Coefficients of relationship and inbreeding among Finnish Ayrshire and Holstein-Friesian

Abstract

Pedigree data from national breeding value evaluations were used in calculation of the coeffi cient and rate of inbreeding, average coeffi cient and rate of relationship and generation intervals for the Finnish Ayrshire and Holstein-Friesian dairy cattle populations. The data had 1,366,555 Ayrshire and 377,869 Holstein-Friesian animals. The mean coeffi cient of inbreeding for Ayrshire and Holstein-Friesian animals born in the 1990s was 2.29% and 0.90%, respectively, and the trend was towards higher inbreeding values. The average coeffi cient of relationship, mean increase in inbreeding and generation interval was calculated for bulls born between 1976 and 1999, and for cows born between 1986 and 1999. The mean coeffi cient of relationship of Ayrshire bulls increased 2.22 %-units per generation and inbreeding increased 0.20 %-units per generation during the years studied. The mean coeffi cient of relationship of Finnish Holstein-Friesian bulls increased 0.96 %-units per generation and inbreeding 0.17 %-units per generation. The mean coeffi cient of relationship and inbreeding of Ayrshire cows increased 0.38 %-units and 0.31 %-units per generation, respectively. For Holstein-Friesian cows the mean coeffi cient of relationship and inbreeding increased 0.25 %-units and 0.11 %-units per generation, respectively. Results show that inbreeding is low and it is increasing slowly in both breeds. However, especially the coeffi cients of relationship of Ayrshire bulls are high in some age classes and this may lead into faster increase in coeffi cients of inbreeding.

Pedigree analysis of the Afrikaner cattle breed

“…In addition, genetic variation will ensure a capacity for long-term response to selection pressures, either through artificial or natural selection (Frankham, Ballou and Briscoe, 2002). Additionally, Vahlsten, Mäntysaari and Strandén (2004) emphasized the importance of monitoring the level and rate of inbreeding within a population across time. The reduction of genetic variability in beef cattle has been researched extensively (e.g.…”

A selective genotyping approach identifies QTL in a simulated population

“…The additive relationship values of each of the selected tails, for each trait, were very similar to each other's, ranging from 4.26 to 4.37 %; but they were higher than the corresponding value calculated for the whole population (3.01%). To appraise the extent of the difference in the average relationship between the tails and the whole population, it is useful to cite Vahlsten et al [ 16 ] who reported that an increase by 0.96 % units of relationship, per generation, is to be considered slow, this value referring to Friesian bulls, born during 40 years, and belonging to a population of over 400,000 animals. It can therefore be inferred that the relationship differences observed in the present study reproduce the mere generational trend.…”