Time of day modified the time required for semen collection with electroejaculation and slightly affected the quality of fresh semen in rams.

The aim was to compare some stress responses to electroejaculation (EE), and the quality of fresh semen, when ram semen is collected at dawn (06:00 h), noon (12:00 h), or evening (18:00 h). Twelve Corriedale rams were used, and semen was collected from four rams at each study time on three different days, with a Latin-square design. The time required for EE, the number of vocalizations emitted, heart rate, and rectal temperature were recorded, and fresh semen was evaluated. The time required for EE was shorter at evening than at dawn and noon (399.3 s, 480.6 s, and 460.2 s respectively; pooled SEM = 72.1; P = 0.03). The percentage of sperm with progressive motility was greater at noon than dawn (59.7% and 50.3%; pooled SEM = 5.8; P = 0.05). Curvilinear velocity was greater at dawn than evening (117.0 µm/s and 95.5 µm/s; pooled SEM = 7.1; P = 0.04), slow linear velocity was greater at evening than at dawn and noon (13.1 µm/s, 9.3 µm/s, and 8.5 µm/s respectively; pooled SEM = 1.7, P = 0.05), and the slow average path velocity was greater at evening than dawn and noon (16.2 µm/s, 11.7 µm/s, and 10.8 µm/s respectively; pooled SEM = 1.9, P = 0.05). In conclusion, the collection time modified the time required for electroejaculation and had only slight effects on the quality of fresh semen. Overall, the time of the day appears to have only slight effects on semen collection and quality.

Adult and yearling pampas deer stags (Ozotoceros bezoarticus) display mild reproductive seasonal patterns with maximum values in autumn.

The pampas deer is an endangered species, from which reproductive biology little is known. We aimed to describe and compare the reproductive seasonal patterns of adult and yearling pampas deer stags throughout the year, including morphological traits, testosterone concentration, sperm morphology and cryoresistance pattern changes. Six adult (AS) and five yearling (YS) stags were captured with anesthetic darts once in winter, spring, summer and autumn to study morphological variables, serum testosterone and semen. Adult males were heavier, their neck girth tended to be greater and their testosterone concentration was higher than in YS. Animals were heavier in summer and autumn. Neck girth and testosterone concentration were greater in autumn. Scrotal circumference, testicular volume and gonado-somatic index varied with seasons, decreasing from winter to spring, increasing in summer and remaining in greater values in autumn. Sperm quality had maximum values from summer to winter. However, the cryoresistance ratio of motility score was greater in spring. In conclusion, in the captivity conditions, pampas deer stags seems to present a light seasonal reproductive pattern, with maximum testis size, testosterone secretion and fresh semen quality in autumn. Nevertheless, sperm cryoresistance ratio seemed to remain stable along the year. Although YS were still growing, they achieved similar semen quality than AS.

Treatment of male goats with equine chorionic gonadotrophin during the non-breeding season does not affect their sperm characteristics during the subsequent breeding season.

Equine chorionic gonadotrophin (eCG) is a hormone having FSH/LH effects. It can be used to enhance sperm quality in male goats (bucks) during the non-breeding season. In a previous study carried out during the non-breeding season, we treated ten bucks with eCG (leaving nine untreated animals as control). Over a 20-day period, the treated bucks received an initial dose of 800 IU of eCG, followed by four doses of 500 IU. We found eCG enhanced semen quality, however, as also happens in female goats (does), eCG also induced a high titer of anti-eCG antibodies. In does, this lowers fertility. The aim of the present study was to determine if the eCG treatment carried out on bucks during the non-breeding season had any negative effects on their reproductive status during the following breeding season. We measured serum concentration of testosterone and anti-eCG antibody, as well as key testicular and seminal characteristics. This study commenced 91 days after the final dose of eCG in the previous study. The anti-eCG titer was higher in the treatment bucks than in untreated ones (181.7 ± 61.3 ng/µL vs 31.1 ± 10.7 ng/µL; P < 0.05). However, there were no significant differences between treated and untreated bucks in testosterone concentration, scrotal circumference, testes pixel intensity, fresh and thawed semen characteristics, or sperm cryoresistance. So, although the eCG-treated bucks had greater titers of anti-eCG antibodies, their reproductive pattern was unaffected.

Equine Chorionic Gonadotropin (eCG) improves bucks' semen quality during the nonbreeding season.

In most goat breeds, testosterone serum concentration and semen quality decrease during the nonbreeding season. However, bucks reproductive activity may be stimulated with the administration of equine chorionic gonadotropin (eCG). Therefore, the aim of this study was to determine whether the repeated administration of eCG stimulates the reproductive status of bucks during the nonbreeding season. The study was performed with 19 bucks that were assigned to a group that was treated with eCG (GeCG) and an untreated control group (GCon). The GeCG bucks received an initial dose of 800 IU of eCG (Day 0), followed by four doses of 500 IU administered every 5 days beginning on Day 5. Serum testosterone and anti-eCG antibody concentrations, testicular and seminal traits were determined until Day 60. Testosterone concentration (from Day 3 to 21: p < 0.0001), anti-eCG titre (from Day 12 to 44: p ≤ 0.01), percentage of motile spermatozoa (Day 6: p = 0.006 and 14: p = 0.001) and of spermatozoa with progressive motility (Day 6: p = 0.01 and 14: p = 0.002) and the percentage of spermatozoa with functional membrane (Day 6: p = 0.02 and 22: p = 0.008) were higher in GeCG than in GCon bucks. Also in frozen-thawed samples, the percentage of motile spermatozoa tended to be higher in GeCG than that of GCon bucks (p = 0.07). In conclusion, the administration of eCG during the nonbreeding season stimulated the secretion of testosterone and improved fresh and possibly frozen-thawed semen quality. However, it also resulted in an increase in anti-eCG antibody titre.

