Influence of seasonal differences on semen quality and subsequent embryo development of Belgian Blue bulls

Abstract

Belgian Blue bulls are more susceptible to high temperature and humidity index (THI) than most other cattle breeds. Here, we investigated whether high ambient temperature during summer affected semen quality and subsequent embryo development in Belgian Blue cattle. For this purpose, semen samples were collected from six healthy mature Belgian Blue bulls in March (Low THI group; THI between 30.6 and 56.4) and August 2016 (High THI group; maximum THI of 83.7 during meiotic and spermiogenic stages of spermatogenesis; 14–28 days prior to semen collection) respectively. Motility, morphology, acrosome integrity, chromatin condensation, viability, and reactive oxygen species production were assessed for frozen-thawed semen. Moreover, the efficiency of blastocyst production from the frozen-thawed semen samples of the two groups was determined in vitro . Blastocyst quality was determined by assessing inner cell mass ratio and apoptotic cell ratio. Fresh ejaculates showed a higher sperm concentration in low THI when compared to the high THI group ( P ≤ 0.05), whereas semen volume, subjective motility, and total sperm output were not affected ( P > 0.05). In frozen-thawed semen, total and progressive motility, viability, and straight-line velocity were lower in high THI compared to the low THI group ( P < 0.05), while H 2 O 2 concentration, aberrant chromatin condensation, and abnormal spermatozoa were higher in the high THI group ( P < 0.05). Blastocyst rates were significantly higher when low THI samples were used ( P < 0.05). Moreover, the total cell number and trophectoderm cells were significantly higher ( P < 0.05) in blastocysts derived from low THI samples, whereas the apoptotic cell ratio was significantly higher ( P < 0.01) in blastocysts derived from high THI spermatozoa. In summary, our data show that elevated ambient temperature and humidity during summer can decrease the quality of frozen-thawed spermatozoa in Belgian Blue bulls and also affect subsequent embryo development.

Seasonal variations in semen traits of exotic cattle bulls of different age groups in the subtropical region

“…25 Meanwhile, Bhakat et al 24 published that semen concentration increased as the bull's age increased. A concurring report by Netherton et al 9 indicates good quality sperm in summer, whereas a contradictory report by Seifi-Jamadi et al 20 states that sperm concentration is lower in bulls that undergo exposure to summer heat stress. The young bull group's number of sperms per ejaculate values was 29.40% higher than those of the adult bull group.…”

“…16 Normal and fertile spermatozoa can only be formed when the testes are 2 to 5°C below body temperature, which makes temperature an essential parameter for both normal testicular function and spermatozoa production. 17,18 According to Sabes-Alsina et al 19 and Seifi-Jamadi et al, 20 there may be changes in semen samples obtained after the spermatogenetic period due to temperature changes in the testis. The increased relative humidity and temperature may harm spermatogenesis and luteinizing hormone secretion.…”

Determination of double- and single-stranded DNA breaks in bovine sperm is predictive of their fertilizing capacity

“…In this regard, and although selecting sires on the basis of their artificial insemination outcomes appears to be the best approach, it is obvious that it is not an efficient way of choosing animals, because: a) it is time consuming, and b) when reproductive data are available, the animal is older, and age is known to be detrimental on sperm quality [ 62 ]. In addition, it is well known that sperm functional parameters may change in relation to the season when semen is collected [ 63 , 64 ], and this may generate a bias between samples used for sperm quality analysis and those used for fertilization. In our study, we could not obtain samples throughout the year, but we conducted analyses in pools of three ejaculates collected in 5-week periods, ensuring that each pool contained ejaculates obtained in at least two seasons.…”

Shade availability on pasture does not affect semen characteristics of Brahman bulls (Bos taurus indicus)

“…The physiological consequences of heat stress in males are often studied by increasing testicular temperature, which is usually induced artificially, for example, by scrotal bags or insulation ( Garcia-Oliveros et al, 2020 ; Newton et al, 2009 ; Rahman et al, 2011 ) or using hot rooms or heating semen ( Peña Junior et al, 2021 ); hence, naturally high environmental temperatures have also been shown to disrupt the male reproductive physiology in the different species ( Li et al, 2020 ; Rasooli et al, 2010 ; Seifi-Jamadi et al, 2020 ). Once heat stress in animals leading to reproductive failure may occur when high environmental temperatures can no longer be adjusted by the body and its compensatory physiological mechanisms ( Kastelic et al, 1997 ), the in situ studies of the process may lead to more robust and physiological outcomes and insights on which the environment itself influences parameters.…”

“…It has been shown and discussed that different heat stress conditions (for example, induced or natural exposure, as well as mild or severe stress) may lead to different outcomes; for example, mild and moderate heat stress may show adverse effects on sperm and fertility in mice and farm animals more susceptible to high temperatures ( Rizzoto et al, 2020 ; Seifi-Jamadi et al, 2020 ); whereas the called “adapted” animals in hot and humid climates may not exhibit any difference in sperm evaluation of fertility throughout the year (reviewed in Morrell, 2020 ; Rasooli et al, 2010 ).…”