Sperm Transport into the Cervix of the Ewe after Regulation of Estrus with Prostaglandin or Progestogen

Abstract

Mature ewes (12 per group) were given prostaglandin F20t (PG; 10 mg intramuscularly) on day 10 of an estrous cycle, to regress corpora lutea, or on day 16, after natural corpus luteum regression. Ewes treated on day 10 or 16 were in estrus on day 12 or 17, respectively. The PG-treated and untreated ewes were mated at estrus and necropsied 2 hr later. Sperm were counted in the oviducts, the uterus and the anterior, middle and posterior segments of the cervix. Sperm numbers were reduced in all three segments of the cervices of ewes treated with PG on day 10 but not in ewes treated on day 16. The results suggest that some factor associated with shortening of the estrous cycle inhibited sperm transport. Other ewes were treated with 60 mg of medroxyprogesterone acetate (MAP) by intravaginal sponge from day 6 to 14, 6 to 22 or 14 to 22 of an estrous cycle and mated at the ensuing estrus, 2 or 3 days after MAP withdrawal. Sperm numbers in the anterior cervix 2 hr after mating were reduced in all MAP-treated ewes, and sperm numbers in the entire cervix were significantly lower in the 6 to 14 day group than in the other MAP-treated ewes. In the ewes treated from day 6 to 14, endogenous progesterone secretion was similar to that of untreated ewes through day 14, and estrous cycles averaged 16.8 days in length. Thus, MAP treatment reduced sperm numbers in the cervix Mention of products or companies in this report does not constitute endorsement by the U.S. Department of Agriculture to the exclusion of others not mentioned. 2Reproduction Laboratory, Animal Physiology and Genetics Institue, Agricultural Research Center. 3The authors express appreciation to The Upjohn Company, Kalamazoo, Michigan, for supplying the prostaglandin and medroxyprogesterone acetate and to Rosemary Rollins and D. J. Bolt of the Reproduction Laboratory for conducting the blood serum progesterone assays. regardless of whether the estrous cycle was prolonged or normal in length.

Reduction of sperm transport in ewes by superovulation treatments

“…However, considerably larger numbers of spermatozoa were attached to ova recovered on Day 1 from surgically inseminated than from vaginally inseminated ewes (data not shown). (Hawk & Conley, 1975 ;Hawk & Cooper, 1977). The less-pronounced reduction in numbers in ewes synchronized with progestagen sponges was not significant, although other workers using larger numbers of animals have demonstrated an impairment of sperm transport due to this treatment (Quinlivan & Robinson, 1969;Allison & Robinson, 1970;Hawk & Conley, 1975).…”

“…The decreased fertility resulting from progestagen and PG treatment in the absence of superovulation has been attributed to decreased transport of spermatozoa through the cervix, on the basis of direct measurements of the numbers of spermatozoa in various portions of the reproductive tract (Quinlivan & Robinson, 1969;Allison & Robinson, 1970;Hawk & Conley, 1975;Hawk & Cooper, 1977). The present experiments were undertaken to compare the extent to which these oestrus-synchronizing agents, alone and in combination with two gonadotrophin preparations, PMSG and (Armstrong & Evans, 1984).…”

Synchronisation of oestrus and fertility in sheep treated with progestagen-impregnated implants, and prostaglandins with or without intravaginal sponges and subcutaneous pregnant mare's serum

“…comm.). Hawk (1973) and Hawk & Cooper (1977) have established that the transport of spermatozoa within the genital tract of the ewe is impaired in prostaglandin-treated ewes in much the same way as in progestagen-treated ewes. This almost certainly results in a reduced fertilisation rate M. P. Boland, unpubl.)…”

Synchronization of œstrus in ewes with Provera sponges/PMSG, prostaglandin F2α or the prostaglandin analogue, ICI 80996, and fertility following natural mating or artificial insemination

“…). Indeed, evidence has accumulated suggesting poor sperm transport and survival within the female reproductive tract after progestagen treatment Robinson, 1973 ;Hawk and Cooper, 1977).…”