When ejaculates from rival males compete for fertilization, there is strong selection for sperm traits that enhance fertilization success. Sperm quantity is one such trait, and numerous studies have demonstrated a positive association between sperm competition and both testes size and the number of sperm available for copulations. Sperm competition is also thought to favor increases in sperm qu...

fertility in the male is dependent on the proper production of sperm cells. this process, called spermatogenesis is very complex and involves the synchronization of numerous factors. the presence of pro–inflammatory cytokines, tumor necrosis factor-alpha (tnf–α), interleukin–1 alpha (il–1 α) and interleukin 1 beta (il–1 β) cytokines in the male reproductive tract (testis, epididymis and sperm) ...

The effects of miticides on the reproductive physiology of queens and drones were examined. The first study examined the effects of Apistan (fluvalinate), Check Mite+ (coumaphos), and Apilife VAR (74% thymol) on sperm production and viability in drones. Drones from colonies treated with each miticide were collected at sexual maturity. Sperm production was determined by counting the number of sp...

Kavak, A. 2004. Evaluation of sperm production, testicular measurements and post-thaw sperm quality in Tori and Estonian breed stallions. Licentiate dissertation.

The process of sperm production is well understood, but the studies of essential nutritional elements which are necessary for successful spermatogenesis are not deeply studied as yet. Our review focuses on integrating available information of various nutritional elements involved in spermatogenesis, sperm maturation and male reproductive system development, such as Zinc, Selenium, Folate, Vitam...

Sex preselection that is based on flow-cytometric measurement of sperm DNA content to enable sorting of X- from Y-chromosome-bearing sperm has proven reproducible at various locations and with many species at greater than 90% purity. Offspring of the predetermined sex in both domestic animals and human beings have been born using this technology since its introduction in 1989. The method involv...

Sperm competition is a potent postcopulatory selective force where sperm from rival males compete to fertilize a limited set of ova. Considering that sperm production is costly, we expect males to strategically allocate sperm in accordance with the level of competition. Accordingly, previous work has examined a male's strategic allocation in terms of sperm number. However, the seminal fluid pro...

The aim of our research was to examine the ability of density gradient preparation BoviPure and swim up method on bull sperm separation and in vitro embryo production (IVP) systems. Frozen/thawed semen from six Simmental bulls was pooled and treated using both methods. The sperm motility, concentration, membrane activity, membrane integrity and acrosomal status were evaluated and compared befor...

This study characterized seasonal changes in circulating LH and testosterone and in semen production and quality in the Northern pintail duck. Plasma LH and testosterone were measured in blood samples collected weekly throughout the year from eight males exposed to natural fluctuations in day length and temperature. Semen quality was evaluated weekly in these same males from April-June, the mon...