The effects of time and dose of pregnant mare serum gonadotropin (PMSG) on reproductive efficiency in hair sheep ewes

Abstract

The aim of this study was to evaluate the effects of dose and application time of pregnant mare serum gonadotropin (PMSG) on reproductive performance of hair sheep ewes synchronized with fluorogesterone acetate (FGA) under tropical conditions of Northeastern Mexico. Ninety-nine hair ewes (63 Blackbelly and 36 Pelibuey) were treated with intravaginal sponges during 10 days. After insertion of FGA sponges, ewes were divided into four groups, and PMSG was injected intramuscularly at doses of 100, 200, and 400 IU. Relative to FGA sponge removal, PMSG was administrated at -48 h, -24 h, and at sponge removal. PMSG was not administered to the control group. Control ewes had similar (P > 0.05) lambing rate, fertility, and fecundity than those treated with 100 IU of PMSG, but lower (P < 0.05) percentages to these variables than those treated with 200 and 400 IU of PMSG. Time to estrus decreased linearly, and ovulation rate increased quadratically as PMSG dose increased (0 to 400 IU). Administration of PMSG before sponge removal increased (P < 0.01) response to estrus and decreased (P < 0.01) interval to estrus compared with control. Ovulation rate, lambing rate, fertility, and fecundity were not affected (P > 0.05) by administration time of PMSG. Both dose and time of PMSG application did not affect (P > 0.05) pregnancy rate, percentage of single and multiple lambing, and prolificacy. In conclusion, results show that the dose of 400 IU of PMSG administered before sponge withdrawal in an estrus synchronization protocol improved reproductive efficiency of hair sheep ewes.

Reproductive efficiency of Pelibuey and Romanov × Pelibuey ewes synchronized with synthetic progesterone and low doses of PMSG under a hot environment

“…On the other hand, fecundity was by 44% higher in ewes treated with 280 UI of PMSG, which is due to the numerical difference in single lambing observed in ewes treated with 140 IU, and to the presence of ewes that lambed 3 or 4 offsprings in the group treated with 280 IU. Under thermoneutral conditions, Quintero-Elisea et al (2011) found also higher fecundity percentage in Pelibuey and Blackbelly ewes treated with 200 IU of PMSG than in those treated with 100 IU. In general, these results suggest that low PMSG doses as 280 IU can be used in combination with FGA impregnated sponges to improve the lamb production in Pelibuey and Pelibuey × Romanov ewes during the season of high environmental temperatures.…”

“…In hair and wool sheep, vaginal insertion of fluorogestone acetate (FGA) impregnated sponges for 10-12 days in combination with the administration of 400-500 IU of pregnant mare serum gonadotropin (PMSG) prior to or at time of sponge removal have been the synchronization and/or induction protocol more used worldwide, with acceptable results on response to estrus, fertility, and prolificacy (Barret et al, 2004;Avendaño-Reyes et al, 2007;Quintero-Elisea et al, 2011;Kermani et al, 2012). However, the protocol brings about elevated costs due to the high PMSG dose used, therefore economically this management strategy is little profitable for sheep producers.…”

Co-expression analysis and identification of fecundity-related long non-coding RNAs in sheep ovaries

“…All the experimental ewes were treated with fluorogestone acetate vaginal sponges (40 mg; Chronogest, Intervet, Federal District, México) for 10 days. Then, the sheep were intramuscularly injected with pregnant mare’s serum gonadotropin (Ningbo Hormone Co., Ningbo, China) at a dose of 400 IU for synchronized oestrus41. All ewes were euthanized between 24 and 36 h after having reached spontaneous oestrus after one cycle.…”

Ovarian proteomic study reveals the possible molecular mechanism for hyperprolificacy of Small Tail Han sheep

“…Then sponges were removed and pregnant mare serum gonadotropin (Ningbo Hormone Co., Ningbo, China) was injected i.m. at a dose of 400 IU into each sheep to synchronize estrus43. Twenty-four hours after spontaneous estrus was detected, all ewes were euthanized.…”