Güven KAŞIKÇI, Ümüt CİRİT, Mehmet Can GÜNDÜZ, Süleyman BACINOĞLU, Ahmet SABUNCU

Effects of halving intravaginal sponges and eCG dose on estrus response and fertility in Tahirova ewes during the breeding season

The aim of this study was to compare the effect of halving the intravaginal sponges impregnated with 20 mg of flugestone acetate (FGA; 20 or 10 mg) and a dose of equine chorionic gonadotropin (eCG; 600 or 300 IU) on fertility in Tahirova ewes. A total of 200 Tahirova ewes were randomly assigned to 1 of 2 groups during the breeding season. Half of the ewes (n = 100) were treated with whole intravaginal sponges (WS, 20 mg of FGA) and the other half (n = 100) with halved sponges (HS, 20 mg of FGA) for 14 days. The ewes in both groups were further randomly divided into 2 subgroups (of 50 ewes each). Half of the ewes in each group received a 600 IU dose and the other half received a 300 IU dose of eCG at sponge withdrawal via IM route. As a result, 4 treatment groups, WS 600, WS 300, HS 600, and HS 300 were established. All the ewes were injected with PGF2a (0.294 mg, IM) a day prior to sponge withdrawal. Blood samples were collected from 40 randomly selected ewes (20 from the WS group and 20 from the HS group) on the 1st, 4th, 7th, 10th, and 13th day after sponge insertion. Serum progesterone profiles of ewes treated with whole and halved FGA sponges were similar on all sampling days. The FGA dose (whole or halved sponge) affected the pregnancy rate and the dose of eCG (600 or 300 IU) affected the fecundity significantly, while it did not affect the pregnancy rate. The data also demonstrate that FGA dose × eCG dose interaction affects estrus and lambing rates significantly. In the whole sponge groups, ewes treated with 600 IU of eCG had significantly lower lambing rates, but a significantly higher fecundity rate compared to the ewes injected with 300 IU of eCG. While the fecundity rates were similar in the 600 IU eCG groups (WS600 and HS600), estrus, pregnancy, and lambing rates were significantly higher in the HS600 group compared to the WS600 group. It was concluded from the study that the sponges containing 20 mg of FGA can be halved for a more economical estrus synchronization at the farm level in Tahirova ewes, resulting in higher pregnancy rates, but halving the recommended dose of eCG (600 IU) could decrease the fecundity rate.

Anahtar Kelimeler:

Key words: Tahirova ewes, synchronization, halved sponge, eCG, progesterone

Effects of halving intravaginal sponges and eCG dose on estrus response and fertility in Tahirova ewes during the breeding season

Keywords:

Key words: Tahirova ewes, synchronization, halved sponge, eCG, progesterone,

PDF

___

Yalçin, B.C.: Sheep and goats in Turkey. FAO animal production and protection paper, 60, Rome. 1986, 31-72.
Ali, Eff ect of time of eCG administration on follicular A.: response and reproductive performance of FGA-treated Ossimi ewes. Small Rumin. Res., 2007; 72: 33-37.
Langford, G.A., Marcus, G.J., Batra, T.R.: Seasonal eff ects of PMSG and number of inseminations on fertility of progestagen treated sheep. J. Anim. Sci., 1983; 57: 307-312.
Driancourt, M.A.: Ovarian feature contributing to the variability of PMSG-induced ovulation rate in sheep. J. Reprod. Fertil., 1987; 80: 207-212.
Odde, K.G.: A review of synchronization of estrus in postpartum cattle. J. Anim. Sci., 1990; 68: 817-827.
Greyling, J.P.C., Erasmus, J.A., Taylor, G.J., Van der Merwe, S.: Synchronization of estrus in sheep using progestagen and inseminating with chilled semen during the breeding season. Small Rumin. Res., 1997; 26: 137-143.
Ungerfeld, R., Rubianes, E.: Short term primings with diff erent progestogen intravaginal devices (MAP, FGA and CIDR) for eCG-estrous induction in anestrus ewes. Small Rumin. Res., 2002; 46: 63-66.
Simonetti, L., Blanco, M.R., Gardón, J.C.: Estrus synchronization in ewes treated with sponges impregnated with diff erent doses of medroxyprogesterone acetate. Small Rumin. Res., 2000; 38: 243-247.
Robinson, T.J., Quinlivan, T.D., Baxter, C.: Th e relationship between dose of progestagen and method of preparation of intravaginal sponges on their eff ectiveness for the control of ovulation in the ewe. J. Reprod. Fertil., 1968; 17: 471-483.
Stock, A.E., Fortune, J.E.: Ovarian follicular dominance in cattle: relationship between prolonged growth of the ovulatory follicle and endocrine parameters. Endocrinology, 1993; 132: 1108-1114
Hatler, T.B., Hayes, S.H., Ray, D.L., Reames, P.S., Silvia, W.J.: Eff ect of subluteal concentrations of progesterone on luteinizing hormone and ovulation in lactating dairy cows. Vet. J., 2008; 177: 360-368.
Romano, J.E., Rodas, E., Ferreira, A., Lago, I., Benech, A.: Eff ects of progestagen, PMSG and artifi cial insemination time on fertility and prolifi cacy in Corriedale ewes. Small Rumin. Res., 1996; 23: 157-162.
Eppleston, J., Roberts, E.M.: Th e eff ects of progestagen, PMSG and time of insemination on fertility in ewes following intrauterine insemination with frozen semen. Aust. Vet. J., 1986; 63: 124-125.