Breeding pigs are the basis for the proliferation of pigs and are the core of the entire pig production. Since the use of breeding pigs has a finite number of years, boars do not normally exceed 2 years in natural mating, sows do not exceed 8 litters, harvesting boars use 3 to 4 years, sows do not exceed 8 litters, and the breeding performance of individual pigs big difference. Therefore, only by implementing a scientific and reasonable breeding and renewal system for breeding pigs can we stabilize or increase the production level of breeding pigs and achieve the purpose of improving the economic efficiency of the farm. So, how to eliminate and renew breeders? Calculating the relevant data for the culling and renewal of breeding pigs is now based on 100 basic sows. The tillering index of the farm is 2.3 and the calculations are as follows: Boar: Under natural mating conditions, the ratio of normal sows should not exceed 1:20. The 100 basic sows need boar for 10020 = 5 heads. The number of updates per year is 52 = 2.5 headers (ie, 2 or 3 headers per year). Sows: According to an effective life cycle of 8 fetuses, with an average annual output of 2.3 fetuses per sow, the average service life of the sows is 82.3 = 3.48 ≈ 3.5 years. The annual elimination rate was 13.5100%=28.6%≈30%. The number of farms for 100 basic sows should be eliminated and the number of renewal should be 10030% = 30. The number of heads to be eliminated and renewed per month is 3012 = 2.5 (if a large-scale pig farm is used, the head of each week should be eliminated and updated. number). According to the general principle of the elimination of breeding pigs, the above data is updated as the theoretical calculation value. The actual operation should be based on the following principles to eliminate and update breeding pigs. The principle of elimination of sows: First, the elimination of age and weight have reached the breeding standards, but continue to raise 2 to 3 estrus after estrus estrus. Second, eliminate sows that are not estrus after 60 days after weaning. 3. Weed out sows that have returned 3 to 4 times continuously. 4. Weed out sows with less than 6 consecutive childbirths or fewer stillbirths and poor or poorly-divided sows. 5. Weeding out less than 6 pairs of nipples, abnormal development, sows with inverted titers or sucking tits or deputy nipples, and poor milking ability. 6. Weed out the sows with poor motherhood, viciousness, and low rate of rearing. 7. Weed out sows that are slow to eat, overweight and overweight, slow-moving, dull skin, and have no eyes. VIII. Elimination of sows with deformed offspring. Nine, eliminate sows that have diseases or disabilities, older age, and decreased performance. The elimination principle of boars is generally eliminated based on the age of use, but boars that are bulky, poor in semen quality, poor in mating performance, and violent in temperament should be eliminated in time. After the elimination of vacancies, they should be filled with ideal spare breeders at any time.
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