Estimation of genetic parameters for body weight and ten body measurements at different age stages in Breton and Percheron horses

Abstract

We estimated the genetic parameters for body weight and ten measurements (height at withers, height at croup, body length, chest depth, chest width, hip width, croup width, rump length, chest girth, and cannon bone circumference) at different ages in Breton and Percheron horses. Data included 307 Breton and 324 Percheron horses born between 1999 and 2011 at the Tokachi Station, National Livestock Breeding Center, Japan. The animals were measured every two months on average. Three age groups (birth to 6 months for stage 1, 7 to 19 months for stage 2, and 20 to 34 months for stage 3) were defined. Each stage was treated as a different character and a three-trait animal model was applied for the estimation of variance components. Heritabilities for Breton for each stage ranged from 0.05 to 0.36, 0.16 to 0.54, and 0.08 to 0.66, and 0.05 to 0.38, 0.03 to 0.76, and 0.23 to 0.84 for Percheron. Genetic correlations between stages were all positive in both breeds and ranged from 0.37 to 1.00.

Maternal effect on first‐year growth of Hokkaido native foals kept outdoors all year round

“…Maternal effects on early growth have been reported in animals such as beef cattle and sheep (Meyer, 1992; Safari et al, 2005). The existence of maternal effect, mainly derived from dam milk in addition to direct genetic effects (Hintz et al, 1978) and environmental factors (Yamamoto et al, 1993), has also been suggested in horses (Masuda et al, 2014; Yamamoto et al, 1993); however, no reports have estimated this effect. The HKD tested in this study were managed on the farm in the same way for 28 years, and foals were reared with dams after birth without supplementary feeding until weaning.…”

“…As foals are usually reared with their dams until weaning, maternal effects associated with dam lactation may influence foal growth during this period. Therefore, maternal effects should also be considered with direct genetic effects when analyzing data on foal growth (Masuda et al, 2014).…”

“…Factors such as the age and weight of the dam (Hintz et al, 1979; Wilsher & Allen, 2003; Yamamoto et al, 1993) and weaning (Kavazis & Ott, 2003; Rogers et al, 2004; Warren et al, 1998) are reported to affect the early growth of the foal. Direct genetic effects (Hintz et al, 1978; Masuda et al, 2014), breeding seasons (Hintz et al, 1979; Pagan et al, 1996, 2009), and feeding management (Morel et al, 2007) also affect foal growth. As foals are usually reared with their dams until weaning, maternal effects associated with dam lactation may influence foal growth during this period.…”