Sperm transport into the oviducts of heifers mated early in oestrus

Wilmut, Ian; Hunter, Richard

doi:10.1051/rnd:19840411

Cited by 78 publications

(34 citation statements)

References 22 publications

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“…Following preliminary observations in rabbits (Harper, 1973a,b) and bats (Racey et al, 1975;Racey, 1979) and detailed surgical studies in sheep (Hunter et al, 1980Nichol, 1983, 1986), pigs (Hunter, 1981(Hunter, , 1984 and cows Wilmut, 1982, 1984;Wilmut and Hunter, 1984), the caudaldistal-portion of the oviduct isthmus was recognised as a significant pre-ovulatory reservoir for viable spermatozoa, even though substantial sperm populations might still be found in lower regions of the tract. The term functional sperm reservoir was therefore proposed for the caudal isthmus since it represents the region from which fertilising spermatozoa are released close to the time of ovulation (Hunter et al, 1980;Hunter, 1981).…”

Section: Functional Sperm Reservoirmentioning

confidence: 99%

Sperm release from oviduct epithelial binding is controlled hormonally by peri‐ovulatory graafian follicles

Hunter

2007

Molecular Reproduction Devel

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To avoid inappropriate conclusions being drawn from the extensive use of in vitro preparations of sperm-oviduct epithelial binding, it is recalled that events in the genital tract of mammals are regulated by the gonads, primarily by their changing secretion of steroid hormones. Key observations from in vivo models are used to emphasise the dynamic interactions between viable sperm cells and the caudal (distal) portion of the oviduct isthmus, the site of the functional sperm reservoir. These include (1) preovulatory arrest and epithelial binding of intact sperm cells and thereby suppression of completion of capacitation, (2) peri-ovulatory activation and release from binding of discrete sub-populations of competent spermatozoa, and (3) post-ovulatory liberation of large numbers of spermatozoa. These observations underline the influence of endocrine regulation of sperm binding and release by peri-ovulatory Graafian follicles, a point brought out by the enhanced sperm release prompted by diverse treatments with solutions of progesterone. In the light of this evidence, the suitability of in vitro preparations for clarifying physiological events should be questioned, especially if myosalpingeal catecholamines diffusing out of the autonomic nervous system contribute to sperm activation and/or release. None of this is to infer that sperm cells themselves are without influence on their epithelial binding reaction(s). Nor is it to suggest that in vitro models of sperm-oviduct binding are without relevance to the development of sperm evaluation technologies. However, pre-ovulatory sperm-epithelial binding and a regulated peri-ovulatory release should be seen as vital tactics in the overall strategy of achieving successful monospermic fertilisation. Mol. Reprod. Dev. 75: 167-174, 2008.

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Section: Functional Sperm Reservoirmentioning

confidence: 99%

Sperm release from oviduct epithelial binding is controlled hormonally by peri‐ovulatory graafian follicles

Hunter

2007

Molecular Reproduction Devel

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“…In contrast to the marsupials and insectivores, most other species of mammals create an oviductal sperm storage reservoir by binding the sperm to the epithelial surface (Harper, 1973, Hunter, 1981Hunter and Nichol, 1983;Overstreet and Cooper, 1978;Suarez, 1987;Wilmut and Hunter, 1984;Yanagimachi and Chang, 1963). There are no specific structures like crypts; however, many of the bound sperm are found down in pockets formed by mucosal folds (Fig.…”

