Genetic parameters for linear type traits in Czech Holstein cattle

Abstract

A primary reason for collecting and utilizing information on type is to aid breeders in selecting profitable, functional cows in order that early culling for causes unrelated to yield (involuntary culling) can be avoided (Misztal et al., 1992). Selection on yield traits alone could decrease merit for traits with antagonistic genetic correlations with yield. Selection emphasis on type traits associated with increased herd life may be beneficial to decrease involuntary culling and increase profitability (Rogers and McDaniel, 1989). Conformation traits are recorded in many dairy cattle breeds (Foster et al., 1988;Harris et al., 1992;de Haas, et al., 2007). These traits have medium to high heritability (Meyer et al., 1987) and can often be recorded in a single assessment, which makes them reliable and relatively inexpensive traits that can be included in selection indices for overall merit (Schaeffer et al., 1985;Wiggans et al., 2004).The objective of this study was to estimate genetic parameters for currently recorded type traits and to utilize them in the genetic evaluation system and eventually in selection indices. These new estimates should provide improved accuracy of type evaluations, particularly for traits whose (co)variances have changed over time. MATERIAL AND METHODS Data collectionType classification records were extracted from the Czech-Moravian Breeder's Association official The objectives of this study were to estimate genetic parameters for 18 currently recorded linear conformation traits in Czech Holstein cattle. The data set consisted of 78 886 first-lactating Holstein cows. Traits, all scored on a 9-point scale, were fore udder attachment, rear udder height, udder depth, rear udder width, central ligament, teat length, front teat placement, rear teat position, stature, angularity, chest width, body depth, rump angle, rump width, rear legs rear view, rear leg set (side view), foot angle, and bone quality. Uni-and bivariate animal models were used. The models included fixed effects of herd-date of classification-classifier, classifier, and season of calving, quadratic regressions on age at calving and on days in milk and the random effect of animal. Heritability estimates obtained in univariate and in bivariate analyses were of similar magnitude. Heritabilities ranged from 0.17 to 0.32 for udder traits, 0.10 to 0.16 for foot and leg traits, and 0.18 to 0.45 for traits related to body size. Genetic correlations among the currently recorded linear traits ranged from -0.67 between foot angle and rear leg set (side view) to 0.75 between fore udder attachment and udder depth. Substantial genetic correlations were found for the following pairs of traits: rear udder height and rear udder width (0.70), chest width and body depth (0.69), front teat placement and rear teat position (0.68), angularity and bone quality (0.67). Corresponding phenotypic correlations for most pairs of traits were similar in direction but smaller in magnitude than the genetic correlations.

Genetic relationship between lactation persistency and conformation traits in Polish Holstein-Friesian cow population

“…The estimates of heritabilities of leg traits were consistent with those reported by Ptak et al (2011) and Zavadilova and Stipkova (2012), and lower than obtained by Misztal et al (1992), Berry et al (2004), Lassen and Mark (2008), and Nemcova et al (2011). All those results confirm that leg traits are strongly influenced by environmental conditions and rather difficult to improve by selection.…”

“…All those results confirm that leg traits are strongly influenced by environmental conditions and rather difficult to improve by selection. The estimates of heritabilities for udder traits were very close to those reported by Berry et al (2004) and Zavadilova and Stipkova (2012) but lower than those obtained by Lassen and Mark (2008) and Nemcova et al (2011). Berry et al (2004) reported higher heritability for chest width (0.26) and much higher for body depth (0.37).…”

“…Conformation was the first group of nonproduction traits scored and included in the selection indices for dairy cattle populations around the world (Misztal et al 1992;DeHaas et al 2007;Nemcova et al 2011;Ptak et al 2011). The main reason for collecting and using information on type traits in breeding programs is to select more profitable and functional cows.…”

“…Many type traits are strongly correlated with milk production traits as well as with other low-heritable functional traits, and for many decades selection for increased production has been accompanied by selection for better conformation. It is worth mentioning that selection for type traits associated with better herdlife may help decrease involuntary culling and increase profitability (Misztal et al 1992;Nemcova et al 2011).…”

Genetic Association Between Herd Survival and Linear Type Traits in Holstein Cows Under Tropical Conditions

“…The posterior mean of heritability for linear type traits obtained in conjunction with each measure of longevity (Long1_60, Long1_72, Long2_48 and Long2_54) showed low variation, which for the most part were 0.01 and 0.02 points, except for stature (0.04) and body depth, rump angle, foot angle and udder cleft that showed variation of 0.03 (Table 4). Low heritabilities for hoof angle (0.10) and udder texture (0.11) were also observed by Campos et al (2012) in Holstein cows, as well as by Němcová et al (2011) and Lagrotta et al (2010) in Holstein and Gir cattle, respectively, for hoof angle (0.09 and 0.12). The posterior residual correlations were low, ranging from -0.05 to 0.09 (Table 5).…”