Efficacy of Various Synchronization Protocols on the Estrus Behavior, Lambing Rate and Prolificacy in Rahmani Egyptian Ewes During the Non-Breeding Season

Comparative evaluation of estrus synchronization protocols on reproductive performance and estrus behavior in Barbados Black Belly sheep

Background and Aim

Estrus synchronization of ewes has been accomplished using several protocols with various degrees of success in improving reproductive efficiency and obtaining the most effective protocol used in sheep farming. This study aimed to compare the effectiveness of three treatment protocols and to record the intensity and duration of estrus signs and pregnancy rate in Barbados Black Belly (BBB) sheep.

Materials and Methods

Thirty-two primipara BBB ewes aged 18-24 months were equally divided into three treatment groups. T1: the ewes were injected intramuscularly with 2 mL Lutalyse (PGF2α) (10 mg) on days 0 and 10. T2: 1 mL Fertiline (50 μg; Gonadorelin acetate) on day 0 and 2 mL lutalyse (10 mg) on day 7. T3: 1 mL fertiline (50 μg) on day 0, 2 mL lutalyse (10 mg) on day 7, and 1 mL Fertiline (50 μg) on day 9. Estrus response was assessed using naturally mating rams and ewes. Pregnancy was determined using ultrasonography between 55 and 80 days after the last hormonal injection. The following estrus signs were noted: Swollen vulva, mucus discharge, sniffing, excitement, loss of appetite, mounting, and rapid tail movement.

Results

Of the expressed signs, swollen vulva was most frequent, whereas loss of appetite and mucus discharge were the least overt signs recorded. The estrus response (%), onset (%), and duration (h) in ewe synchronization of the three treatment protocols were 100%, 58.3 ± 23.4%, and 48.0 ± 18.2 h (T1), 100%, 61.7 ± 41.2%, and 45.0 ± 27.0 h (T2), and 37.5%, 32.1 ± 1.7%, and 29.2 ± 1.25 h (T3), respectively. The pregnancy rates were 87.5%, 87.5%, 37.5%, and 50.0% in T1, T2, T3, and T4, respectively.

Conclusion

Prostaglandin F2α+PGF2α and GnRH+PGF2α synchronization protocols were more effective in the fertilization of BBB ewes with better expression of estrus signs compared with the GnRH+PGF2α+GnRH (OVS) protocol.

The effect of progesterone injection combined with prostaglandineF2α, GnRH and hCG administrations on the pregnancy and lambing rate of lactating and non-lactating fat-tailed ewes during the breeding season

The objective was to compare the effect of human chorionic gonadotropin (hCG) and gonadotropin-releasing hormone (GnRH) on the pregnancy and lambing rate of treated ewes with a short-term progesterone (P4) injection during the breeding season. In Exp 1, non-lactating ewes (n = 158) were used and received P₄ , three times every 48 h and received PGF_2α along with the last dose of P4. Ewe received hCG (n = 79, 3PHCG, IM) or GnRH (n = 79, 3PGnRH, IM) 24 h after the last dose of P4 treatment. In the Exp 2, lactating ewes (n = 62) received P4 and hCG (n = 24, 3PHCG) or GnRH (n = 24, 3PGnRH) similar to Exp 1, or considered as control (n = 14) and received PGF2α 48 h before ram release. Rams were released into the studied ewe's flock 24 h after the hCG or GnRH administration, and pregnancy diagnosis was performed on day 50 after ram release. In Exp 1, all reproductive indices were not significant between groups except twin lambing rate, that was higher in the 3PHCG (11.3%) compared with the 3PGnRH (1.9%) group (p = .05). There were no significant differences in overall pregnancy and lambing rates between 3PHCG (70.9% and 67.1%) and 3PGnRH (69.6% and 68.4%) groups (p > .05). In Exp 2, all reproductive parameters were not significant between 3PHCG and 3PGnRH groups (p > .05). There was significant difference in overall oestrous rate between control (35.7%) and treatment (3PHCG, 70.9% and 3PGnRH, 79.2%) groups. To conclude, administration of GnRH can be a good alternative to hCG injection under field conditions.

