Luteal tissue characteristics of Morada Nova ewes with hCG application 7.5 days after the end of estrus synchronization protocol in the breeding season.

Results with the use of hCG after synchronization protocol are still inconsistent, which may vary according to breed, season, day of application and dose of the drug used. The aim of the present study was to evaluate the functionality of luteal tissue and ovarian perfusion after hCG treatment during early luteal phase. Estrus-synchronized ewes were randomly assigned to receive i.m. injection of 300 IU of hCG (G-hCG; n = 40) or 1 mL of saline (G-Control; n = 32) on Day 7.5 after progesterone withdrawal. Ultrasonographic evaluations of the ovaries and ovarian and iliac arteries were performed on Days 7.5, 10.5, 13.5, and 21.5. The accessory corpus luteum (aCL) formation rate was 52.5% for G-hCG. There was interaction (p > 0.05) for treatment (G-hCG and G-Control), days (7.5, 10.5, 13.5 and 21.5) and PD (Pregnant and Non-pregnant) for the variables of biometric characteristics of the corpus luteum B-Mode and Color Doppler on days 7.5, 10.5, 13.5 and 21.5. There was no difference (p > 0.05) for pregnancy rates and mean fetuses per ewe between the treatment groups. It is concluded that the application of hCG 7.5 days after the hormonal protocol in Morada Nova ewes in a breeding season is efficient in inducing aCL formation and increasing luteal tissue biometry. However, there was no effect on pregnancy rate.

Study of the factors affecting embryo yields and quality in superovulated Morada Nova ewes that underwent non-surgical uterine flushing.

The present study compared the outcomes of in vivo embryo production in Morada Nova ewes subjected to either 9-day (G-9SOV , n = 21) or 12-day (G-12SOV , n = 21) progesterone (P4 )-based estruses synchronization protocol coupled with superovulatory treatment with decreasing doses of porcine follicle-stimulating hormone (133 mg of pFSH given over 3 days). Non-surgical embryo recovery (NSER) was performed 6-7 days after the onset of oestrus. Total antral follicle count doubled from the first to the sixth pFSH dose in both groups (p < .05). Oestrus responses did not vary between the two groups of animals (95.2%). Corpora lutea (CL) were detected in 85.0% and 60.0% of ewes that previously manifested oestrus behaviour in G-9SOV and G-12SOV respectively. NSER was successfully completed in 86.2% of ewes that had CL (p > .05). The mean number of CL per ewe/successfully flushed donor ewe was greater (p < .05) in G-12SOV (12.3 ± 1.7/12.1 ± 1.9) than in G-9SOV (7.9 ± 1.4/8.2 ± 1.6). Mean numbers of retrieved blastocysts and viable embryos were greater (p > .05) in G-12SOV (5.8 ± 1.9 and 3.7 ± 1.7) than G-9SOV (3.5 ± 1.1 and 0.8 ± 0.3 respectively). The total follicle count (all follicles ≥2 mm in diameter) at the sixth pFSH dose (at P4 -device removal) was positively correlated (p < .05) with the number of CL (r = .95) and viable embryos (r = .91) in G-12SOV . The ewes with ≥10 Cl (48% of all flushed donors) yielded 80.5% of viable embryos. In summary: (a) Morada Nova ewes from G-12SOV group had better superovulatory responses compared with G-9SOV group; (b) total follicle count at the last pFSH dose was a good predictor of superovulatory responses only in the ewes primed with P4 for 12 days; and (c) animals with ≥10 ovulations are main contributors to viable embryo production in Morada Nova ewes.

Overnutrition of Ewe in Late Gestation and the Impact on Placental Efficiency and Lamb's Performance.

The objective of the study was to evaluate energy or energy/protein supplementation in the ewe diet, in the last third of gestation, on maternal placental and endocrine characteristics, as well as its effects on the behavior of neonatal lambs and productive performance until weaning. A total of 128 ewes were used, and the experimental diet was fed from 100 days gestation until lambing, with the birth of 172 lambs. The ewes were distributed into three treatments: CTL (control, n = 43) with metabolizable energy (ME) and crude protein (CP) intake according to NRC (1985); ME (energy supplementation, n = 44) plus 21% ME; and MECP (energy/protein supplementation, n = 41) plus 26% ME and CP. Body weight, body condition score, serum hormone concentrations, placental characteristics, lamb performance and behavior, and production efficiency of the ewe from lambing to weaning were measured. ME and MECP ewes were heavier before (p = 0.006) and just after lambing (p = 0.002) and had higher serum triiodothyronine (p = 0.001) and cortisol (p = 0.004) concentrations on the day of lambing. ME ewes had higher placental efficiency (p = 0.036) and lower total cotyledon weight (p = 0.011). ME and MECP diets increased both lamb birth weight (p = 0.015) and weaning weight (p = 0.009). Production efficiency at birth and at weaning was not influenced (p > 0.05) by treatments. Lamb behavior was influenced by the ME and MECP diets, reducing the time to kneel (p ≤ 0.05), to try to stand (p ≤ 0.05), and the latency to stand (p ≤ 0.005). It is concluded that overnutrition in the last third of gestation was positive for the ovine production system, with improved production rates, hormonal profile, placental characteristics, and neonatal behavior.

