Effect of Breed and Season in Buck Semen Cryopreservation: The Portuguese Animal Germplasm Bank.

The aims of this study were to characterize the semen as well as the influence of breed, season, and semen processing on spermatozoa (SPZ) traits of four native Portuguese goat breeds used for the bank of Portuguese animal germplasm (BPAG). A total of 1017 ejaculates from Serrana (n = 30), Bravia (n = 15), Charnequeira (n = 11), and Preta de Montezinho (n = 3) bucks were collected between 2004 and 2020 at (EZN-INIAV; 39° N) during the whole year under natural conditions. All the fresh and cryopreserved (-196 °C) semen was evaluated and stored in the BPAG.

Effect of In Vitro Addition of Melatonin and Glutathione on Seminal Parameters of Rams in Diluted Semen and after Thawing.

The present study aimed to evaluate the effects of melatonin (MLT), glutathione (GSH), and their combination on ram semen quality after thawing. During eight weekly sessions, semen from three Merino rams was pooled, diluted with an egg-yolk-based semen extender, and divided into four groups: control, 1 mM MLT, 5 mM GSH, and 1 mM MLT + 5 mM GSH. Diluted semen was evaluated before and after the freezing process.

Ram Semen Cryopreservation for Portuguese Native Breeds: Season and Breed Effects on Semen Quality Variation.

The semen quality is one of the determinant factors of ram semen cryopreservation. The present retrospective study aimed to characterize the seasonal ram pattern during the year for ten Portuguese local sheep breeds, hypothesizing that the breed and season had low effects on the main spermatozoa traits. A total of 1471 ejaculates were used and evaluated (fresh semen) from 85 rams between 2004 and 2020 and re-evaluated after thawing (thawed semen).

A Pilot Study on the Uptake of Propidium Iodide and YO-PRO-1 Iodide through the Pannexin Channels in Wallachian Frozen-Thawed Ram Spermatozoa.

Propidium iodide (PI) and YO-PRO-1 (YPI) dyes are routinely used to determine sperm viability in many livestock species. It is commonly accepted that these dyes penetrate only sperm cells with damaged plasma membranes. Recently, however, the mechanism of dye uptake unrelated to damaged plasma membranes, but instead related to pannexin channels in dog and stallion sperm cells was demonstrated.

Effects of Three Semen Extenders, Breeding Season Month and Freezing-Thawing Cycle on Spermatozoa Preservation of Portuguese Merino Sheep.

This study aimed to evaluate and compare the effect of three semen extenders (S-EXT) on 22 spermatozoa (SPZ) parameters (subjective and computer-assisted sperm analysis evaluations), before and after semen cryopreservation throughout different months of the breeding season in the Portuguese Merino breed. According to the multivariable model, the SPZ viability (alive %), kinetics subjective individual motility, total motility, total progressive motility and its subpopulations, and beat cross frequency) were higher in the egg yolk-based S-EXT improved by Estação Zootécnica National (Portugal) than in Ovixcell or Andromed extenders. All the differences were only observed in thawed semen, except for total motility and total progressive motility, in which Ovixcell also showed the poorest results on fresh semen.