12.3.1.3 Evaluation and inbreeding (2024)
- Tessa Jacobs
- Kor Oldenbroek
In a closed population such as that of the KFPS, inbreeding plays an important role in the breeding policy. Inbreeding within the population of Friesian horses has increased too much in recent decades.
Members are advised by the KFPS to avoid close inbreeding when making matings. As an aid, it is indicated that the inbreeding coefficient of a combination should not exceed 5%. This inbreeding coefficient is calculated in a pedigree consisting of 5 generations. In fact, this results in an underestimation of reality, calculated over all known generations, sometimes up to the establishment of the herdbook in 1879, the inbreeding percentage is much higher.
The KFPS uses two instruments to limit the increase in inbreeding at a population level. In the first place, stud restrictions or mating quota (i.e. stallions may get a maximum number of foals) are applied to limit the influence of individual stallions. In addition, the relatedness percentage is used in the stallion selection. The relatedness percentage indicates the degree of relatedness to the population. Stallions with a low relatedness percentage have an advantage in being approved. The KFPS aims for an increase in inbreeding in the population of less than 1% per generation.
In 2023 the KFPS funded a large research project to use genomics to identify the circulating recessive disorders and their carriers. See chapter 7.7.1.1.