Combining two injectable progesterone formulas for estrous synchronization in ewes.

The study aimed to evaluate the effectiveness of combining two injectable progesterone (iP4) formulas for estrous synchronization in ewes and to compare it with traditional intravaginal progesterone devices. Additionally, the study assessed whether the inclusion of GnRH enhances the reproductive outcomes of the iP4 treatment. Two experiments were conducted.

The pFSH dose affects the efficiency of in vivo embryo production in Santa Inês ewes.

This study compared the follicular growth, superovulatory response, and in vivo embryo production after administering two doses of porcine follicle-stimulating hormone (pFSH) in Santa Inês ewes. The estrous cycle of 36 multiparous ewes was synchronized with the Day 0 protocol and superovulated with 133 mg (G133, n=18) or 200 mg (G200, n=18) of pFSH. Ultrasonographic evaluations of the ovaries were performed, ewes were mated and submitted to non-surgical embryo recovery.

Reproductive seasonality of hair rams under tropical conditions: an alternative for non-seasonal lamb production?

Reproductive seasonality limits the periods of breeding on the year and, therefore, productive output. However, some breeds appear as probably non-seasonal. The aim of the study was to characterize the seasonal pattern of Santa Inês rams, including an ultrasound characterization of the reproductive tract, testosterone concentrations, and semen characteristics.

Progestogen supplementation during superovulation leads to higher embryo viability and TGFB1 gene expression in sheep.

This study aimed to compare the effect of the administration of either medroxyprogesterone acetate (MPA) or progesterone (P4) in superovulation (SOV) treatments applied during the first follicular wave on follicular development, embryo yield, and the expression of genes related to pluripotency maintenance, differentiation of the trophectoderm, cell growth and differentiation, apoptosis and energy metabolism in sheep embryos. The estrous cycle of 36 multiparous ewes was synchronized with a short protocol, and the animals were randomly allocated to three groups. At the beginning of SOV, 12 ewes per treatment received an intravaginal sponge impregnated with 60 mg of MPA (TMPA), or an intravaginal device containing 0.

Hormonal protocol used for cervical dilation in ewes does not affect morphological embryo quality but reduces recovery rate and temporarily alters gene expression.

Background: Information on the impact of hormonal protocols for cervical dilation on the quality of ovine embryos is scarce.

Methods: To compare the quality of embryos after cervical dilation protocol, ewes (n = 64) were allocated into either a treated group (100 μg estradiol benzoate intravenous and 0.12 mg cloprostenol intramuscularly, 12 hours before embryo collection plus 100 iu oxytocin intravenous 15 minutes before the collection procedure) or a control group (saline).

Performance, biochemical and physiological parameters of Dorper × Santa Ines lambs fed with three levels of metabolizable energy.

This study aimed to evaluate the performance and the blood biochemical and physiological parameters of Dorper × Santa Ines lambs receiving three levels of metabolizable energy (ME). A completely randomized design with three treatments (ME levels) and eight replicates (lambs) was used. Twenty-four non-castrated male lambs of four months of age and 21.

Use of oxytocin to attain cervical dilation for transcervical embryo transfer in sheep.

The aim of this work was to determine whether a cervical dilation protocol (CDP) composed of only oxytocin can be used to perform transcervical (non-surgical) embryo transfer in sheep (NSET) without affecting the viability of the corpus luteum (CL). Likewise, we evaluated whether a cervical transposing test with a Hegar dilator (CT Hegar test), performed at oestrous time, could be used to screen ewes for NSET (greater or lower chances to transpose the cervix). For that, oestrous and ovulation synchronization was performed in 25 Santa Inês ewes to induce the dioestrous condition.

Transcervical vs. laparotomy embryo collection in ewes: The effectiveness and welfare implications of each technique.

This study assessed animal welfare in ewes subjected to transcervical (TC) or laparotomy (LP) embryo collection, and the efficiency of these two techniques. Santa Inês ewes (n = 57) received a protocol for estrus synchronization and superovulation. Cervical dilation protocol was initiated 12 h before embryo collection in all ewes.

