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.

Social Stress during the Estrus or Luteal Phase in Sheep.

In mammals, progesterone and estrogens affect the stress response. The study aimed to compare the physiological and behavioral responses to the social isolation of ewes during the estrus or luteal phase. Estrous and diestrous ewes (n = 10 and 8 respectively) were individually isolated in a novel place for 10 min.

Semen collection and ejaculation trigger changes in the blood flow of the reproductive system in rams.

The aim of this study was to determine if ejaculation modifies the testicular and accessory sex glands' blood flow after ejaculation, and if those changes differ according to the process that leads to ejaculation. Twelve adult Corriedale rams were used and assigned at random to the four procedures that lead to ejaculation: (G1) electroejaculation; (G2) artificial vagina; (G3) transrectal ultrasound-guided massage of the accessory sex glands; (G4) natural mating. Hemodynamic characteristics evaluation of the male reproductive system was conducted immediately before and at 30 and 90 min after ejaculation.

Luteal Function, Biometrics, and Echotextural Attributes in Santa Inês Ewes Superovulated with Different Total Doses of Porcine Follicle-Stimulating Hormone.

Premature regression of corpora lutea (PRCL) may adversely affect the outcome of hormonal ovarian superstimulation in small ruminants, and the total dose of exogenous gonadotropins used may be one of the causes of this condition. There were two major objectives of the present study: (1) to evaluate the effects of different superovulatory doses of porcine follicle-stimulating hormone (pFSH) on the biometry, blood perfusion (Doppler), and echotextural characteristics of luteal structures; and, (2) to determine the usefulness of biometric, vascular, and echotextural luteal variables, as well as measurements of circulating progesterone (P) concentrations for early detection of PRCL in superovulated Santa Inês ewes. Twenty-seven Santa Inês ewes received an intravaginal P-releasing device (CIDR) from Days 0 to 8 (Day 0 = random day of the anovulatory period).

Doppler sonography of the umbilical and uterine arteries blood flow of pregnant Saanen goats.

The objective was to evaluate the blood flow of the uterine artery (UA) and umbilical artery (UMB) in the physiological pregnancy of goats by means of Doppler throughout the gestational period. Twenty-five Saanen goats weighing 55 ± 10 kg and aged between 2 and 5 were evaluated weekly, from the 21 until the 143 day of gestation, and daily from that period until parturition. Values for peak systolic velocity (PSV), end diastolic velocity (EDV) and resistance (RI) and pulsatility (PI) indices of the uterine and umbilical arteries were determined.

Multiple matings modify the estrous length, the moment of ovulation, and the estradiol and LH patterns in ewes.

In several species, mating reduces the estrous length and advances ovulation. The aim of this study was to determine if multiple matings reduces the estrous length and modifies the moment of ovulation, as well as the estradiol and LH patterns in ewes. The estrous cycle of Corriedale ewes was synchronized, and the onset of receptivity was monitored every 3 h with rams, avoiding mating.

Assessment of dopperfluxometric indices of maternal-fetal structures in pregnant ewes.

The aim of this study was to evaluate the blood flow of the uterine artery, fetal aorta and umbilical artery in the physiological pregnancy of sheep by means of pulsed Doppler throughout the gestational period. Thirty Santa Inês ewes weighing between 45.4±4.

Using transrectal ultrasound-guided massage of the accessory sex glands for buck semen collection yields semen with greater cryoresistance than electroejaculation alone during the breeding season.

The cryoresistance of bucks' semen collected by transrectal ultrasound-guided massage of the accessory sex glands (TUMASG) and electroejaculation (EE) was compared during the breeding season (Study 1) or the late non-breeding season (Study 2). Semen was collected from 10 Gabon bucks with both methods in each season and then frozen according to a standardized protocol. The time required for ejaculation, the number of electrical pulses applied, the sum of the electrical pulses applied∗voltage and the total number of vocalizations emitted during the collection by each animal were recorded.

Maternal and fetal ultrasonographic characteristics, vulvar temperature, and vaginal mucous impedance as variables associated with the onset of parturition in term and induced pre-term ewes.

The aim of this study was to assess and compare ultrasonographic characteristics of maternal and fetal structures, vulvar temperatures, and vaginal mucous impedance in pregnant ewes in the term parturition group (TPG, n = 15) and induced pre-term parturition group (IPPG; n = 15). All the measurements were taken every 12 h throughout the last gestational week. Maternal and fetal structures and the fetal heart rate (HR) were assessed using ultrasonography.

Reproductive response of postpartum spring-lambing ewes: effects of weaning on follicular growth and postpartum interval on response to ram placement with ewes ("ram effect").

The aim of the first experiment was to determine if follicular growth rate in ewes increases spontaneously or after gonadotropin administration after lamb weaning during the period of seasonal anestrus. To conduct this experiment, there were postpartum lactating ewes from which lambs were or were not weaned when 68 to 72 days old (Day 0). The ovaries were assessed using ultrasonography from Day 0 to 9, followed by the administration of 200 IU of eCG on Day 7 to all ewes to determine capacity of follicles to respond to gonadotropin stimulation.

Follicular dynamics and in vivo embryo production in Santa Inês ewes treated with smaller doses of pFSH.

To evaluate follicular dynamics, there was assessment of superovulatory response and in vivo embryo production in ewes treated with relatively smaller doses of exogenous pFSH than typically used in combination with a dose of eCG at the beginning of the gonadotropin treatment period. Santa Inês ewes (n = 24) were randomly divided into three groups, based on mg dose of pFSH administered: G200 (n = 8), G133 (n = 8) and G100 (n = 8) in eight decreasing doses at 12 -h intervals. All ewes were treated with 300 IU of eCG concomitantly starting with first pFSH administration.

Early luteal development in Santa Inês ewes superovulated with reduced doses of porcine follicle-stimulating hormone.

The aim was to compare the early luteal development in ewes superovulated with different doses of pFSH. Twenty-nine Santa Inês ewes received a progesterone device (CIDR®) for 8 days. Gonadotrophic treatment started on Day 6: G200 (control, n = 9, 200 mg); G133 (n = 10, 133 mg); and G100 (n = 10, 100 mg of pFSH).

B-mode ultrasonography and ecobiometric parameters for assessment of embryonic and fetal development in sheep.

The aim in this study was to evaluate the maternal-fetal development during physiological gestation in sheep by means of ultrasonography and to predict the gestational age by mathematical formulae. Thirty Santa Inês sheep were included. Evaluations were performed weekly from the 3rd to 21st gestational week.