Problems easily overlooked in the process of selecting and retaining reserve pigs

(1) the selection and retention procedure is unreasonable and the selection and retention process is simplified: in some pig farms, the selection and retention process of reserve pigs is very simple, and there is no fixed procedure, but after a simple evaluation of breeding pigs, they can be selected and retained. This can easily lead to an imbalance in blood selection and retention and a decline in the production performance of breeding pigs. Therefore, the selection of reserve pigs should have a fixed procedure to rely on. Generally, the selection and retention of reserve pigs should go through three processes: primary selection, medium selection and selection. When the primary selection is transferred from the litter stage to the breeding stage, the waiting group with 4 times the amount of breeding is determined; the medium selection means that when Zi Pei turns to fattening and fattening, 50% of the individuals are selected from the waiting group to be selected as the reserve group; the final selection refers to the selection of excellent individuals to determine the reserve pig herd according to the test results. Each stage has different selection criteria, the primary selection is mainly based on the measured results of the ancestors, as well as some traits that the individual can express, such as the individual is more important than 1.2kg, the number of nipples is more than 7 pairs and neatly arranged, there are no blind nipples, sunken nipples, etc., and the whole sibling does not have genetic diseases; the successful selection mainly depends on the growth rate and physical appearance. The selection standard is to combine the above measured data with the test results to calculate the comprehensive index of breeder pigs. The daily gain and backfat thickness of 30~100kg are more than 120% of the average level, and the patrilineal index and maternal index are more than 100%. Only in strict accordance with certain procedures for reserve selection and retention, can the blindness of selection be avoided and the production level of the whole population be improved.

(2) relying too much on the performance test results and neglecting the choice of body shape and appearance. Although the performance test is important in the process of reserve selection and retention, the evaluation of body shape and appearance can not be ignored. Only a strong physique and a compact structure can maintain its normal reproductive function, and there is a strong correlation between some somatotype traits and production performance. For example, it has been reported that the correlation between the curvature of the forelimb and the growth rate is 0.44, such as selecting individuals with normal development of the forelimb. Its growth rate will also increase quickly. Individuals with compact body structure and strong physique will also be used for longer years. Sows with poor sports performance such as Grindflok have less than 21% of the fourth fetus in the herd, so when selecting reserve individuals, we must pay attention to the development of their limbs, observe the coordination of exercise, and evaluate the compactness of physical structure. In addition, the number of nipples is also an important somatotype trait. In the process of reserve selection, it is necessary to ensure that the effective nipple number of reserve sows is more than 7 pairs, the distance between nipples is uniform, and there are no blind nipples, sunken nipples and volcanic nipples.