Human chorionic gonadotropin affects original (ovulatory) and induced (accessory) corpora lutea, progesterone concentrations, and pregnancy rates in anestrous dairy goats.

Two experiments were conducted in acyclic Alpine (A) and Saanen (S) goats that received intravaginal sponges containing 60 mg of medroxyprogesterone acetate for 6 days, as well as 200 IU of eCG and 30 µg d-cloprostenol i.m. 24 h before sponge removal. On day 7 (day 0 = onset of synchronized estrus), all goats were randomly divided into two groups: animals treated with 300 IU of hCG i.m. (hCG; Exp.1: n = 8A; Exp.2: n = 75A + S) and untreated controls (Control; Exp.1: n = 8A; Exp. 2: n = 70A + S). In Exp.2, all goats were artificially inseminated. Transrectal ovarian ultrasonography and blood collection were done on days 7, 10, 13, 17, and 21 (Exp.1), and pregnancy detection on day 60 (Exp.2). Estrus and ovulations occurred in five hCG and seven Control animals. Accessory CL (aCL) were detected in all hCG does. The total luteal area of ovulatory corpora lutea (oCL) increased (P < 0.05) on day 10 in hCG does and remained greater (P < 0.05) than in Control until day 21. Total and high-velocity color Doppler area were greater (P < 0.05) for oCL of hCG does on days 13 and 17. Progesterone concentrations were greater (P < 0.05) in hCG does from days 13 to 21 and related directly to the total luteal and oCL area for the duration of the study in all does. The pregnancy rate was higher (P < 0.05) in hCG than in Control by 22.5 %. Human chorionic gonadotropin given on day 7 of the synchronized estrous cycle positively affected CL function and pregnancy rates in seasonally anovular dairy goats.

Successful transcervical uterine flushing can be performed without or reduced dose of oestradiol benzoate in cervical relaxation protocol in Dorper ewes.

This study assessed the efficiency of cervical relaxation protocol using none, half or full dose (1.0 mg) of oestradiol benzoate in Dorper ewes subjected to non-surgical embryo recovery (NSER). Thirty-six pluriparous ewes received progestogen sponge (60 mg) for 9 days plus eCG administration (300 IU i.m.) 24 hr before sponge removal. Ewes were not mated and were randomly assigned to receive at 16 hr before NSER 37.5 µg d-cloprostenol i.m. and different doses of oestradiol benzoate: 0.0 mg (0EB group; n = 12); 0.5 mg (0.5EB group; n = 12) or 1.0 mg of oestradiol (1.0EB group, n = 12). All ewes received oxytocin (50 IU) i.v. 20 min before NSER, which was performed 8 days after sponge removal. Corpora lutea were counted by transrectal ultrasonography 24 hr before NSER. After procedure, the ewes were kept in natural breeding period to check their post-NSER fertility. NSER was performed in 91.7% (33/36) of the animals with overall fluid recovery efficiency over 97% (p > .05). The cervical transposing with Hegar dilator was longer (p < .05) in 0EB (4.2 ± 0.3 min) compared to 0.5EB (1.7 ± 0.3 min) and 1.0EB group (1.5 ± 0.3 min). The cervical transposing with mandrel/catheter was longer (p < .05) in 0EB (2.4 ± 0.5 min) than 1.0EB group (1.3 ± 0.5 min). Overall duration of uterine flushing was 25.4 min with structure recovery rate of 43.5%, with no difference among groups (p > .05). The post-NSER fertility was higher (p < .05) in 0.0EB (90%) than 0.5EB group (36.4%). In conclusion, NSER can be successfully performed in Dorper ewes by using a cervical relaxation protocol without oestradiol benzoate.

Comparison of the intravenous and intravaginal route of oxytocin administration for cervical dilation protocol and non-surgical embryo recovery in oestrous-induced Santa Inês ewes.

This study compared the effects of intravaginal and intravenous routes of oxytocin (OT) administration in 46 oestrous-induced Santa Inês ewes (6-day treatment with progestin-releasing intravaginal sponges and a single injection of 200 IU of eCG at the time of sponge removal) that underwent transcervical embryo recovery 6-7 days after oestrous onset and mating. All ewes received 37.5 µg of d-cloprostenol via latero-vulvar route, and 1 mg of oestradiol benzoate i.m. 16 hr before and 50 IU of OT 20 min before non-surgical embryo recovery (NSER), with OT being administered intravenously (n = 21) or intravaginally (n = 21). An overall oestrous response was 95.6% (44/46), and adequate cervical retraction could be accomplished in 78.6% (33/42) of ewes. The percentage of successful NSER procedures was 57% (24/42) or 72.7% (24/33) of animals with sufficient cervical retraction. The duration of NSER procedure averaged 28 min (range: 17-40 min) and ~96% of flushing fluid could be recovered (range: 85%-100%). Out of 18 ewes that could not undergo NSER, 12 (66.6%) presented various anatomical barriers, whilst the other 33.4% did not present these barriers and still could not be traversed. Excluding the ewes with those anatomical features, the overall success rate of NSER was 80% (24/30). The route of OT administration had no effect on NSER efficiency or the ease with which transcervical embryo flushing was performed. Both routes of OT administration can be used for cervical dilation protocol. Discarding ewes with anatomical features precluding cervical penetration is highly recommended to increase the efficacy of NSER in sheep.

Tissue composition and allometric growth of carcass of lambs Santa Inês and crossbreed with breed Dorper.

This study aimed to assess the tissue composition and allometric growth of carcasses of Santa Inês and crossbred Dorper x Santa Inês lambs confined for different periods at three body weight classes. Sixty-four lambs from Santa Inês (SI) and crossbred Dorper x Santa Inês (DSI) were slaughtered. The carcasses were refrigerated at 4 °C for 24 h, and half of the right side carcass was divided into five primary cuts, which were then dissected into bone, muscle, and fat. The corrected cold carcass weight (CCWc) was calculated based on the sum of the cuts. There was no effect of the interactions evaluated (P > 0.05) among the factors tested. CCWc, muscle (kg), fat (kg), bone (%), M:F, M:B, F:B, and M+F:B were influenced by the lambs' genetic group (P < 0.05). An effect of body weight at the beginning of confinement was found only for CCWc, muscle (kg), fat (kg), bone (kg), bone (%), and M:F. The crossbreeding of Santa Inês with breeds Dorper promotes improvements in the qualitative characteristics of the carcass. To obtain better relationships of the quantitative characteristics of the carcass, of sheep introduced in confinements with larger weights, the slaughter weight must be adjusted to that initial weight.