Cervical transposition test using Hegar dilator at oestrus as a tool to select ewes for transcervical embryo collection.

This study evaluated the cervical transposition method as a tool to select ewes for embryo collection by transcervical route. Adult Santa Inês ewes (n = 50) received Day 0 protocol for superovulation treatments. The cervix transposition test was performed both at oestrus and at the embryo collection time.

Dose and administration protocol for FSH used for ovarian stimulation affect gene expression in sheep cumulus-oocyte complexes.

The present study evaluated the effect of four ovarian stimulation protocols on the follicular population and molecular status of cumulus-oocyte complexes (COCs). Twelve Santa Inês ewes (in a cross-over design) received 80 or 120mg FSH alone in a multiple-dose (MD80 and MD120) regimen or in combination with 300IU equine chorionic gonadotrophin (eCG) in a one-shot (OS80 and OS120) protocol. The follicular population, COC recovery rate, mean COCs per ewe and the rate of brilliant Cresyl blue-positive (BCB+) COCs were similar among treatments (P>0.

Anti-Müllerian hormone and antral follicle count are more effective for selecting ewes with good potential for in vivo embryo production than the presence of FecG mutation or eCG pre-selection tests.

This study aims to compare four different methods for selecting high responding sheep donors for in vivo embryo production. These methods include a pre-selection eCG test (eCG), antral follicle count (AFC), plasma anti-Müllerian hormone measurement (AMH) and genotyping for the presence of the FecG mutation (a polymorphism in the GDF9 gene associated with increased ovulation rate). Santa Ines ewe lambs (n = 25) underwent superovulation (SOV) with 800 IU equine chorionic gonadotropin (eCG) and the corpus luteum (CL) count was recorded by laparoscopy after eight days.

Use of two doses of cloprostenol in different intervals for estrus synchronization in hair sheep under tropical conditions.

This study evaluated the effect of two doses of prostaglandin at different intervals on reproductive parameters of crossbred ewes. In Experiment 1, 30 ewes received two doses of 120 μg cloprostenol at 7 (G ), 9 (G ), or 11.5 (G ) days apart.

Early pregnancy diagnosis in ewes by subjective assessment of luteal vascularisation using colour Doppler ultrasonography.

This study was designed to evaluate early pregnancy diagnosis using colour Doppler ultrasonography (US) for luteal vascularisation assessment. In Study 1, 28 ewes were artificially inseminated (Day 0), and luteal vascularisation was assessed from Day 12 to Day 19 by two evaluators using colour Doppler US, categorising the corpus luteum (CL) on a subjective scale ranging from 1 to 4. Females bearing a CL with score 2 or greater were presumably considered pregnant.

l-carnitine supplementation during vitrification or warming of in vivo-produced ovine embryos does not affect embryonic survival rates, but alters CrAT and PRDX1 expression.

l-carnitine is an antioxidant and β-oxidation stimulator substance commonly used to improve metabolic performance of oocytes and embryos in in vitro systems. However, few studies have evaluated its beneficial effects in embryos produced in vivo. This study aimed to evaluate the effect of l-carnitine supplementation into vitrification or warming solutions on the post-warming character of day 6-7 in vivo-produced ovine embryos.

Effect of different hormonal combinations on follicular wave emergence and superovulatory response in sheep.

The aim of the present study was to compare hormonal treatments to induce and synchronize follicular wave emergence to improve the results of superovulatory (SOV) treatments in ewes. In Experiment 1 (n = 66), ewes were treated with a progesterone intravaginal implant plus a PGF analogue (group G), or with the same treatment plus estradiol benzoate (G), a GnRH agonist (G), or both, estradiol benzoate and a GnRH agonist (G) in a 2 × 2 factorial arrangement. Follicular wave emergence was determined by ultrasound.