Intravaginal progesterone device reinsertion during the early luteal phase affects luteal function and embryo yield in superovulated ewes.

This study checked the efficacy of progesterone (P4) device reinsertion during the early luteal phase on luteal function and embryo yield in superovulated crossbred ewes. Twenty multiparous ewes received an intravaginal P4 device for nine days (D0 to D9) followed by six decreasing doses (25, 25, 15, 15, 10, 10%) of 133 mg pFSH i.m. at 12 h intervals, starting 60 h before P4 device removal. Ewes were naturally mated at 12 h intervals while in estrus. On D13, ewes with viable corpora lutea (CL; n = 19) were equally allocated for receiving their P4 device reinsertion (G-P4; n = 10) or not (G-Control; n = 9). On D17, the P4 device was removed, and all females received the cervical relaxation protocol 16 h to 20 min before non-surgical embryo recovery. CL count and their functionality classification were performed on D13 and D17 by transrectal B-mode and color Doppler ultrasonography (US). Plasma P4 concentrations (ng/mL) of G-P4 ewes increased (P < 0.05) over the days, being greater on D17 (9.2 ± 2.8) than on D9 (1.9 ± 0.7) and D13 (1.6 ± 0.4). The overall CL count per ewe tended to be greater (P = 0.09) in G-P4 compared with G-Control. The occurrence of premature regression of corpora lutea did not differ (P > 0.05) between G-P4 (30.0%) and G-Control (44.4%). The number of ova/embryos recovered was greater (P < 0.05) in G-P4 (11.6 ± 2.9) compared with G-Control (3.7 ± 2.0), respectively. Altogether, the reinsertion of the P4 device for four days after superovulation in ewes promotes greater P4 concentrations, resulting in greater ova/embryos recovered.

Effects of hCG administration on accessory corpus luteum formation and progesterone production in estrous-induced nulliparous Santa Inês ewes.

The effect of hCG administration on accessory corpus luteum (ACL) formation, CL area, and plasma progesterone (P4) concentration (ng/mL) seven days after breeding was studied in nulliparous Santa Inês sheep. Intravaginal 60 mg MAP sponges were inserted into ewes for six days and 300 IU eCG i.m. and 30 µg d-cloprostenol latero-vulvar were administered 24 h before sponge removal. Ewes were naturally bred and, seven days after first mating (Day 0; D0), were treated with either 250 IU hCG (hCG group; n = 7) or 1 mL saline solution (control group; n = 7). Blood was collected to determine plasma P4 concentrations and sonograms were performed on Days 7, 10, 13, 16, 19, and 22. Number of CL on D7 was similar (P > 0.05) between hCG (1.3 ± 0.5) and control (1.3 ± 0.5) groups; however, on D13, it was greater (P < 0.05) in the hCG group (2.3 ± 0.5) than in the control group (1.3 ± 0.5). A greater (P < 0.05) luteal tissue area was detected in hCG-treated ewes (n = 4) on Days 16 to 22 than in the animals in the control group (n = 7). Plasma P4 concentration on D13 to D22 was higher (P < 0.05) in hCG-treated animals than in control ewes. Administration of hCG seven days after estrus onset efficiently induced accessory CL formation in ewes, increasing luteal tissue area and plasma P4 concentration.

Protected fatty acid supplementation during estrus synchronization treatment on reproductive parameters of dairy goats.

This study evaluated the effect of the protected fatty acid inclusion during estrus synchronization on reproductive parameters. Goats (n = 32) received progestagen sponges for 6 days and 200 IU equine chorionic gonadotropin and 30 µg d-cloprostenol were given on Day 5. No difference was found among control (C), 1% protected fatty acid inclusion (C + 1%) or 4% protected fatty acid inclusion (C + 4%) groups, respectively, in estrus (100.0, 100.0 or 90.9%), estrus duration (31.6 ± 12.3; 43.2 ± 12.9 or 40.8 ± 14.1 h), animals ovulating (100.0, 90.0 or 100.0%) or ovulation rate (1.3 ± 0.5; 1.1 ± 0.3 or 1.2 ± 0.4). The interval from sponge removal to ovulation and from estrus to ovulation, respectively, were shorter for C + 4% (45.2 ± 8.0 h; 18.3 ± 11.0 h) compared with C (56.3 ± 12.6 h; 30.6 ± 10.5 h) or C + 1% (57.7 ± 8.7 h; 30.3 ± 11.1 h). The average ovulatory follicle diameter was smaller for C + 4% (6.2 ± 0.7 mm) than C (7.5 ± 0.8 mm), but similar to C + 1% (7.0 ± 1.5 mm). Insulin, insulin-like growth factor 1, glucose and progesterone concentrations were similar among groups. The inclusion of protected fatty acid during synchronization treatment promoted no benefits on ovulation rate, but 4% anticipated the ovulation time.