Analysis of Czech cold-blooded horses: genetic parameters, breeding value and the influence of inbreeding depression on linear description of conformation and type characters

Abstract

Genetic parameters, breeding values and inbreeding depression for 22 linear type description of conformation and type characters and 4 body measurements were evaluated in a group of 1744 horses of three original cold-blooded breeds in the Czech Republic in a long period of 18 years (1990)(1991)(1992)(1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007). Based on the values of Akaike's information criterion, residual variance and heritability coefficient, a model with fixed effects (sex, year of description, breed, and classifier) and with a random effect (animal) was selected. Heritability coefficients for the particular traits were in the range of 0.11 to 0.55 and genetic correlations ranged from -0.63 to 0.97. Inbreeding depression, expressed as coefficients of regression on one percent of inbreeding, was in the range of -0.0992 to 0.0242 points for the particular traits. The inclusion of inbreeding depression in the model resulted in a moderate change in h 2 in one-third of the traits. In two-thirds of traits, the value of r G increased or decreased by 0.01. Standard deviations of the breeding values for linear type description of conformation and type characters were in the range of 0.30 to 0.72 and 0.62 to 6.18 for body measurement traits. Among breeding values estimated by a model without inbreeding depression and a model with inbreeding depression, Spearman's rank correlation coefficient values for the particular traits were 0.916-0.999 (sample of all horses), 0.710-0.992 (10% of the best horses) and 0.827-0.998 (10% of the worst horses). If the average value of the inbreeding coefficient is low (0.03), then it is not necessary to include the influence of inbreeding depression in the model for the genetic evaluation of individuals of original cold-blooded horses kept in the Czech Republic.

Genetic parameters estimation and breeding values prediction for linear described traits in the Old Kladruber horse

“…Vostrý et al (2011a) found average values of the inbreeding coefficient (F X ) to be 7.3% in the Old Kladruber horse. Similar results were published by Vostrý et al (2011b) on Czech cold-blooded breeds of horses.…”

Selection for morphology, gaits and functional traits in Lusitano horses: II. Fixed effects, genetic trends and selection in retrospect

“…In our study, inbreeding depression was observed for nearly all the morphological and gait traits analyzed, but its effects on functionality were negligible. For HW, the observed effect of inbreeding was similar to that reported by Vostry et al (2011) for Czech cold-blooded horses, but much lower than the value reported by Gomez et al (2009) for the Andalusian horse. For morphological traits, where we estimated negative consequences of inbreeding, there is no clear pattern established for other horse breeds, such that significant inbreeding depression has been reported in some studies (Gomez et al, 2009;Vostry et al, 2011) while other authors have found no appreciable effects of inbreeding (Curik et al, 2003;Sierszchulski et al, 2005;Wolc and Balinska, 2010).…”

“…For HW, the observed effect of inbreeding was similar to that reported by Vostry et al (2011) for Czech cold-blooded horses, but much lower than the value reported by Gomez et al (2009) for the Andalusian horse. For morphological traits, where we estimated negative consequences of inbreeding, there is no clear pattern established for other horse breeds, such that significant inbreeding depression has been reported in some studies (Gomez et al, 2009;Vostry et al, 2011) while other authors have found no appreciable effects of inbreeding (Curik et al, 2003;Sierszchulski et al, 2005;Wolc and Balinska, 2010). Nevertheless, it could be anticipated that the effect of inbreeding on morphological traits would be small, as these are expected to be less affected by inbreeding depression than fitness-related traits (DeRose and Roff, 1999).…”

“…Inbreeding in horses has been shown to have detrimental effects on racing performance (Klemetsdal, 1998), morphological traits (Gomez et al, 2009;Vostry et al, 2011), reproductive ability (Van Eldik et al, 2006;Sairanen et al, 2009) and increase the incidence of some pathologies (Curik et al, 2000;Sevinga et al, 2004). In our study, inbreeding depression was observed for nearly all the morphological and gait traits analyzed, but its effects on functionality were negligible.…”

Investigating a complex genotype-phenotype map for the development of methods to predict genetic values based on genome-wide marker data – a simulation study for the livestock perspective

“…head length and width or face width, Table 2) were also discriminative between males and females, allowing us to clearly distinguish between the two sexes. A relative comparison of PRMe population with other horse breeds indicates that they generally have a height at the wither greater than other horse breeds of a similar body weight, such as the Mangalarga Marchador horse (148.31 cm; Pinto et al 2008) or the Lipizzan horse (155.11 cm; Zechner et al 2001) and slightly higher than the Spanish Purebred horse (155-158 cm, Molina et al 1999, Gómez et al 2009) and Friesian horses (158.8; Pretorius et al 2004), but very similar to Czech cold-blooded horses (159.88; Vostrý et al 2011). Moreover, the body length of the Spanish Purebred was 159 cm (Gómez et al 2009) and for the Lipizzan horses it was 160.5 cm (Zechner et al 2001), which are both very similar to the PRMe (159 cm, Table 2).…”