RT Journal Article
T1 Seasonal changes in testosterone and thyroxine concentrations in Mediterranean rams and bucks and their relationship with sperm cryoresistance
A1 Martínez Madrid, Carmen Belén
A1 Castaño, Cristina
A1 Ureña, Luis Pablo
A1 Flix, Elena
A1 Velázquez, Rosario
A1 López-Sebastián, Antonio
A1 Ungerfeld, Rodolfo
A1 Arrebola, Francisco A.
A1 Santiago-Moreno, Julián
AB This study examines the relationship between seasonal changes in plasma testosterone and thyroxine concentrations and the relationship between these changes and the sperm resistance to the freezing-thawing process in Merino x Merino Precoz crossbreed rams and Florida breed bucks. Plasma testosterone and thyroxine concentration, sperm head area, sperm variables and their cryoresistance ratios were analyzed throughout a year. Both species showed a rise in thyroxine preceding testosterone fall. Plasma thyroxine concentrations in rams were higher during autumn than in spring and summer (P<0.05), whereas testosterone concentrations were not influenced by season. Conversely, bucks showed seasonal differences in plasma testosterone levels, with higher concentrations during summer and autumn than winter and spring (P<0.05), whereas thyroxine concentrations were not influenced by season. In bucks, a negative correlation was detected between plasma testosterone concentrations and the cryoresistance ratio for membrane integrity (R=-0.88; P<0.05) from April to September and between plasma thyroxine concentrations and the cryoresistance ratios for total motility (R=-0.66; P<0.05), curvilinear velocity (R=-0.61; P<0.05), the amplitude of lateral head displacement (R=-0.77; P<0.05) and the beat-cross frequency (R=-0.74; P<0.05), throughout the year. The results suggest that the annual variation in sperm cryoresistance may be related to seasonal endocrine changes, at least in goat. Winter and spring are the most appropriate seasons to collect and freeze sperm from Florida goat
PB Elsevier
SN 1871-1413
YR 2021
FD 2021-04-20
LK https://hdl.handle.net/20.500.14352/93864
UL https://hdl.handle.net/20.500.14352/93864
LA eng
NO Martínez-Madrid B, Castaño C, Ureña LP, Flix E, Velázquez R, López-Sebastián A, Ungerfeld R, Arrebola FA, Santiago-Moreno J. Seasonal changes in testosterone and thyroxine concentrations in Mediterranean rams and bucks and their relationship with sperm cryoresistance. Livestock Science. 2021 Apr 20;249:104513
NO Beca predoctoral de LP financiada por fondos FEDER (PP.TRA.2016.0010 FEDER funds). Beca de colaboración de estudiantes de pregrado  de E Flix financiada por el Ministerio de Ciencia e Innovación.
NO Agencia Estatal de Investigación (AEI)
NO MCINN (AGL2017-85753-R. )
NO FEDER/UE (PP.TRA.2016.0010 fondos FEDER)
DS Docta Complutense
RD 7 abr 2025