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Testosterone serum profile, semen characteristics and testicular biometry of Mangalarga Marchador stallions in a tropical environment
Author(s) -
Waddington B,
PenitenteFilho JM,
Neves JGS,
Pinho RO,
Chaya AY,
Maitan PP,
Silveira CO,
Neves MG,
Guimarães SEF,
Carvalho GR,
Guimarães JD
Publication year - 2017
Publication title -
reproduction in domestic animals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.546
H-Index - 66
eISSN - 1439-0531
pISSN - 0936-6768
DOI - 10.1111/rda.12918
Subject(s) - biology , semen , sperm , testosterone (patch) , seasonal breeder , reproduction , sperm motility , zoology , endocrinology , ecology , anatomy , botany
Contents This study was conducted to characterize the daily profile of testosterone secretion and its mean concentrations in the four seasons as well as to evaluate the semen characteristics and testicular biometry of Mangalarga Marchador stallions throughout the year in a tropical region. Three stallions were submitted to semen collections and evaluation of testicular biometry every 14 days along a year. Blood samples were collected once at the middle of each season, in a 20‐min interval during 24 hr in order to evaluate the testosterone secretion profiles among seasons. Testosterone concentrations along the day were higher at the beginning of the afternoon (from 12:00 to 15:00 hr), but a circadian secretion was not clearly observed. Mean testosterone concentrations did not differ among seasons ( p > .05), but a pattern of secretion along the day showed variations with higher concentrations in the afternoon during the winter. Ejaculate volume was higher during summer; however, sperm motility decreased in summer and spring. Total sperm in ejaculate, sperm morphology and testicular biometry kept constant along the year showing no differences among the seasons. The results demonstrated that in a tropical region, reproductive aspects of stallions did not show a clearly defined seasonal variation, and months of autumn and winter were not unsuitable for reproduction of the males.