Effect of nutraceutical supplementation on semen quality in stallions.

BACKGROUND: The use of reproductive biotechnologies in equine practice has shown that some stallions are subfertile, so ways to improve fertility have been sought. OBJECTIVE: This study aimed to evaluate the effect of nutraceutical supplementation on improving semen quality in Quarter Horse stallions. METHODS: Semen from six Quarter Horse stallions was assessed for 4 months every 20 days using the computer-assisted semen analysis system. They were evaluated for 60 days before supplementation; then, the same stallions were re-evaluated for 60 days with nutraceutical supplementation (30 g/day). RESULTS: Volume showed no significant difference (p > 0.05) with nutraceuticals. Sperm concentration (10x6 ) was significantly higher with supplementation (339.4 ± 17.5 sperm/mL) than without supplementation (224.6 ± 19.9). Sperm abnormalities (%) were significantly (p < 0.05) lower with supplementation (14.3 ± 0.6) than without supplementation (19.1 ± 0.4). Sperm kinematic parameters, total motility (TM), progressive motility (PM), rectilinear velocity (VSL), the velocity of the trajectory (VAP) and curvilinear velocity (VCL), were significantly better with supplementation (p < 0.05). CONCLUSIONS: Based on the results, it is concluded that nutraceutical supplementation improved semen parameters in Quarter Horse stallions.

Multifaceted Interplay among Social Dominance, Body Condition, Appetitive and Consummatory Sexual Behaviors, and Semen Quality in Dorper Rams during Out-Of-Season and Transition Periods.

Dorper rams (n = 24) were evaluated during the sexual resting season to determine their social rank (SR), either high (HSR) or low (LSR), under intensive management conditions in northern Mexico (25° N). Aggressive behaviors were quantified during male-to-male interactions, and appetitive and consummatory sexual behaviors during male-to-female interactions. Morphometric, live weight (LW), and body condition score (BCS) were recorded. During the early reproductive season, male-to-female behaviors were newly itemized simultaneously by seminal quality and quantity sampling. Finally, the dependent variables of the hemogram components were also quantified. Neither LW (61.25 ± 2.4 kg) nor morphometric variables differed between SR groups. However, BCS (2.25 vs. 2.66 u), sexual behaviors (i.e., approaches: 59.6 vs. 21.73 n, mating with ejaculation: 77.7 vs. 42.86 %, latency to ejaculation: 16.6 vs. 143.07 s), ejaculate volume (0.57 vs. 0.23 mL), and hemogram components favored the HSR rams (p < 0.05). Moreover, in their first male-to-female interaction, >50% of the LSR rams failed to display any sexual activity. HSR rams displayed a greater number of threatening behaviors, managing to displace LSR rams when exposed to estrus ewes during the male sexual resting season; more sexual behaviors; and an increased seminal volume in a non-live weight-dependent fashion.

Short communication: reproductive response to concentrate supplementation of mixed-breed goats on rangeland.

The effect of concentrate supplementation to crossbred goats on rangeland during the dry period on their reproductive performance was investigated. Goats were assigned into two groups: a concentrate supplemented (S; n = 91) group and an unsupplemented (UNS; n = 118) group. S goats received 350 g/day of concentrate per head, 30 days prior to breeding (flushing in winter) and 30 days during the last trimester of pregnancy. UNS goats presented a lower (P < 0.01) liveweight at the onset of the breeding period than did the S group (38.2 ± 3.7 vs. 44.4 ± 3.6 kg). Average daily gains during pregnancy were higher (P < 0.01) in the S group than UNS goats (15.5 ± 1.2 vs. - 0.5 ± 5.1 g/d). S goats had a higher (P < 0.01) kidding rate (87.1%) than the UNS goats (54.7%). Litter size for UNS and S goats was 1.39 and 2.00, respectively (P < 0.01). Serum triiodothyronine, tetraiodothyronine, and cortisol concentration at the end of the flushing period were not affected by concentrate supplementation. Serum glucose (88.7 ± 3.8 vs. 95.7 ± 5.3 mg/dL), total protein (6.9 ± 1.1 vs. 8.2 ± 1.2 mg/dL), and blood urea nitrogen (17.1 vs. 21.0 ± 4.3 mg/dL) concentrations were lower for UNS goats as compared with S goats. In conclusion, concentrate supplementation in crossbred goats on rangeland markedly improved body mass changes during gestation and the reproductive performance, which implies that malnutrition is a major barrier affecting fertility of goats and liveweight of kids in this rangeland.

