Fertilization and embryonic survival in ewes synchronized with exogenous hormones during the anestrous and estrous seasons.

نویسندگان

  • D D Lunstra
  • R K Christenson
چکیده

Causes of reproductive loss in ewes synchronized and mated during the anestrous season and during the normal breeding season were compared with those for natural cyclic ewes mated in season. Synchronization of ewes in season and out of season with progestogen: pregnant mare serum gonadotropin (PMSG) increased ovulation rate, but the percentage of ewes ovulating did not differ from that noted for untreated ewes mated in season. However, synchronized ewes exhibited markedly higher total reproductive losses, both in season (49%) and out of season (58%), than did untreated ewes mated in season (25%). The two primary sources of the increased reproductive loss in synchronized ewes were increased fertilization failure and increased embryonic mortality, regardless of season. The increased fertilization failure was accompanied by a decrease in the number of accessory sperm per ovum and decreased tubal sperm numbers. The increased embryonic mortality among treated ewes was associated with increased variation in stage of embryo development within ewe and advanced stage of embryo development, which indicated that asynchronies of timing of onset of estrus, ovulation and fertilization may have occurred in synchronized ewes. The high reproductive losses for ewes treated out of season was characterized by a marked increase in fertilization failure, compared with that observed for ewes treated in season, in addition to the relatively high embryonic mortality associated with the synchronization treatment. Semen quality of rams was lower out of season than in season. It was concluded that the reduced and more variable lambing response often obtained for ewes treated with progestogen: PMSG during anestrus may be due to decreased semen quality of rams and increased asynchrony of events in the ewe reproductive tract.

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

منابع مشابه

Theriogenology Causes for Decreased Fertility in Out-of-season Mated Ewes

The interval from onset of estrus to preovulatory luteinizing hormone (LH) release, conception and fertilization rates, and number of accessory spermatozoa per ovum at 48 hr postmating in untreated cyclic ewes and fn progestogen-pregnant mare serum gonadotropin (PMSG) treated, anestrous ewes were compared in efforts to identify sources of lowered fertility for matings induced in anestrous ewes ...

متن کامل

Response of Breeds to Exogenous Hormones in Ewes

Three experiments were conducted, using 1,488 ewes during seasonal anestrous and during the normal estrous period, to evaluate the influence of breed on response to exogenous hormones. Treatment was intravaginal, progestogen pessaries Days 1 to 16, 10 mg crystalline progesterone on Day 16, followed by 750 IU PMS on Day 17. In the anestrous ewes a second PMS injection was given on Day 32 in one ...

متن کامل

Effects of FSH treatment in seasonally anestrous ewes on egg production, retrieval, and quality for use in in vitro fertilization procedures

Through the use of assisted reproductive technology (ART), we will be able to extend the use of genetically superior animals, and perhaps increase the number of offspring. These technologies include such procedures as estrus synchronization, superovulation, artificial insemination, embryo transfer, in vitro fertilization (IVF), and cloning. Because they exhibit seasonal breeding and multiple ov...

متن کامل

Effects of Organic and Inorganic Selenium Supplementation with Vitamin E during the Flushing Period on Reproductive Performance of Ghezel Ewes

Minerals and vitamins play an important role in animal nutrition with beneficial effects on animal reproductive performance. To investigate this issue, 44 Ghezel ewes weighing 55±  2 kg (Mean±SD) and 2-3 years old were randomly divided into groups (n=11), to investigate the effect of the selenium and vitamin E supplementation on blood hormones and metabolites and possible reproductive performan...

متن کامل

Anestrous Estrous Season Season Breeding Breeoing January June October Artificial Insemination / ~ Plasma L Assays Lambing

The influence of pregnant mares' serum gonadotropin (PMSG) on reproductive performance of sheep bred by artificial insemination (AI) was studied in the anestrous and estrous seasons. Ewes were treated with progestogenimpregnated intravaginal sponges in June and October. One-half of the ewes in each trial received PMSG at sponge removal and were inseminated 55 h after sponge removal. One-half of...

متن کامل

ذخیره در منابع من


  با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید

برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید

ثبت نام

اگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید

عنوان ژورنال:
  • Journal of animal science

دوره 53 2  شماره 

صفحات  -

تاریخ انتشار 1981