NonSurgical Embryo Recovery from Estrus-Synchronized or Superovulated Morada Nova Ewes: A Feasible Strategy for Sheep Embryo Banking.

This study assessed the feasibility of in vivo embryo production and nonsurgical embryo recovery (NSER) in Morada Nova ewes (an endangered native Brazilian breed of sheep) subjected to different estrus synchronization and/or superovulation protocols. Ewes received intravaginal sponges soaked with 60 mg medroxyprogesterone acetate (MAP), which were kept in place for six (G6; n = 12), nine (G9; n = 12), or 12 (G12; n = 12) days. Half of the ewes in each group remained estrus synchronized only (SYNCH) and the other half was superovulated (SOV) with 133 mg porcine follicle-stimulating hormone (pFSH). There were no differences (p > 0.05) in antral follicle counts determined with ultrasonography 60 hours before MAP sponge removal (or at the time of the first pFSH dose) among G6 (6.4 ± 0.9), G9 (6.2 ± 0.7), and G12 (5.5 ± 0.6). Estrus responses and NSER success rates did not vary (p > 0.05) among the three progestin-treatment groups of ewes for either estrus-induced or superovulated animals. The onset of estrus occurred 10-12 hours later (p < 0.01) in G9SYNCH ewes compared with G6SYNCH and G12SYNCH, and the duration of estrus was ∼19 hours greater (p < 0.01) in G9SOV than in G6SOV. The average duration of the NSER procedure was 32.6 ± 1.3 minutes. At least one structure was recovered in 85.7% of synchronized and in 87.5% of superovulated ewes. Viable embryo recovery rates were also similar (p > 0.05) for G6 (1.0 ± 0.3 and 2.5 ± 1.5), G9 (1.3 ± 0.5 and 4.8 ± 2.0), and G12 groups (1.0 ± 0.3 and 4.8 ± 2.3; estrus-synchronized and superovulated ewes, respectively). In conclusion, progestogen pretreatment of different durations and NSER can be employed in Morada Nova ewes, resulting in reasonable viable embryo recovery rates in both estrus-synchronized and superovulated animals. Therefore, both techniques are suitable for use in commercial settings as well as small ruminant conservation programs.

Luteotropic effects of human chorionic gonadotropin administered 7.5 days after synchronous estrous induction in Morada Nova ewes.

This study was conducted in ewes to assess effects of human chorionic gonadotropin (hCG) administration after imposing an estrous induction treatment regimen. Ewes (n = 115) were treated with a 60 mg medroxyprogesterone-intravaginal-sponge for 6 d plus 200 IU of equine chorionic gonadotropin (eCG) im and 37.5 µg d-cloprostenol im 36 h before sponge removal (Day 0). After natural mating, ewes having at least one corpus luteum (CL; n = 108) were administered either 1 mL of saline (G-Control; n = 53) or 300 IU of hCG (G-hCG; n = 55) on Day 7.5 after sponge removal (Day 0). Ovarian ultrasonography and blood collection were performed on Days 7.5, 13.5, 17.5, 21.5, and 30.5. Accessory CL (aCL) were observed in 81.5 % (G-hCG) and 0.0 % (G-Control) of ewes (P = 0.0001). Diameter, area, and volume of luteal tissue were greater (P < 0.05) in G-hCG from Day 13.5 to 30.5. Progesterone (P4) concentrations were greater (P < 0.05) on Days 13.5, 17.5, 21.5 and 30.5 for ewes of the G-hCG group. Pregnancy percentage was similar (P = 0.25) between groups [47.1 % (G-control) compared with 60.0 % (G-hCG)], although total number of lambs produced by estrous synchronized ewes was greater (P = 0.005) in ewes of the G-hCG group (90.9 % compared with 66.0 %). In conclusion, hCG administration 7.5 days after sponge removal from Morada Nova ewes during the non-breeding season is an effective treatment to induce aCL formation, improve luteal tissue biometry and P4 concentrations, and to enhance the total number of lambs born.