Ovarian response is not affected by the stage of seasonal anestrus or breed of goats when using a progesterone injection plus human chorionic gonadotropin-based protocol.

The aim of this study was to evaluate the effect of the stage of seasonal anestrus and breed on ovarian response in non-estrous cycling goats using a progesterone (P4) injection plus human chorionic gonadotropin (hCG)-based protocol. In Experiment 1, non-estrous cycling local Mexican goats were treated with 20 mg of P4 plus 100 IU of hCG injections 24 h apart during April (early anestrus, n = 13) or June (late anestrus, n = 12). The estrous response, interval from hCG-to-estrus, and interval to ovulation were not affected by season (P > 0.05). In addition, the size of the follicle from which ovulation occurred and the size of the corpus luteum were not different between the two stages of seasonal anestrus (P > 0.05). In Experiment 2, the estrous response was compared between multiparous non-estrous cycling local Mexican (n = 18) and Alpine (n = 19) goats in which stage of the estrous cycle was synchronized using the same P4+hCG protocol as in Experiment 1. Neither the onset of estrus nor the time of ovulation differed between breeds, and the estrus-to-ovulation interval also was similar for both breeds (P > 0.05). The diameter of the dominant follicle at the time of ovulation was similar between local and Alpine goats (P > 0.05). In addition, the pregnancy rate was not different for both local and Alpine goats (P > 0.05). In conclusion, results of this study indicate that the stage of seasonal anestrus or breed do not modify estrous and ovarian response in non-estrous cyclic goats synchronized with a P4 injection plus hCG-based protocol.

Use of injectable progesterone and hCG for fixed-time artificial insemination during the non-breeding season in goats.

The objective of this study was to determine the estrous response and the moment of ovulation and fertility after a progesterone (P4) priming plus human chorionic gonadotropin (hCG) administration in multiparous and nulliparous goats. Therefore, two experiments were conducted during non-breeding season (April and May, 26° N) and all the animals received a single injection of 20 mg of P4 and 100 IU of hCG 24 h later. In Experiment 1, 13 multiparous and 9 nulliparous goats were subjected to estrus detection twice a day from P4 administration, and their ovaries were scanned by transrectal ultrasonography every 12 h from the onset of estrus to determine ovulation. The proportion of goats in estrus did not differ between multiparous and nulliparous females. The onset of estrus (60.5 ±â€¯12.4 h vs. 52.0 ±â€¯5.2 h after hCG administration) and the moment of ovulation (91.5 ±â€¯10.3 h vs. 85.3 ±â€¯11.5 h) were also similar in multiparous and nulliparous goats. In Experiment 2, a total of 299 multiparous and nulliparous goats managed under intensive (n = 112 and 41 goats, respectively) or extensive (n = 85 and 61 goats, respectively) production systems were divided to receive a fixed-time artificial insemination (FTAI) with fresh semen at 60 or 72 h after hCG administration. The pregnancy rate did not differ significantly between multiparous and nulliparous goats in both production systems. Nonetheless, in the intensive system pregnancy rate was affected by the moment of insemination (P < 0.05). In this system, the pregnancy rate was higher in goats inseminated at 60 h than in 72 h (55.6%, 44/79 vs. 35.1%, 26/74, respectively; P < 0.05). On the contrary, in the extensive system the pregnancy rate was not affected by the time of insemination (29.4%, 23/78 vs. 22.0%, 15/68). To conclude, both the ovulatory response and the pregnancy rate after a single P4 injection plus hCG was similar between multiparous and nulliparous goats during anovulatory season. Although the pregnancy rate was not affected by the time of insemination in the extensive production system, under intensive conditions FTAI should be performed at 60 h after hCG treatment.