Assessment of field fertility and several in vitro sperm characteristics following the use of different Angus sires in a timed-AI program with suckled Nelore cows

In order to provide information that may help researchers to understand the main cause(s) of differences in bull fertility frequently observed in field trials, this study aimed to investigate conception rates as well as several in vitro sperm characteristics of different sires of unknown fertility u...

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Bibliographic Details
Published in:Livestock science 2012-06, Vol.146 (1), p.38-46
Main Authors: Oliveira, Letícia Zoccolaro, de Arruda, Rubens Paes, de Andrade, André Furugen Cesar, Celeghini, Eneiva Carla Carvalho, dos Santos, Ricarda Maria, Beletti, Marcelo Emílio, Peres, Rogério Fonseca Guimarães, Oliveira, Clara Slade, Hossepian de Lima, Vera Fernanda Martins
Format: Article
Language:English
Subjects:
Angus
body condition
Bull fertility
bulls
conception
Conception rate
cows
field experimentation
lipid peroxidation
Nellore
pregnancy
pregnancy diagnosis
researchers
semen
sires
Sperm characteristics
spermatozoa
technicians
thawing
Timed-AI
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Summary:In order to provide information that may help researchers to understand the main cause(s) of differences in bull fertility frequently observed in field trials, this study aimed to investigate conception rates as well as several in vitro sperm characteristics of different sires of unknown fertility utilized in a Timed-AI (TAI) program. Suckled Nelore cows submitted to the same TAI protocol were allocated into eight breeding groups of approximately 120 animals each. Frozen semen doses from three Angus bulls and three different batches from each bull were utilized. Approximately 100 doses from each batch were used in TAI. Sires, batches and AI technicians were equally distributed across breeding groups. Cows were examined for pregnancy diagnosis 40d after TAI. For in vitro sperm analyses, the same thawing procedure was repeated in the laboratory to mimic field conditions. The following in vitro sperm characteristics were assessed: computerized motility, thermal resistance, plasma and acrosomal membrane integrity, lipid peroxidation, morphology, morphometry and chromatin structure. No effect of breeding group, body condition score, AI technician and sire was observed. However, some significant differences among bulls were detected in laboratory analyses. Semen from sire presenting numerically lower (P>0.05) pregnancy/AI also presented lower (P
ISSN:1871-1413
1878-0490
DOI:10.1016/j.livsci.2012.02.018