ABSTRACT. Using the triple-stain technique, we investigated whether sperm acrosomes in frozen canine semen were protected during freezing and thawing by addition of a surfactant, Orvus ES Paste (OEP), to the extender. Acrosomes were clearly shown to be protected by the addition of OEP to the entender when compared with those in sperm frozen without OEP addition (p<0.05).-KEY WORDS: acrosome, canine, Orvus ES Paste.A high percentage of boar sperm are damaged by freezing. Graham et al. [1] demonstrated that adding a surfactant, Orvus ES Paste (OEP), to the extender protects acrosomes, making frozen boar semen available for practical use. By electron microscopy, Toyama and Itoh [7] showed that acrosomes are maintained in a normal state by adding OEP to the extender used to freeze boar semen. Kato et al.[2] obtained a similar result using sodium laurylsulfate (1.2-1.6 mg/ml, SLS), which is the major ingredient of OEP.Similar to boar sperm, canine sperm has a low resistance to freezing, and no practical procedure for use of frozen semen has been developed yet. In 1993, Nöthling and Volkmann [3] initially added 0.5% OEP to frozen canine semen. However, they did not discuss the effectiveness of adding OEP to frozen canine semen. Later in 1997 and 1999, Rota et al. [4, 5] reported that adding 0.5% OEP to the extender of frozen canine semen increases its effectiveness. We also investigated various concentrations of OEP added to the extender of frozen canine semen, and their effectiveness. The result showed that addition of 0.5-1.0% OEP improves the sperm motility after thawing and maintains the motility for a prolonged time after thawing [8]. The reason for these effects may be that OEP protects acrosomes, as Toyama and Itoh [7] showed in boar sperm.We therefore, added OEP at a final concentration of 0.75% to Tris-fructose-citrate extender containing 20% (v/ v) egg yolk (EYT-FC), which was used by Rota et al. [4,5] as an extender for frozen canine semen, and investigated whether acrosomes were protected using the triple-stain technique (TST) reported by Talbot and Chacon [6].The five dogs used in the experiments were 2-6 year-old beagles with copulation ability and fertility. The semen samples, collected by digital manipulation, were divided into three fractions. Semen volume, and the number, motility, and viability of sperm of the 2nd fraction were determined by methods previously described [9]. After examination, semen was subjected to the first dilution with EYT-FC, and was then divided into two fractions. In the second dilution, one fraction was diluted with the secondary extender containing OEP, and the other fraction was diluted with the secondary extender without OEP addition. Both primary and secondary dilutions were performed at room temperature (20°C). The final sperm concentration was adjusted to 1 × 10 8 /ml, and 0.5 ml straws were used. The final glycerol concentration was adjusted to 7%. Semen was frozen using a conventional freezer with the freezing temperature conditions and method previously described...
ABSTRACT. The breeding season was investigated in 174 female cats that were acclimated under a natural photoperiod, and determined the interval between birth and initial estrus (puberty) was determined in 125 cats. Although the breeding season differed noticeably among individual animals, the mean was 180.4 ± 3.0 (SE) days between the end of January and the end of July. The interval between birth and first estrus ranged from 181 to 560 days, with a mean of 345.0 ± 0.9 days. With respect to month of birth, the mean interval was 343.0 ± 9.5 days in cats born between March and June. Among cats that were born between July and October, the mean intervals were 242.0 ± 6.3 days in cats that exhibited estrus the year after birth and 519.2 ± 5.8 days in those that exhibited estrus 2 years after birth. KEY WORDS: breeding season, feline, natural photoperiod.J. Vet. Med. Sci. 66(9): 1129-1132, 2004 The domestic cat is a seasonally polyestrous animal. The onset of puberty in female cats occurs at an average age of 8 to 10 months [5,11]. Ovulation and the initial release of LH are usually observed 24 to 30 hr after copulation [15]. It has been reported that the breeding season starts in December to February, and continues until September [2,6,13]. These factors may depend on the day length, that is, latitude [4].The mechanism by which the photoperiod influences the hypothalamus pituitary gland gonadal axis system via melatonin has been clarified in cats [8,9]. In cats, when the photoperiod is shortened, melatonin and PRL secretion are enhanced, reducing ovarian function [1,8,9]. Leyva