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Accessory reproductive fluids and organs in male domestic birds

Published online by Cambridge University Press:  18 September 2007

Noboru Fujihara
Affiliation:
Department of Animal Science, Kyushu University 46-06 Hakozaki, Fukuoka 812, Japan
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Abstract

Accessory reproductive fluids and organs of male domestic fowl, turkeys, ducks, quail, guinea fowl and pigeons were examined. Male domestic fowl, turkeys and ducks produced different quantities of accessory reproductive fluids – lymph-like fluid and/or foam – during natural copulation. Quail released a unique foam, which is produced constantly in the cloacal region regardless of the ejection of semen and the time of day. The natural ejaculate of this species is always associated with the release of foam. In contrast, guinea fowl and pigeons released neither lymph-like fluid nor foam at ejaculation when semen was collected using the lumbar massage method. The tissues and organs which are involved in the production of these accessory reproductive fluids are the paracloacal vascular body (PVB), lymphatic folds (LF), dorsal proctodeal glands (DPG), ejaculatory groove region (EGR) and tissues in the vicinity of the papilla of the ductus deferens (TVP). Guinea fowl possessed the PVB, DPG and TVP even though they produce no accessory reproductive fluids. The only exception was the pigeon which has neither the tissues nor the organs listed above. The accessory reproductive fluids have a favourable effect on the function of freshly ejaculated spermatozoa in domestic birds.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1992

