Genetic and Environmental Influences on Semen Traits in A.I. Bulls

Abstract

Contents: Repeatability and heritability coefficients were estimated for ejaculate volume, mass movement, individual motility, sperm concentration, first and second post‐freezing control of motility, number of doses frozen, total number of spermatozoa and total number of motile spermatozoa per ejaculate in the first ten ejaculates of 175 Swiss Holstein and 673 Simmental young bulls (200 pure Simmental, 473 Simmental x Red Holstein crosses). Data were analysed using the univariate individual animal model with effects of interval between consecutive collections, age of bull at collection, season of collection, breed group of Simmental bulls according to percentage of Red Holstein genes, bull (within breed group) and permanent environment. Crossbred bulls had a better performance in all traits. Repeatability coefficients ranged from 0.28 to 0.46. They indicate that the prediction of semen quality in young bulls of the Swiss Holstein and the Simmental breed is possible to some extent. Heritabilities in Swiss Holstein bulls were generally very low and did usually not exceed 0.10, but standard errors of these estimates were high. Relatively high heritabilities (0.18–0.30) were found for Simmental bulls, Differences in heritabilities between these two breed groups were probably a consequence of the low number of Swiss Holstein bulls.

Genetic Parameters for Semen Production Traits in Austrian Dual‐Purpose Simmental Bulls

“…Heritabilities for ejaculate volume and total number of spermatozoa found in this study were comparable with those estimated by Makulska et al. (1993) for Simmental bulls with heritabilities of 0.19 and 0.20, respectively.…”

Genetic parameters for semen production traits in Swiss dairy bulls

“…The repeatability coefficients varied between 0.44 and 0.74 (Table ) and as such represent significantly higher values than those reported by Makulska et al () for Swiss Holstein and Simmental bulls (0.28–0.46). There is little variability among breeds in repeatability of sperm concentration trait (0.44–0.53).…”

“…In other studies, average values in the range of 3.07–7.95 ml for volume, 980–6,961 × 10 6 /ml for concentration and 51%–78.21% motility were reported (Druet et al, ; Ducrocq & Humblot, ; Kealey et al, ; Mathevon et al, ; Paldusová, Kopec, Filipčík, Hošek, & Máchal, ; Stålhammar, Janson, & Philipsson, ). In the case of the Swiss Holstein and Simmental bulls, Makulska et al () found very similar values for volume (HO = 4.10; SI = 4.28 ml), and somewhat lower values for concentrations (HO = 1,077.2; SI = 1,100.1 × 10 6 /ml) and for sperm motility (HO = 74.7%; SI = 74.3%).…”

“…For this reason, a multitude of tests on sperm traits, such as volume, concentration, motility and morphological anomalies, is carried out by insemination organizations. It was shown in other/various studies that sperm and ejaculate traits are influenced by a great number of genetic and environmental factors (Fuerst‐Waltl, Schwarzenbacher, Perner, & Sölkner, ; Gredler, Fuerst, Fuerst‐Waltl, Schwarzenbacher, & Sölkner, ; Kealey, MacNeil, Tess, Geary, & Bellows, ; Makulska, Hagger, Kuenzi, & Kupferschmied, ; Mathevon, Buhr, & Dekkers, ). The latest variance components (VC) for Swiss Holstein and Simmental bulls were assessed by Makulska et al ().…”

Computing marginal posterior densities of genetic parameters of a multiple trait animal model using Laplace approximation or Gibbs sampling

“…This is an inverse Wishart distribution with n+v R degrees of freedom and scale matrix V R + S e . Sorensen (1996) (Ouali, 1984;Taylor et al, 1985;Makulska et al, 1993). …”