Sperm collection by transrectal ultrasound-guided massage of the accessory sex glands is less stressful than electroejaculation without altering sperm characteristics in conscious goat bucks.

In anesthetized non-domestic ruminants transrectal ultrasound-guided massage of the accessory sex glands (TUMASG) is an alternative method to collect semen slightly less stressful than electroejaculation (EE). However, some sperm characteristics are better when semen is collected with EE than with TUMASG. As anesthesia reduces the response to stressors, the advantages of TUMASG may be reduced in anesthetized animals, and thus, TUMASG may be even more advantageous in conscious animals. Therefore, the aim of the present study was to compare the stress response and the characteristics of the sperm collected with TUMASG and EE in conscious goat bucks. Semen was collected in 10 bucks with both procedures. During each procedure, the time required for ejaculation, the number of electric pulses applied and the number of vocalizations were recorded. Rectal temperature, heart rate, serum cortisol concentration, biochemical and hematological parameters were measured before and after each procedure. Sperm characteristics [ejaculated volume, sperm concentration, sperm mass motility (scale 0-5), sperm vigor (scale 0-5), the percentages of motile and progressive motile sperm, of sperm vitality, of sperm with plasma membrane integrity, and with acrosome damage and morphological abnormalities] were also determined. Electroejaculation required more electric pulses than TUMASG (P < 0.0001), but TUMASG took more time than EE (P < 0.0001). The EE provoked more vocalizations (P = 0.02) and a greater increase of cortisol concentrations than TUMASG (P = 0.04). Heart rate also tended to be greater with EE than with TUMASG (P = 0.07). The sperm characteristics did not differ between TUMASG and EE. In conclusion, TUMASG was less stressful and probably less painful than EE without affecting the semen quality. Thus, although it required more time, TUMASG is an alternative procedure to decrease the welfare concerns raised by EE in conscious goat bucks.

Oxytocin administration before sperm collection by transrectal ultrasonic-guided massage of the accessory sex glands in mouflons and bucks.

Transrectal ultrasonic-guided massage of the accessory sex glands (TUMASG) is an alternative technique for sperm collection which decreases negative animal welfare concerns of electroejaculation. However, quality of collected sperm with TUMASG is less than that collected by electroejaculation. Utilisation of TUMASG may not, however, induce strong muscular contractions, so administration of oxytocin before the procedure may improve sperm quality. Therefore, two studies were designed to determine if administration of oxytocin before TUMASG improves the procedure and quality of the collected semen. The first study was performed with anaesthetised mouflons, and the second with non-anaesthetised Gabon bucks. Time length, number of electric pulses applied and numbers of vocalizations were recorded, and sperm characteristics were analysed. The number of electrical pulses and sperm characteristics did not differ with oxytocin administration in mouflons. However, oxytocin administration decreased time length (P=0.02) and tended to decrease the number of electric pulses needed for induction of ejaculation (P=0.08) in bucks. The number of vocalizations and sperm variables did not differ when the two procedures were used. In conclusion, oxytocin administration before TUMASG shortened the procedure and tended to decrease the number of electrical pulses needed to induce ejaculation in conscious bucks, thus, decreasing welfare concerns for the animals in which TUMASG is used. Therefore, its routine inclusion in this species should be considered.

Reproductive and sexual behaviour development of dam or artificially reared male lambs.

The objective of this study was to determine if artificially reared male lambs differ from those reared by their mothers in their reproductive development and sexual behaviour during the first breeding season and in their serum testosterone to a GnRH challenge at the end of the first breeding season. Lambs were assigned to two experimental groups: 1) artificially reared lambs, separated from their dams 24-36h after birth (Week 0) and fed sheep milk until 10weeks of age (group AR, n=14); and 2) lambs reared by their dams until 10weeks of age (group DR, n=13). Reproductive parameters and sexual behaviour were recorded from Weeks 9 to 39. The GnRH challenge was performed on Week 40. Body weight, scrotal circumference, gonado-somatic index, testosterone concentration and sperm parameters were unaffected by group, but increased with age (P<0.0001). Lambs reared by their mothers had greater values of gonado-somatic index on Weeks 9, 16 and 19 (P<0.05), and tended to reach puberty earlier than AR (22.9±0.7 vs. 25.1±1.1weeks, respectively, P=0.087). Lambs reared by their mothers presented more lateral approaches and mount attempts than AR (P<0.05), and DR lambs presented more mounts on Weeks 32 and 39 than AR (P<0.05). Blood testosterone concentrations 3.5 and 4h after the GnRH challenge were higher in AR than in DR lambs (P<0.05). In conclusion mother rearing promoted sexual behaviour and reproductive performance of male lambs.