The use of female estrogenized goats as sexual stimulator of crossbred dairy males subsequently exposed to acyclic goats during two phases of the anestrous season.

This research evaluated the possible influence of exposure of male goats to estrogenized female goats ("female effect") upon males' sexual behavior [appetitive (ASB) & consummatory (CSB)], as well as the induction of reproductive activity of crossbred dairy female goats exposed to such treated males ("male effect") during the early and deep anestrous periods. Crossbred dairy adult male goats (n = 12; 24-48 mo. old) and 80 anovulatory crossbred dairy adult female goats (34-50 mo. old) were used during two experimental periods: March to April and April to May. First, males were separated into four groups (n = 3 each), roughly homogeneous regarding body weight and body condition score and randomly assigned to four experimental groups. The first two groups included males + estrogenized females, then such males were exposed to anestrous females either during March (group 1: three males; 20 females; EFEM-MAR), or during April (group 2: three males; 20 females; EFEM-APR). The second two groups were respective control groups: Males + non-treated-anestrous females, and then such males exposed to acyclic females either during March (group 3: three males; 20 females; CONT-MAR) or April (group 4: three males; 20 females; CONT-APR). Once the male-to-female contact was established, both odor (ODT) and behavior (BEHT) tests (2 d × 2 h) were performed during both anestrous periods. On day 10 after introduction of the males, in both anestrous periods, one ultrasonography scanning ("US") was performed to quantify the presence, number and size of corpus luteum (US-CL) to determine the effectiveness of the "male effect" and indicators of ovarian activity. Then, on day 45 after introduction of the males, a second US was performed to evaluate pregnancy rate (US-PREG). The EFEM-males, regardless of the phase of the anestrous cycle, had an increased (P < 0.05) odor intensity with respect to the control groups. In addition, while an increased (P < 0.05) ASB occurred in the EFEM-males, no CSB differences (P > 0.05) arose when treatments were compared, neither in March-April nor in April-May. The EFEM-males exposed to acyclic goats in March-April (i.e. early anestrous period), promoted not only the largest estrus and ovulatory responses (P < 0.05), but also the largest pregnancy rate (P < 0.05) in these previously anestrus goats, suggesting that in April-May (i.e. profound anestrous), the presence of active males was not enough to completely suppress cyclic reproductive arrest. This study generates interesting out-of-season reproductive outcomes in a goat population with a large proportion of highly seasonal dairy breeds (i.e. Alpine, Saanen and Toggenburg), augmenting the possibility to expand milk production and the economic income of goat producers across the year. Besides, this practice may serve as an interesting reproductive tool to increase the sustainability of marginal goat production systems under semiarid conditions.

Semen deposition by cervical, transcervical and intrauterine route for fixed-time artificial insemination (FTAI) in the ewe.

Semen deposition through the cervix into the uterus is a difficult technique in ewes and represents the main limiting factor for insemination in this species. The objective of this study was to evaluate the pregnancy rate achieved with a new transcervical insemination method in comparison with conventional cervical and laparoscopic intrauterine techniques. A total of 586 multiparous Corriedale ewes were synchronized for fixed time artificial insemination (FTAI) performed by cervical, transcervical, or intrauterine route at 46-50 h or 52-56 h after progesterone device removal in a 3 × 2 factorial design. Pregnancy rate was affected by the insemination technique and by the moment of FTAI (P < 0.05), without interaction (P= NS). Overall, the fertility was improved as semen deposition was deeper and insemination was delayed. For transcervical insemination, pregnancy rate was intermediate (42.3%; P= NS) between cervical and intrauterine route (36.0% and 50.2%; P < 0.05), and was greater for those ewes inseminated beyond 4 cm into the cervix (60.0% versus 35.1% for insemination beyond or within 4 cm into the cervix, respectively; P < 0.05). Semen deposition beyond 4 cm into the cervix was achieved only in 28.8% of the females receiving transcervical insemination. This method was more time-consuming than cervical or laparoscopic insemination (11.4 ± 1.6 versus 85.5 ± 7.5 and 56.8 ± 5.6 ewes inseminated per hour, respectively; P < 0.05). In summary, greater pregnancy rate using FTAI is obtained when semen is placed into the uterus, which was achieved in all females only through laparoscopy. Further improvements are required for transcervical insemination to be applied in large-scale FTAI programs in Corriedale ewes.

