Short oestrus synchronization with PGF2alfa, estradiol and GnRH or hCG in lactating dairy cows

• Autorzy: Cirit U. , Tas M. , Bacinoglu S. , Ozdas O.B. , Ak K. , Ileri I.K.
• Języki publikacji: EN

Abstrakty

EN

The objectives of this study were to develop short oestrus synchronization methods allowing timed artificial insemination (TAI) in lactating dairy cows and to compare the synchronizing effects of the use of human chorionic gonadotropin (hCG), instead of a gonadotropin releasing hormone (GnRH), on ovulation and pregnancy rates. An additional goal was to determine the effects of the presence or absence of an active corpus luteum (CL) on the treatment efficacy at the beginning of treatment. Sixty-three cows at random stages of the oestrus cycle on the 50th-95th postpartum day were randomly distributed into two groups. Cows of GnRH group (n = 33) received prostaglandin F-two alpha (PGF, 0.150 mg), estradiol propionate (EP, 2 mg) and GnRH (50 µg) in 24 hour intervals (PGF at hour 0; EP at hour 24 and GnRH at hour 48). Cows in the hCG group (n = 30) were treated in a similar manner to the GnRH group, but, alternately, these cows received hCG (500 IU, i.m.) instead of GnRH. All cows in the treatment group were inseminated timely 16-20 hours after GnRH or hCG injections regardless of oestrus signs. During the study, animals exhibiting natural oestrus were inseminated 10-12 hours later and served as controls (n = 44). Cows in the hCG group have significantly higher synchronized (P = 0.018) and total (P < 0.05) ovulation rates and shorter intervals between the last hormone injection and ovulation (P = 0.012) compared to cows in the GnRH group. In both GnRH and hCG groups, cows with an active CL at the beginning of the treatment have acceptable pregnancy rates (40.0% and 47.6% respectively, P > 0.05). The PGF/EP/GnRH and PGF/EP/hCG treatments resulted in comparable pregnancy rates after TAI of lactating dairy cows at random stages of the oestrus cycle relating to those inseminated at natural oestrus (33.3%, 40.0% and 40.9% respectively, P > 0.05).

• Wydawca: -
• Czasopismo: Medycyna Weterynaryjna
• Rocznik: 2008
• Tom: 64
• Numer: 02
• Opis fizyczny: p.164-167,ref.

Twórcy

autor

Cirit U.

• Department of Reproduction and Artificial Insemination, Faculty of Veterinary Medicine, Istanbul University, 34320 Avcilar, Istanbul, Turkey

autor

Tas M.

autor

Bacinoglu S.

autor

Ozdas O.B.

autor

Ak K.

autor

Ileri I.K.

Bibliografia

• 1. Cirit Ü., Ak K., İleri İ. K.: New strategies to improve the efficiency of the ovsynch protocol in primiparous dairy cows. Bull. Vet. Inst. Pulawy 2007, 51, 47-51.
• 2. Cirit Ü., Bacinoglu S., Taş M., Demir K., Ak K., İleri İ. K.: The investigation of short estrus synchronization methods in Holstein cows. 5th Joint Scientific Symposium of the Veterinary Faculties of Ludwig-Maximilians Universität München and Istanbul University, Istanbul 2006, October 05-06, p. 77.
• 3. De Rensis F., Peters A. R.: The control of follicular dynamics by PGF2α, GnRH, hCG and oestrus synchronization in cattle. Reprod. Dom. Anim. 1999, 34, 49-59.
• 4. Folman Y., Kaim M., Herz Z., Rosemberg M.: Comparison of methods for synchronization of estrous cycles in dairy cows. II. Effects of progesterone and parity on conception. J. Dairy Sci. 1990, 73, 2817-2825.
• 5. López-Gatius F.: Effects of cloprostenol, human chorionic gonadotropin and estradiol benzoate treatment on estrus synchronization in dairy cows. Theriogenology 1989, 32, 185-195.
• 6. López-Gatius F.: Reproductive performance of lactating dairy cows treated with cloprostenol, hCG and estradiol benzoate for synchronization of estrus followed by timed AI. Theriogenology 2000, 54, 551-558.
• 7. López-Gatius F., Vega-Prieto B.: Pregnancy rate of dairy cows following synchronization of estrus with cloprostenol, hCG and estradiol benzoate. J. Vet. Med. A. 1990, 37, 452-454.
• 8. Moreira F., Orlandi C., Risco C. A., Mattos R., Lopes F., Thatcher W. W.: Effects of pre-synchronization and bovine somatotropin on pregnancy rates to a timed artificial insemination protocol in lactating dairy cows. J. Dairy Sci. 2001, 84, 1646-1659.
• 9. Murugavel K., Yániz J. L., Santolaria P., López-Béjar M., López-Gatius F.: Luteal activity at the onset of a timed insemination protocol affects reproductive outcome in early postpartum dairy cows. Theriogenology 2003, 60, 583-593.
• 10. Plaizier J. C. B., King G. J., Dekkers J. C. M., Lissemore K.: Estimation of economic values of indices for reproductive performance in dairy herds using computer simulation. J. Dairy Sci. 1997, 80, 2775-2783.
• 11. Rounsaville T. R., Oltenacu P. A., Milligan R. A., Foote R. H.: Effects of heat detection, conception rate, and culling policy on reproductive performance in dairy herds. J. Dairy Sci. 1979, 62, 1435-1442.
• 12. Schmitt E. J. P., Barros C. M., Fields M. J., Diaz T., Kluge J. M., Thatcher W. W.: A cellular and endocrine characterization of the original and induced corpus luteum after administration of a gonadotropin-releasing hormone agonist or human chorionic gonadotropin on day five of the estrous cycle. J. Anim. Sci. 1996, 74, 1915-1929.
• 13. Starbuck M. J., Dailey R. A., Inskeep E. K.: Factors affecting retention of early pregnancy in dairy cattle. Anim. Reprod. Sci. 2004, 84, 27-39.

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