Boar is the basis of pig breeding and the core of the whole pig production. Since the use of boar is limited, the natural mating boar is generally not more than 2 years, sows are not more than 8 nests, sperm collection boar can use 3 or 4 years, sows no more than 8 nests, and boar's individual production performance difference is big. Only the implementation of scientific and rational eliminate and update boar system can achieve the stability or improve the production level of boar to achieve the purpose of improving the economic efficiency of farms. So, how to eliminate and update the boar?
Calculated out the update of boar
Taking 100 sows as an example, the pig farrowing index is 2.3, calculated as follows:
Boar: In the natural mating conditions, generally the proportion of boars and sows should not exceed 1:20,so the 100 basic sows need 100 ÷ 20 = 5 boars. The annual update quantity of boar is 5 ÷ 2 = 2.5 (updated 2 or 3 boar).
Sows: According to an effective life cycle of breeding 8 nests, annual output of a sow is 2.3 nests, the sow's average life is 8 ÷ 2.3 = 3.48 ≈ 3.5 years. The annual elimination rate is 1 ÷ 3.5 × 100% = 28.6% ≈ 30%.
100 basic sows poggery should update 100 × 30% = 30 sows, the monthly eliminated and updated boars should be 30 ÷ 12 = 2.5 (in the large farms, should be calculated weekly quanitty of eliminated and updated).