Exposure of sexually inactive males to estrogenized females increased the investigative and consummatory sexual behavior.

Two trials were conducted to evaluate the effect of diverse socio-sexual cues upon male sexual behavior and the reproductive performance of anestrous does (AD). Trials were conducted in northern Mexico (26°N) during the natural anestrous season (Feb-Mar) with crossbred dairy bucks. In Experiment 1, sexually inactive bucks (SIB, n=12) were randomly allotted to three groups, four males/group: a) DEE 9novelty stimulation) - daily exchange of estrogenized females (EF) 12&12h, b) NEE (no novelty stimulation) - no-exchange of EF, 24h, or c) CON (saline-treated_ -daily exchange of AF 12&12h. Sexually active bucks (SAB) from the DEE, NEE and CON groups were subsequently exposed to AD (n=72; n=24/group) and the reproductive outcomes were recorded. In Experiment 2, SAB (n=12; n=6/group) were randomly divided in: 1) B+EF - males+four-EF exposed to AF (n=36), and 2) B+NEF; males+four-saline-treated AD and exposed to AD (n=36). Prior to the onset of the experimental breeding in both experiments, the investigative (ISB), consummatory (CSB) and resting (RSB) sexual behavior of males were quantified (2h×d×2d). Sexual behaviors considered were: ISB - flehmen, ano-genital sniffing, approaches, vocalizations, kicking, penis extrusion, CSB; mount attempts and mounts, and RSB - isolation, attempted escape, aggression and distractions. While EF were an effective stimulus (P<0.05) for evoking mounting in SIB males, daily exchange of estrous does used to stimulate males promoted an enhanced response (P<0.05) in terms of both ISB and CSB. After being exposed to AD, the B+EF bucks induced an earlier estrous response (P<0.05) as compared with the B+NEF bucks. The untreated females did not induce any sexual activity in males and stimulation of ovarian function did not occur when saline treated (CON) AD were exposed to AD. Also, the B+EF group induced an enhanced increase (P<0.05) of the male ISB and CSB, inducing in turn an increase percentage onset of estrus in does that had previously been anestrus (P<0.05).

Reproductive outcomes of Alpine goats primed with progesterone and treated with human chorionic gonadotropin during the anestrus-to-estrus transition season.

This study aimed to determine the possible effects of a single injection of human chorionic gonadotropin (hCG) as a means for estrus induction in acyclic French-Alpine goats during the reproductive transition period at 25°N, 103°W. The potential effects of hCG upon ovarian function and reproductive performance of goats were also assessed. Multiparous acyclic French-Alpine goats (n = 39; 37.4 ± 8 .5 kg) were primed with 20mg progesterone (P4) 1 day prior to hCG administration. Thereafter, does were treated either with saline (hCG-0; n = 10), 50 (hCG-50; n = 9), 100 (hCG-100; n = 10), or 300 IU of hCG (hCG-300; n = 10). Ovarian structures and pregnancy were monitored by transrectal ultrasonography. In addition, after hCG application, goats were monitored twice daily (0800 and 1800 h) to detect estrus signs, with the use of aproned, sexually active bucks treated with testosterone. Goats were bred 12h after the onset of estrus. Two days after hCG administration, the number of large follicles was higher (P < 0.05) in the hCG-50 and hCG-300 groups (1.7 ± 0.1 and 1.8 ± 0.2, respectively) compared with the hCG-100 and hCG-0 groups (1.4 ± 0.2 and 1.1 ± 0.1, respectively). Although none of the hCG-0-goats depicted estrus, the estrus response from the hCG-50, hCG-100, and hCG-300 groups over the 7-d breeding period was 67%, 100%, and 90%, respectively (P > 0.05), being always accompanied by ovulation. Pregnancy rate (67, 100, and 70%), kidding rate (55%, 80%, and 70%), and litter size (1.6 ± 0.5, 1.5 ± 0.5, and 1.5 ± 0.5) for hCG-50, hCG-100, and hCG-300, respectively, did not differ among the hCG-treated does. Therefore, the combined use of P4-priming plus a 100-IU hCG injection is an effective protocol for inducing estrus in non-cycling Alpine goats during the anestrus-to-estrus transition period, which is of key importance for both goat producers and industrializers.