductive performance of cashmere sheep according to claim 1, characterized in that, The individual BCS score of the wool sheep was maintained at 3.0 to 3.55 before mating, not exceeding 4.0 in late pregnancy, and not lower than 2.8 during lactation.

10. The method for synergistic regulation of nutrition and genetics to improve the reproductive performance of cashmere sheep according to claim 9, characterized in that, It also includes regular monitoring and assessment, with cashmere sheep being monitored every 2-3 months to check blood glucose levels at 4-6 mmol / L, blood lipid levels at 1.5-3.0 mmol / L, and blood calcium levels at 2.2-2.7 mmol / L.

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