et al. [9] reported that no recurrent estrus occurred after melatonin was administered to cats under 24-hr lighting. No recurrent estrus occurs under 8-hr lighting in the cat room, whereas estrus recurs under 12-hr lighting [4,8,10,13,14]. Therefore, it is recommended that the lighting cycle should be 14 hr or more for cat breeding [10,12,14]. Nevertheless, no previous study has provided detailed data on the estrus status when cats are acclimated under a natural photoperiod. In this study, we investigated the breeding season in female cats that were acclimated as a group at a constant room temperature under a natural photoperiod. We also investigated the interval required until first estrus (puberty) in female cats that were born under those conditions. Animals: We used 103 female cats ranging in age from 2 to 8 years that were acclimated via passage breeding in our laboratory between 1989 and 2002 (latitude: 35 degrees, 42 min N). In some cats, estrus was investigated for 2 to 6 years. A total of 174 cats were investigated. The cat room was located on the second floor, and measured 4.5 × 3.0 × 2.5 (height) m. The east, west, and south sides were transparent and glass-plated. The east and west glass windows measured 3.6 × 0.9 × 0.9 (height) m. The south glass window measured 1.8 × 0.9 × 0.9 (height) m. Room temperature was 23 ± 2°C. The cats were acclimated as a group. Dry food (Hill's feline maintenance, U.S.A.) and water were given ad libitum...
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 ...
ABSTRACT. Unilateral intrauterine horn insemination (UIUI) was carried out in cats, and we investigated the fertilization rate of ova ovulated from the contralateral ovary. Various numbers of sperm were used to inseminate the uterine horn on the side where ovulati on was inhibited. The rates of conception were 1/11 (9.1%), 2/11 (18.2%), and 5/7 (71.4%) in the 2 × 10 6 , 4 × 10 6 , and 8 × 10 6 groups, respectively. Furthermore, the fertilization rate was 70.7% in the 8 × 10 6 group. Thus, ova ovulated from the contralateral ovary were not fertilized or the fertilization rate was low in some cats even when UIUI was performed with a large number of sperm. KEY WORDS: feline, fertilization rate, unilateral artificial insemination.J. Vet. Med. Sci. 66(9): 1143-1145, 2004 With respect to artificial insemination (AI) in cats, 3 studies each have reported intravaginal insemination (IVI) [4,6,8] and intrauterine horn insemination (IUI) [1,12,13], and one study, tubal insemination [11]. In dogs and cats, the sperm count required for conception when IUI is used is one-tenth of that when IVI is used [8,10,12,14], but IUI must be surgically performed under general anesthesia or with a fiberscope. Concerning IUI, it remains to be clarified whether insemination in the left and right uterine horn is needed to improve the fertilization rate. We previously performed unilateral IUI (UIUI) with various sperm counts in cats [12]. Ova ovulated from the contralateral ovary achieved fertilization in some animals with a low inseminated sperm count. Nevertheless, we could not accurately show the inseminated sperm count or fertilization with ova ovulated from the contralateral ovary, because ovulation occurred in both the left and right ovaries. We also reported that when the number of sperm for UIUI was increased in dogs with a uterine morphology similar to that in cats, fertilization with ova ovulated from the contralateral ovary was frequently achieved [10].In this study, we performed UIUI in cats, and clarified the inseminated sperm count and fertilization with an ovum ovulated on the contralateral side.Animals: We used 20 female cats ranging from 2 to 6 years in age bred at Nippon Veterinary and Animal Science University. Some animals were repeatedly used for the experiment. Nine of these cats underwent unilateral ovariectomy two years ago. Furthermore, we used 4 male cats with coitus capacity and fertility, ranging from 6 to 7 years in age. These cats were acclimated in an animal room at 23 ± 2°C. Female cats were housed as a group in a cat room measuring 4 × 7 m. Furthermore, male cats were individually housed in cages measuring 60 × 90 × 120 (height) cm. Dry food (Hill's feline maintenance, U.S.A.) and water were given ad libitum. Female cats were brought into contact with male cats in the morning and evening everyday, and the presence or absence of estrus was examined.All the animals were maintained according to the guidelines of the Animal Care and Use Committee of the Nippon Veterinary and Animal Science University.Collection o...
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