Estudo de genética de população e endogamia em animais da raça Holandesa no estado do Paraná

Abstract

The objective of the present study was to evaluate the population structure and inbreeding of Holstein herds in the state of Paraná. The data used were provided by the Holstein Association of Paraná (APCBRH), which included a pedigree file of 206,796 animals born between 1970 and 2014. Results were obtained pertaining to pedigree integrity, complete pedigree, effective number of founders (f) and effective number of ancestors (fa), generation interval (GI), inbreeding coefficient (F), size effective population (Ne), mean ratio coefficient (CR), and number of progenies per breeder. The POPREP and ENDOG v.4.5 software were used to calculate the relevant population parameters and inbreeding. Based on the data set, the pedigree completeness presented animals with known relationship up to a sixth generation. The mean generation interval in the population was 6.3 years. For the average inbreeding coefficient, the result was 4.99%. Ne varied during the periods, ranging from 22 to 114, while the rate of inbreeding in these same periods showed a decreasing trend in the last years until 2014. The CR was estimated to be 0.71%. The effective number of founders (fe) was 418 animals and ancestors (fa) were 400 animals. In addition, the reproducers with the highest number of progenies in the population were identified. According to the level of inbreeding presented, it was observed that the dissemination of the genetic material of the main breeders between the generations, resulted in good indicators of genetic diversity, which allowed to propitiate a good genetic structuring of the herds, facilitating the conduction of the breeding programs genetic selection of the breed in the said state.