14.7.2.1 Optimal contributions of selected parents (2024)

For selection and mating in the nucleus of a dairy cattle breeding program the method of optimal contributions is developed (see chapter 9.11.1). It outweighs the breeding value of the sires and dams with the relatedness of the sires and dams with the average values in the nucleus. For each individual, the programs gives the number of matings that should be performed. The mating partners are paired according to their mutual relationship aiming at a low relationship between the animals of each pair. Outside the nucleus sires and dams are combined in a sire mating advice program. This program aims at compensatory matings: weak traits in the breeding value of the dam are compensated by strong traits in the breeding value of the sire.

For individual matings a practical directive is not to mate sires and dams that share common ancestors in three generations. This means that the average additive relationship between sires and dams is always lower than 6.25 % and the offspring will have an inbreeding coefficient lower than 6.25 %. And matings between carriers of the same recessive defect are not recommended in these mating programs.