1, the most basic requirement, according to the calculation that each fertile sow should provide at least 20 weaned piglets a year, the breeding ability of fertile sows should reach at least 500, and the renewal rate of general basic sows is about 25%. Therefore, with about 125 sows, about 625 sows should be raised;

2. Seasonal littering is concentrated in local hybridization, and each boar can meet the breeding needs of 25 ~ 30 fertile sows, requiring 18 ~ 20 breeding boars. If artificial insemination is carried out, each boar can meet the breeding needs of 50 ~ 60 sows, and at least 8 ~ 10 boars are needed. In production practice, the replacement rate of dead boars is also about 25%, so it is necessary to raise 4 ~ 5 spare boars.

3. In the production process, there should be about 6000 piglets and pigs in the same batch.

Therefore, a pig farm with an annual output of 1 1,000 pigs must have at least 6,650 pigs on hand.