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References

Amano, T. and Watanabe, S. (1966) Studies on the artificial insemination in Japanese quail. 1. On a method of semen collection and evaluation of semen. Journal of Agricultural Science 12: 5962Google Scholar
Ashizawa, K. and Okauchi, K. (1984) Stimulation of sperm motility and oxygen consumption of fowl spermatozoa by a low molecular weight fraction of seminal plasma. Journal of Reproduction and Fertility 71: 593598CrossRefGoogle ScholarPubMed
Bakst, M.R. and Cecil, H.C. (1981) Changes in the characteristics of turkey ejaculated semen and ductus deferens semen with repeated ejaculations. Reproduction, Nutrition and Development 21: 10951103CrossRefGoogle ScholarPubMed
Bakst, M.R. and Cecil, H.C. (1983) Gross appearance of turkey cloacae before and after single or multiple manual semen collections. Poultry Science 62: 683689CrossRefGoogle ScholarPubMed
Bakst, M.R. and Cecil, H.C. (1985) A microscopic examination of the male turkey proctodeal gland. Journal of Morphology 186: 361368CrossRefGoogle Scholar
Belshaw, R.H.H. (1985) Guinea Fowl of the World. Nimrod Book Services, EnglandGoogle Scholar
von Rautenfeld, Berens D., Burdras, K.-D. and Gassman, R. (1976) A morphological study of antibody transport in the transparent fluid flowing from the lymph-folds of the copulatory organ into the cloacal lumen of the cock (Gallus domesticus). Zeitschrift fur Mikroskopische Anatomischer Forschung 90: 9891008Google ScholarPubMed
Cecil, H.C. and Bakst, M.R. (1985) Volume, sperm concentration, and fertilizing capacity of turkey ejaculates obtained from successive cloacal strokes during semen collection. Poultry Science 64: 12191222CrossRefGoogle ScholarPubMed
Cheng, K.M., Hickman, A.R. and McIntyre, R.F. (1985) Function of foam from the proctodeal gland of the male Japanese quail. Poultry Science 64(Supplement): 78Google Scholar
Cheng, K.M., Hickman, A.R. and Nichols, C.R. (1989a) Role of the proctodeal gland foam of male Japanese quail in natural copulations. Auk 106: 279285Google Scholar
Cheng, K.M., McIntyre, R.F. and Hickman, A.R. (1989b) Proctodeal gland foam enhances competitive fertilization in domestic Japanese quail. Auk 106: 286291Google Scholar
Cherms, F.L. (1968) Variations in semen quality and the relationship of semen quality to fertility in turkeys. Poultry Science 47: 746754CrossRefGoogle ScholarPubMed
Clavert, A., Gabriel-Robez, O. and Montagnon, D. (1985) Physiological role of the seminal vesicle. Progress of Reproductive Biology and Medicine 12: 8094Google Scholar
Coil, W.H. and Wetherbee, D.K. (1959) Observations on the cloacal gland of the Eurasian quail, Coturnix coturnix. Ohio Journal of Science 59: 268270Google Scholar
Fewlass, T.A., Sexton, T.J. and Shaffner, C.S. (1975) Effect of various levels of egg yolk, milk, seminal plasma or blood serum on the respiration and reproductive efficiency of chicken spermatozoa. Poultry Science 54: 346349CrossRefGoogle ScholarPubMed
Fujihara, N. (1990a) Structures and functions of the accessory reproductive organs in the domestic birds. In: Biomechanism of the Gonads (Eds Iwasawa, H. and Ishida, K.), IPC, Tokyo, pp. 5671Google Scholar
Fujihara, N. (1990b) Comparative physiology of avian semen and spermatozoa. Proceedings of Beijing International Symposium on Reproductive Biology,Beijing, p. 41Google Scholar
Fujihara, M. and Koga, O. (1990) Observations on the dorsal proctodeum of the cloacae of male ducks (Anas platyrhnychos). Proceedings of the Fourth Conference of WPSA Far East and South Pacific Federation,Taiwan, p. 36Google Scholar
Fujihara, N. and Koga, O. (1991) The accessory reproductive fluids in the domestic male birds. Journal of Cellular Biochemistry 15E(Supplement): 203Google Scholar
Fujihara, N. and Koga, O. (1992) Morphological characteristics of the dorsal proctodeum of male mallards (Anas platyrhynchos). Zoologische Jahrbücher 2: (In press)Google Scholar
Fujihara, N. and Nishiyama, H. (1976a) Studies on the accessory reproductive organs in the drakes. 3. Ejection mechanism of the fluid from the ejaculatory groove region. Poultry Science 55: 10261030CrossRefGoogle ScholarPubMed
Fujihara, N. and Nishiyama, H. (1976b) Studies on the accessory reproductive organs in the drakes. 4. Effects of androgen on the ejaculatory groove region of the drakes. Poultry Science 55: 13241330CrossRefGoogle Scholar
Fujihara, N. and Nishiyama, H. (1976c) Studies on the accessory reproductive organs in the drakes. 5. Effects of the fluid from the ejaculatory groove region on the spermatozoa of the drake. Poultry Science 55: 24152420CrossRefGoogle Scholar
Fujihara, N. and Nishiyama, H. (1984) Addition to semen of a fluid derived from the cloacal region by male turkeys. Poultry Science 63: 554557CrossRefGoogle ScholarPubMed
Fujihara, N., Nishiyama, H. and Nakashima, N. (1976) Studies on the accessory reproductive organs in the drakes. 2. Macroscopic and microscopic observations of the ejaculatory groove region of the drake. Poultry Science 55: 927935CrossRefGoogle Scholar
Fujihara, N., Nishiyama, H. and Koga, O. (1985a) The mechanism of the ejection of a frothy fluid from the cloaca in the male turkey. Poultry Science 64: 13771381CrossRefGoogle ScholarPubMed
Fujihara, N., Nishiyama, H. and Koga, O. (1985b) The ejection of a frothy fluid from the cloaca region of rooster during manual semen collection. Canadian Journal of Animal Science 65: 985988CrossRefGoogle Scholar
Fujihara, N., Nishiyama, H. and Koga, O. (1985c) Studies on the accessory reproductive organs in the male turkey. Proceedings of 3rd AAAP Animal Science Congress, Seoul 1: 393395Google Scholar
