Genetic variability in Hanoverian warmblood horses using pedigree analysis

¹ Institute for Animal Breeding and Genetics, University of Veterinary Medicine Hannover, Bünteweg 17p, 30559 Hannover, Germany

^* To whom correspondence should be addressed. E-mail: ottmar.distl{at}tiho-hannover.de.

	Abstract

The data set analyzed comprised a total of 310,109 Hanoverian warmblood horses in order to ascertain the genetic variability, coefficients of inbreeding, and gene contributions of foreign populations. The reference population contained all Hanoverian horses born from 1980 to 2000. In addition, Hanoverian stallions born from 1980 to 1995 and Hanoverian breeding mares from the birth years 1980 to 1995 with registered foals were also analyzed for the same genetic parameters. The average complete generation equivalent was about 8.43 for the reference population. The mean coefficient of inbreeding was 1.33%, 1.19%, and 1.29% for the reference population, stallions, and breeding mares, respectively. The effective number of founders was largest in stallions (364.3) and smallest in the reference population (244.9). The ratio between the effective number of founders and the effective number of ancestors was 3.15 for the reference population, 3.25 for the stallions, and 3.06 for the breeding mares. The effective population size in the Hanoverian warmblood reference population was 372.34. English Thoroughbreds contributed nearly 35% of the genes to the Hanoverian reference population and even slightly higher contributions (39%) to the stallions. Trakehner and Arab horses contributed about 8% and 2.7%, respectively, to the Hanoverian gene pool. The most important male ancestors were Aldermann I from the A/E line, Fling from the F/W line, and Absatz from the Trakehner line, whereas the breeding mare Costane had the highest contribution to the reference population, stallions, and breeding mares. From 1996 onwards, the stallions Weltmeyer and Donnerhall had the largest genetic impact on the Hanoverian horse population.

Key Words: effective population size, genetic diversity, Hanoverian, horse, inbreeding