Cow selection should pay attention to the following points: 1. The stability of the selected target. After the selection of the target is set, it is necessary to adhere to the implementation and maintain relative stability. 2. The accuracy of the selection basis. The selection effect depends to a large extent on whether the dairy cow's archival data is complete, whether the metrics and records of various phenotypic values ​​are true and reliable, and at the same time, it depends on what method is selected and what kind of data is selected. 3. The heritability of traits is genetically related. The heritability of the selected traits directly affects the selection effect, and the genetic correlation between the traits has a greater impact on the selection effect. 4. Select the difference and the selection strength. If the ratio of seed retention is small and the degree of variation is large, then the greater the selection difference and the selection intensity, the better the effect of seed selection. 5. Generation intervals. Dairy cows are usually separated by 5 years. This length of time affects the speed of improvement and the breeding process, so measures must be taken to shorten the generational interval. 6. The number of selectable forms. The selected traits should focus on the key, not too much. 7. Environment. The phenotypic value of any quantitative trait is the result of both genetic and environmental factors. The environmental conditions change and the phenotypic values ​​change accordingly. squid Head Squid Head,Calamari Heads,Cuttlefish Head,Head Squid ZHEJIANG EVERNEW SEAFOOD CO.,LTD , https://www.evernewseafood.com