Influence of Seminal, Physical, and Mating Behavior Traits of Bulls on Number of Calves Sired per Bull in a Multisire Herd
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© 2008 American Registry of Professional Animal Scientists. A study was conducted to quantify the influence of behavior, physical characteristics, and seminal traits of bulls on reproductive performance in a multisireherd. Braunvieh (n = 6) and Bonsmara (n = 6) bulls (18 to 24 mo) were evaluated for BCS, social dominance rank (SDR), serving capacity, sperm motilityand morphology, and fertility-associate antigen classification of an ejaculate.Bulls (n = 12) were mated with multiparous cows (n = 305) for 90 d. Paternitywas verified by DNA typing. All bulls were fertility-associated antigen-positive. Bull breed, sperm motility and morphology, and SDR were associated with numberof calves sired per bull (P < 0.05, R2 = 0.75). More calves born early in the calving period (P < 0.025) were sired bybulls with = 80% normal sperm. Results indicate that assessment of SDR in con-junction with a breeding soundness exam can determine number of calvessired per bull. Furthermore, selection of bulls that produce at least 80% morphologicallynormal sperm may enhance thepercentage of cows impregnated early in the breeding season.
author list (cited authors)
Whitworth, W. A., Forrest, D. W., Sprott, L. R., Holloway, J. W., & Warrington, B. G.