Treatments with intravaginal sponges for estrous synchronization in ewes: length of the treatment, amount of medroxyprogesterone, and administration of a long-acting progesterone

We evaluated if alternative treatments achieve at least similar results as traditional long treatments with intravaginal sponges (IVS) in three experiments considering (1) the use of 6-day treatments associated or not with the administration of PGF2alpha at IVS insertion; (2) a reduction of 50% MAP content in short-term or traditional treatments, with or without change of the IVS 6 days after its insertion; and (3) the substitution of IVS for long-time acting injected progesterone associated with the administration of a PGF2alpha. More ewes came into estrus with long than short IVS treatments, independently of the MAP IVS content. Fewer ewes came into estrus if the IVS containing 30 mg was replaced 6 days after its insertion. The length of the treatment did not affect the conception rate, but the pregnancy rate was greater in 12 than 6 days treatments. The administration of long-acting progesterone did not prevent the lower conception rate associated with the use of PGF2alpha and was less effective to synchronize estrus, but the conception rate did not differ from that of 12d IVS treatments. Overall, MAP content could be decreased without affecting the estrous rate; thereafter, the MAP IVS content should be decreased in the commercial devices. Although pregnancy rate was lower using long-acting injected progesterone than with IVS, as the conception rate did not differ, it is interesting to study deeper the use of this treatment, especially if preparations of progesterone with a longer half-life are developed. However considering all the results, the traditional long IVS treatment still provided the best result.

Effect of Simmental bull seminal plasma protein in egg yolk-citrate extender on Kacang buck semen fertility

The genetic resources of Indonesia's indigenous Kacang goat require preservation. Artificial insemination is expected to accelerate population increases and preserve genetic resources simultaneously. The present study was the maiden attempt for cryopreservation of Kacang buck sperm. The objectives of this study were to determine whether the supplementation of superior Simmental bull seminal plasma protein in egg yolk-citrate extender could improve the quality of post-thawed Kacang buck sperm, increase conceptions rates, and improve kidding rates. Buck semen was diluted without supplementation (T0) and with supplementation of 2.5 mg (T1) and 5 mg (T2) of Simmental bull seminal plasma protein per mL egg yolk-citrate extender. Extended semen was packed in 0.25 mL straw as cryopreserved frozen semen. Post-thawed semen samples were evaluated for viability, motility, intact plasma membranes, malondialdehyde level, and DNA fragmentation. Estrus was synchronized for sixty Kacang does, which were divided randomly into three groups and inseminated using post-thawed semen. The progesterone serum concentration of the does was measured 7 and 22 days post-insemination to detect ovulation and conception. Pregnancy was confirmed using abdominal palpation at 43 days post-insemination and by observing birth. The T1 group showed the highest (P < 0.05) post-thawed viability, motility, and intact plasma membrane. Conception, pregnancy and kidding rates were also higher in T1 than other treatment groups. In conclusion, the 2.5 mg Simmental bull seminal plasma protein supplementation per mL egg yolk-citrate extender provided the best seminal quality and fertility of post-thawed Kacang buck semen.

The effect of medroxyprogesterone acetate with or without eCG on conception rate of fat-tail ewes in out of breeding season

Many protocols of estrous synchronization in ewes have been developed in the last few decades. The aim of this study was the effect of intravaginal progestogen, medroxyprogesterone acetate (MPA), sponges (a progesterone analogue) with or without equine chorionic gonadotropin (eCG) in out of breeding season of fat-tailed Iranian Shaal breed anestrus ewes to estimate the conception rate in suburb of Tehran-Iran. In total, 50 non-cyclic ewes out of 85 ewes with < 0.05 ng/ml progesterone (P4) and aged 2 to > 7 years old were selected for out of breeding season program in May-June 2018. They were distributed into two groups (control and treatment). The treatment group (no. 25) received 12 days a sponge containing 60 mg MPA and 500 IU eCG on the day of sponge removal. The control group (no. 25) received 12 days of sponge containing MPA only. Rams were introduced to the flock after removal of sponges in treatment group and concomitant in control group. They remained within the flock for 40 days. The ram to ewe ratio was 1 to 6. Transabdominal ultrasonography was performed for pregnancy diagnosis. The obtained data was analyzed using SPSS software version 16. The conception rate in treatment and control groups were differed significantly (P < 0.01). The conception rates in MPA and MPA+ eCG were 28% and 44%, respectively. Ewes (60%) with < 2 years old had the most conception rate. However, it was shown that use of vaginal sponges containing MPA and eCG in removal time of sponge can increase significantly the conception rate in out of breeding season fat-tail ewes Shaal breed.