Effect of thawing method on bull sperm survival in ejaculates frozen in 4 ml and 8 ml volumes  

Abstract

The aim of this study was to evaluate the effect of different thawing protocols (slow (P1), medium (P2), and fast (P3)) on percentage of motile sperm (MOT) and percentage of sperm cells with intact membranes (INT) in Holstein (4 bulls; 72 samples) and Czech Fleckvieh (4 bulls; 72 samples) semen frozen-thawed in 4 ml and 8 ml volumes. MOT was analysed in fresh semen, as well as immediately after thawing (T0) and 30 min after thawing (T30). INT was analysed using hypoosmotic swelling test (HOS test) in fresh ejaculate (FE), after diluting (DE), and at T0. The differences between FE parameters and frozen-thawed ejaculate parameters, expressing changes that occur during cryopreservation, were calculated. Apart from the effect of thawing protocol, the effect of breed and the effect of quality of FE expressed by MOT immediately after collecting were evaluated, too. Unlike thawing of semen cryopreserved in straws (0.25 and 0.5 ml), thawing using the slow protocol (P1) was the most appropriate (P < 0.05) for both observed volumes. There were found significantly higher MOT in the volume of 8 ml in both T0 and T30 and in the volume of 4 ml in T30 in samples thawed using P1 and P2. MOT in T0 was significantly affected by breed in samples frozen in 8 ml and in T30 in samples frozen in 4 and 8 ml. There were found no significant differences in INT in all reported volumes, however decrease of INT during cryopreservation was affected by breed.

Negative impact of heat stress on reproduction in cows: Animal husbandry and biotechnological viewpoints: A review

“…The negative effect of heat stress on the physiology of both male (bulls) and female (cows; heifers) reproduction has been described in a number of studies. The impact of the hot summer period on the reproduction of bulls is manifested mainly by a deterioration in sperm quality (Dolezalova et al 2016;Biniova et al 2018;Zubor et al 2020). Concerning female reproduction, an association between heat stress and ovarian activity, the number and quality of oocytes and transferable embryos can be probably reflected in other reproduction problems (Schuller et al 2017;Bezdicek et al 2019).…”

The Effects of Equilibration Time and Post-Thawing Temperatures in Cryopreservation of Gaga Chicken Semen

“…Cryopreservation causes thermal stress due to temperature changes during cooling, freezing, and thawing, and osmotic pressure due to cryoprotectant agents and crystallization in spermatozoa (Biniova et al, 2018;Khalil et al, 2018). Thawing semen quickly reduces the harmful effects of the recrystallization and hydration processes, preventing membrane damage to semen and cytoplasm.…”