Section: Formation Of the Oviductal Sperm Storage Reservoirmentioning

confidence: 99%

Regulation of sperm storage and movement in the mammalian oviduct

2008

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The oviduct plays a vital role in ensuring successful fertilization and normal early embryonic development. The male inseminates many thousands or even millions of sperm, but this alone does not ensure that fertilization will be successful. The female tract, particularly the oviduct, provides filters that select for normal vigorously motile sperm. In conjunction with molecules in the seminal plasma and on sperm, the female tract regulates how and when sperm pass though the tract to reach the site of fertilization. Various regulatory processes control sperm passage into and through the oviduct. In some species, the uterotubal junction opens and closes to regulate when sperm may enter; furthermore, passage through the junction requires certain proteins on the sperm surface. Most of the sperm that manage to enter the oviduct soon become trapped and held in a reservoir. In marsupials and insectivores, this involves trapping sperm in mucosal crypts; while in most other mammalian species, this involves binding sperm to the oviductal epithelium. As the time of ovulation approaches, the sperm in the reservoir undergo capacitation, including motility hyperactivation. Capacitating sperm shed proteins that bind them to the mucosal epithelium, while hyperactivation assists the sperm in pulling off of the epithelium and escaping out of mucosal pockets. The process of sperm release is gradual, reducing chances of polyspermic fertilization. Released sperm may be guided towards the oocyte by secretions of the oviduct, cumulus cells, or oocyte. Hyperactivation likely assists sperm in penetrating the cumulus matrix and is absolutely required for penetrating the oocyte zona pellucida and achieving fertilization. KEY WORDS: sperm, fallopian tube, uterine tube, oviductThe oviduct consists of three segments, each with different functions: the uterotubal junction, the isthmus, and the ampulla. The uterotubal junction provides a barrier to infectious microbes that might enter the oviduct from the uterus. It also regulates which sperm may enter and when. The isthmus serves as a sperm storage organ and the ampulla provides an environment conducive to fertilization and early embryonic development. The movements of sperm are regulated by these three segments in different ways so as to fulfill those functions. The uterotubal junction regulates sperm movement from uterus to oviductThe anatomy of the uterotubal junction indicates that it is constructed to restrict entry of infectious organisms and leukocytes from the uterus and to regulate entry of sperm (Fig. 1A). In many species, mucosal folds fill most of the lumen and these folds Int.

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“…The mean interval from AI to ovulation when inseminating based on activity using an activity monitoring system was 7.9 h (Figure 4; Valenza et al, 2012). This may initially seem appropriate because it allows for the 6 to 8 h required for the sustained phase of sperm transport to the site of fertilization and sperm capacitation (Hunter and Wilmut, 1983;Wilmut and Hunter, 1984), however, the degree of variation in the AI to ovulation interval is a major concern for pregnancy outcomes to AI based on activity. Overall, 21% of cows received AI between 0 and 12 h after ovulation (Figure 4), a timing associated with low fertilization rates and embryo quality in lactating dairy cows (Roelofs et al, 2006), possibly due to aging of the oocyte.…”

Section: Timing Of Ai Relative To Behavioral Estrusmentioning

confidence: 99%

Expression and detection of estrus in dairy cows: the role of new technologies

Fricke

Carvalho

Giordano

et al. 2014

Animal

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Despite the widespread adoption of hormonal synchronization protocols that allow for timed artificial insemination (AI), detection of estrus plays an important role in the reproductive management program on most dairies in the United States. Increased physical activity is a secondary sign of estrus in dairy cattle, and a new generation of electronic systems that continuously monitor physical activity to predict timing of AI have been developed and marketed to the dairy industry. A variety of management and physiologic challenges inhibit detection of behavioral estrus on farms, but the prevalence of anouvular cows near the end of the voluntary waiting period is particularly problematic. Only 70% of lactating Holstein cows were detected in estrus when using an activity monitoring system, with the remaining 20% of cows classified as anovular and 10% ovulating without showing signs of activity. Mean time of AI in relation to ovulation based on the activity monitoring system was acceptable for most of the cows with increased activity, however, variability in the duration of estrus and timing of AI in relation to ovulation could result in poor pregnancy outcomes in some cows. Use of a Presynch-Ovsynch protocol for submission of cows for first AI has been widely adopted by dairies in the United States, and a combined approach in which AI based on activity is followed by submission of cows not detected with activity to timed AI after synchronization of ovulation may be an effective strategy for submission of cows to first AI. Based on a field trial on a large commercial dairy in the United States, the activity monitoring system detected 70% of cows with increased activity after the second PGF 2α injection of a Presynch-Ovsynch protocol, however, cows inseminated to increased activity had fewer pregnancies per AI (P/AI) compared with cows with increased activity after the second PGF 2α injection that received timed AI after completing the Presynch-Ovsynch protocol. Based on an economic model comparing reproductive management programs with varying levels of AI to estrus v. timed AI, the rate of estrus detection and the P/AI to inseminations based on AI to detected estrus v. timed AI affected the decision to inseminate based on activity v. timed AI. In conclusion, an activity monitoring system detected increased activity in about 70% of lactating Holstein cows on a large commercial dairy in the United States, however, synchronization of ovulation and timed AI was beneficial to inseminate cows not detected with increased activity by the activity monitoring system.

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Sperm transport into the oviducts of heifers mated early in oestrus

Abstract: Summary. An Introduction.

Cited by 78 publications

References 22 publications

Sperm release from oviduct epithelial binding is controlled hormonally by peri‐ovulatory graafian follicles

Sperm release from oviduct epithelial binding is controlled hormonally by peri‐ovulatory graafian follicles

Regulation of sperm storage and movement in the mammalian oviduct

Expression and detection of estrus in dairy cows: the role of new technologies

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