Female cats are known to be seasonal breeders and male cats annual breeders. Despite this, there are limited data on the influence of breeding season (BS) on hormone concentration and semen quality in the male cat. This study compared plasma concentrations of LH and testosterone (T), and semen quality during the non-breeding season (NBS) and BS in five male cats subject to natural hours of daylight but a constant environmental temperature. Plasma LH and T concentrations were higher during the BS in 2/35 and 3/5 cats, respectively, although when comparing both hormones combined, values were higher during the BS than the NBS in all cats (p < 0.01). There were no significant differences in the percentage of abnormal sperm between the cats. Overall, semen quality was superior during the BS with larger semen volume in 2/5, sperm motility in 2/5 and sperm viability in 3/5 cats. Although there was a clear seasonal effect on hormone secretion and semen quality, during the NBS all cats were likely to have been fertile.
Plasma progesterone (P(4)) concentrations are maintained in pregnant cats until parturition, but become low in pseudopregnant cats 40-45 days after infertile mating. This difference in P(4) concentrations is considered to be due to P(4) secretion by the placenta of pregnant cats. Therefore, to clarify these points, we performed ovariectomy (OVX) at various stages of pregnancy, examined the pregnancy status and measured LH and P(4) concentrations in peripheral, ovarian and uterine venous blood. After OVX, abortion occurred in 100% (5/5), 80% (4/5), 40% (2/5) and 60% (3/5) of Groups I (Day 35), II (Day 40), III (Day 45) and IV (Day 50) cats, respectively. In the remaining cats, normal delivery took place on days 63-69 [mean, 66.1 +/- 1.1 (SE)] of pregnancy. The time to abortion after OVX was 4-8 (mean, 5.6 +/- 0.8), 3-17 (mean, 8.0 +/- 3.6), 10 and 11, and 2-4 (mean, 3.0 +/- 0.7) days in Groups I, II, III and IV, respectively. The plasma P(4) concentrations were 1-2 ng/ml in all groups on the day after OVX, decreasing to less than 1 ng/ml from the 2nd day onwards. The concentrations of P(4) in ovarian venous blood at the time of OVX decreased with the stage of pregnancy, but were clearly higher than those in peripheral blood. The plasma P(4) concentrations in uterine venous blood were similar to those in peripheral blood. These results suggest that peripheral P(4) in pregnant cats is the result of P(4) secretion secreted only by the ovarian corpus luteum, not by the placenta, but indicate that either P(4) is not essential for the maintenance of pregnancy in cats from day 40-45 of pregnancy onwards, or that the placenta provides a local source of P(4) that does not appear in measurable amounts in the peripheral circulation.
ABSTRACT. The freezing conditions for preparation of frozen canine semen by the plunging method were investigated with regard to the period of sensitization in liquid nitrogen (LN 2 ) vapor and the height from LN 2 , and the semen qualities after thawing were compared with those of canine semen prepared by the simple freezer method previously reported by us. In the plunging method, 9 semen straws were prepared under the same conditions, horizontally kept at 5, 7, and 10 cm above the LN 2 surface in a styrene foam box for 5, 10, and 15 min, and then plunged into LN 2 . The semen qualities immediately after thawing were high in the 7 cm/10 min (cooling rate: -4 to -22°C/min) and 10 cm/15 min groups (cooling rate: -6 to -10°C/min). On comparison of frozen semen prepared by the plunging method (7 cm/10 min) with frozen semen prepared by the simple freezer method, sperm motility and viability were significantly higher for the frozen semen prepared by the plunging method. The cooling rate in freezing was higher for the simple freezer method (cooling rate: -6 to -50.9°C/min) than the plunging method. Based on these findings, horizontal placement of canine semen straws above LN 2 to reduce the temperature at a slow cooling rate of about -10°C/min, followed by plunging into LN 2 after sensitization for 10-15 min, provides good semen qualities after thawing. KEY WORDS: canine, cryopreservation, liquid nitrogen vapor, plunging method, simple freezer method.J. Vet. Med. Sci. 68(10): 1055-1061, 2006 Studies of frozen canine semen have not progressed because canine sperm is readily impaired by low-temperature sensitization compared to the sperm of other mammals [4]. It has recently been clarified that the addition of surfactants, such as Orvus ES paste (OEP: Nova Chemical Sales Inc., Scituate, MA, U.S.A.) [19][20][21] and Equex STM paste [12,14,16], to frozen semen extender containing egg yolk protects the acrosome cap after thawing, which prolongs the lifespan of sperm after thawing and increases the conception rate after artificial insemination. However, the preparation method of frozen canine semen varies among researchers, and factors that may affect the qualities of frozen semen after thawing, such as the diluent composition [2,6,13,16,17], dilution rate [9], cryoprotectant concentration [2], packaging (straw thickness) [8], freezing method (cooling rate) [1,8,10,11,15,16,18,23], and thawing method (warming rate) [8,10,23], have been investigated.For freezing, we previously used a conventional simpletype quick LNG freezer (FA-1652, Fujihira Industry Co., Ltd., Tokyo, Japan) and obtained a high conception rate (90%) by intrauterine insemination using a thawed semen preparation [19][20][21]. This instrument, developed for the preparation of frozen bovine semen, is capable of preparing a large amount of frozen semen in a single operation. However, the opportunity to prepare such large amounts of frozen canine semen is rare. In another simple method, called the plunging method, semen is exposed to liquid nitrogen (LN 2 ) vap...
