Author(s): MOLINA, J. C. J.; SILVA, R. S. da; BIDEGAIN, F. A.; SOUZA, Y. B.; PURDY, P. H.; BLACKBURN, H. D.; AZEVEDO, H. C.

Summary: This study evaluated relationships among reproductive parameters and the bioclimatic indices: temperature and humidity index (THI), equivalent temperature index (ETI), black globe temperature and humidity index (BGTHI), and thermalv comfort index (TCI), during the frst 45 days of spermatogenesis (SP-45) and during the 15 days of sperm transit through the epididymis (STP-15) that preceded the reproductive assessments (ReA). Such information is useful in determining the optimal breeding season in Northeast Brazil. Santa Inês rams (n=25) underwent two ReA in three periods of the year (D-P=dry; R-P=rainy and RD-P=rainy/dry transition), and the bioclimatic indices were calculated at the corresponding SP-45 and STP-15 timepoints prior to each ReA. Sperm kinetic parameters in D-P were depressed compared to R-P and RD-P (P<0.05). The index values had an antagonistic relationship with most parameters and regression analysis demonstrated that the BGTHI and the TCI had a negative association with the progressive motility, curvilinear, straight line, and average path velocities, and a positive association with slow sperm in the ejaculate in SP-45 and STP-15 phases (P<0.01). Semen quality kinetics is afected throughout the year by the environment and it is apparent that it is impaired in D-P and better in R-P and RD-P seasons. The BGTHI and TCI measured in the sperm production phase classifed the environment most coherently and presented better association with the behavior of sperm kinetics.

Publication year: 2023

Types of publication: Journal article

Unit: Embrapa Coastal Tablelands

Keywords: Caprino, Carneiro, Recurso Genético, Santa Inês, Semen banks, Ships, Sêmen