ABSTRACT. We observed the influences of low-temperature storage of the feline epididymis on the epididymal semen qualities before and after cryopreservation to identify the optimal duration for low-temperature storage of the epididymis. After excision, the feline epididymis was stored at 4 C for 0-72 hr and then subjected to epididymal sperm collection. When sperm from the refrigerated cauda epididymis were frozen and thawed, there was no significant difference in sperm motility between the 0-and 24-hr low-temperature storage groups, but sperm motility was significantly decreased in the 48-hr storage group. The above findings suggested that low-temperature storage of the epididymis until 24 hr is useful for frozen sperm collected from the feline cauda epididymis.KEY WORDS: cryopreservation, epididymal sperm, feline, refrigeration.J. Vet. Med. Sci. 72(6): 777-780, 2010 The total number of animals worldwide has decreased in many wildcat species, and various assisted reproductive technologies (ART) are necessary to maintain and increase their numbers. Many studies on ART for endangered feline species are underway using domestic cats as a model [1][2][3][4][5][10][11][12][13][14][15].In a previous study, we collected feline sperm from the cauda epididymis immediately after excision and performed intrauterine insemination of frozen semen (5 10 6 ) [14]. The mean sperm motility following freeze-thawing was 24.0 4.0% (SE), and the conception rate was only 27.3% (3/11). Two female cats delivered five and one kittens, respectively, and another one aborted on 30 days of gestation. This was our initial success rate achieved using epididymal frozen semen in cats. Our previous study is also the only one to report successful conception cases achieved using frozen feline epididymal semen thus far.The duration and temperature of storage before collection of sperm after excision of the epididymis have marked influences on semen qualities in various animal species [6][7][8][9]. In cats, Hay and Goodrowe [5] reported that semen qualities did not differ between sperm collected from the cauda epididymis immediately after excision and after 24-hr storage at 5C. Furthermore, Chatdarong et al. [3] compared the quality of caudal epididymal semen collect from the epididymis after storage for 2 and 4 days at 4C and reported that the sperm motility after storage for 2 days is significantly higher than that after storage for 4 days. Filliers et al. [4] observed that the qualities of semen from the feline epididymis stored in sterile physiological saline for 24 hr at 5C were good. However, Chatdarong et al. [3] and Filliers et al. [4] did not observe the semen quality immediately after excision. Tittarelli et al. [13] also stored the feline epididymis in sterile physiological saline or egg yolk-Tris for 24, 48 and 72 hr and observed the semen qualities. Sperm motility was apparently decreased at all storage time points, and egg yolk-Tris was suggested to be superior as a storage medium compared with physiological saline. Howev...
ABSTRACT. It has been shown that addition of the surfactant Orvus ES paste (OEP) and its main component sodium lauryl sulfate (SLS) to boar or dog semen before freezing improves post-thaw sperm motility and protects acrosome caps. In this study, we investigated the usefulness of the addition of OEP (0, 1, 2 and 4%) or SLS (0, 1, 2, 3 and 4 mg/ml) to cat ejaculates before freezing and their concentrations. Among the OEP addition groups, the 1% OEP group showed higher sperm motility than the other groups. Among the SLS addition groups, the 3 mg/ml SLS group showed slightly higher sperm motility and viability than the other groups. Comparison between the 1% OEP and 3 mg/ml SLS addition groups suggested a higher percentage of sperm with an acrosome cap in the 1% OEP group. The other sperm properties did not significantly differ between the 2 groups. These results indicate that addition of 1% OEP or 3 mg/ ml SLS is effective for freezing of cat ejaculated semen.KEY WORDS: acrosome cap, cat, frozen semen, orvus es paste, sodium lauryl sulfate.J. Vet. Med. Sci. 72(1): 23-27, 2010 In regard to artificial insemination (AI) with frozen feline semen, intravaginal [6,11,19] and intrauterine [6,18,19] inseminations with ejaculates have each been reported in three studies, and intravaginal [20] and intrauterine [15,20] inseminations with epididymal sperm have each been reported in one and two studies, respectively. In our 2003 year study using epididymal sperm [15], we added 7% (v/v) glycerol and 1% Orvus ES paste (OEP, also known as Equex STM paste, Nova Chemical Sales, Inc., Scituate, MA, U.S.A.) to semen as cryoprotective agents and achieved a conception rate of 27.3%. However, we did not evaluate the usefulness of addition of OEP for cryopreservation of feline semen or its optimal concentration. Addition of OEP along with glycerol for the cryopreservation of boar [12] and dog [16,17] semen has been shown to protect the acrosome caps of sperm, thereby increasing and maintaining post-thaw sperm motility for a long period of time. In 2004, Axnér et al. [5] investigated the usefulness of Equex STM paste for cryopreservation of feline epididymal sperm and showed that addition 0.5% (v/v) Equex STM paste led to greater protection of the acrosome caps of sperm after freeze-thawing than no addition, but sperm motility was lower (sperm survival was shorter) 4-6 hr after thawing than in the case of no addition. Our search of the literature revealed no studies in which addition of OEP for semen cryopreservation adversely affected post-thaw sperm motility. It remains unclear whether the results of the study by Axnér et al. [5] regarding cryopreservation of epididymal sperm apply to cryopreservation of cat ejaculates.OEP is known to contain mainly sodium lauryl sulfate (SLS), but data on its concentration and the remaining constituents have not been published. It has been suggested that the effect of SLS might be exerted by modifying the structure of egg yolk lipoproteins in the extracellular medium [4]. Kato et al. [9] employed ...
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