Fujihara, N., Nishiyama, H. and Koga, O. (1986a) Characteristics of artificially ejaculated and ductus deferens semen in the guinea-fowl. Animal Reproduction Science 12: 6974CrossRefGoogle Scholar
Fujihara, N., Nishiyama, H. and Koga, O. (1986b) Localization of frothy fluid-producing region inthe cloaca of male turkeys. Anatomischer Anzeiger Jena 162: 359366Google Scholar
Fujihara, N., Nishiyama, H. and Koga, O. (1986c) The ejection of transparent fluid into the vagina of the hen. Japanese Poultry Science 23: 101103CrossRefGoogle Scholar
Fujihara, N., Nishiyama, H. and Koga, O. (1987) Effect on turkey spermatozoa of a frothy fluid derived from the cloaca of a male turkey. Theriogenology 28: 225235CrossRefGoogle ScholarPubMed
Fujihara, N., Nishiyama, H. and Koga, O. (1988) Anatomical features of cloacal region of male guinea fowl with special reference to the ejection of lymph-like fluid. Anatomischer Anzeiger Jena 167: 341347Google Scholar
Fujihara, N., Nishiyama, H. and Koga, O. (1989a) Physiological characteristics of quail (Coturnix coturnix japonica) spermatozoa. International Conference of Andrology, Florence, 4549Google Scholar
Fujihara, N., Nishiyama, H. and Koga, O. (1989b) Physiological characteristics of semen and spermatozoa in the Japanese quail. Japanese Poultry Science 26: 379380Google Scholar
Fujihara, N., Nishiyama, H. and Koga, O. (1989c) In vitro viability and fertilizing capacity of guinea fowl spermatozoa. Zoological Science 6: 731739Google Scholar
Fujihara, N., Nishiyama, H. and Koga, O. (1989d) Physiological characteristics of semen and spermatozoa in the domestic pigeons (Columba livia domestica). Zoological Science 6: 1164Google Scholar
Fujihara, N., Koga, O. and Nishiyama, H. (1990a) Physiological characteristics of pigeon semen and spermatozoa. Japanese Poultry Science 27: 228Google Scholar
Fujihara, N., Nishiyama, H. and Koga, O. (1990b) Physiological characteristics of semen and spermatozoa in the domestic birds. Proceedings of 5th AAAP Animal Science Congress, Taiwan 3: 306Google Scholar
Fujihara, N., Ando, K., and Koga, O. (1990c) Innervation of the paracloacal vascular body in the fowl and quail. Japanese Poultry Science 26: 432433Google Scholar
Fujii, S. and Tamura, T. (1967) Studies on the cloacal gland of the quail. II. Histochemical observations on secretions in the gland. Japanese Poultry Science 4: 194200CrossRefGoogle Scholar
Gassmann, R. and von Rautenfeld, Berens D. (1977) Detection of antibody in transparent fluid of semen and in serum after inoculation of newcastle disease vaccines by different routes. Avian Pathology 6: 235240CrossRefGoogle ScholarPubMed
Guzsal, E. (1974) Erection apparatus of the copulatory organ of ganders and drakes. Acta Veterinaria Academiae Scientiarum Hungaricae 24: 361373Google ScholarPubMed
Hess, R.A., Thurston, R.J. and Biellier, H.V. (1976) Morphology of the epididymal region and ductus deferens of the turkey (Meleagris gallopavo). Journal of Anatomy 122: 241252Google ScholarPubMed
Homma, K. (1969) Japanese quail in biological research – a review. Japanese Poultry Science 7: 157165CrossRefGoogle Scholar
Ikeda, K. and Taji, K. (1954) On the foamy ejaculate of Japanese quail, Coturnix coturnix japonica. Scientific Reports of the Matsuyama Agricultural College 13: 14Google Scholar
Kamar, G.A.R. (1958) The collection of cock's semen without milking the copulatory organ. Poultry Science 37: 13821385CrossRefGoogle Scholar
Kamar, G.A.R. (1962) Semen characteristics of various breeds of drakes in the subtropics. Journal of Reproduction and Fertility 3: 405409CrossRefGoogle ScholarPubMed
Kichev, G. and Danov, D. (1972) Microelectrophoretic study on cellogel of protein, glyco- and lipoproteins in the seminal plasma and blood of the cock. Proceedings of 7th International Congress on Animal Reproduction and A.I.,München, pp. 2275–2279Google Scholar
King, A.S. (1979) Systema urogenitale. In: Nomina Anatomica Avium (Ed. Baumel, J.J.), Academic Press, London, pp. 289335Google Scholar
King, A.S. (1981a) Cloaca. In: Form and Function in Birds, Volume 2 (Eds King, A.S. and McLelland, J.), Academic Press, London, pp. 63105Google Scholar
King, A.S. (1981b) Phallus: In: Form and Function in Birds, Volume 2 (Eds. King, A.S. and McLelland, J.), Academic Press, London, pp. 107147Google Scholar
Klemm, R.D., Knight, C.E. and Stein, S. (1973) Gross and microscopic morphology of the glandula proctodealis (foam gland) of Coturnix c. japonica (Aves). Journal of Morphology 141: 171184CrossRefGoogle ScholarPubMed
Knight, C.E. (1970) The anatomy of the structures involved in the erection-dilution mechanism in the male domestic fowl. PhD Thesis, Michigan State UniversityGoogle Scholar
Knight, C.E. and Klemm, R.D. (1972) Anatomy of the foamy glands in the Coturnix coturnix japonica. Poultry Science 51: 1925Google Scholar
Kobayashi, S., Okamoto, S. and Matsuo, T. (1972) The influence of the foamy materials on the fertilizing capacity of semen in the Japanese quail, Coturnix coturnix japonica. Agricultural Bulletin of Sage University 32: 8995Google Scholar
Komárek, V. (1970) The cloaca of the turkey-cock and of the cock. Acta Veterinaria Brno 40: 1322Google Scholar
Lake, P.E. (1956) A retarding factor in the problem of fowl semen storage. Proceedings of 3rd International Congress on Animal Reproduction, Cambridge 3: 104106Google Scholar
Lake, P.E. (1957a) The male reproductive tract of the fowl. Journal of Anatomy 91: 116129Google ScholarPubMed
Lake, P.E. (1957b) Fowl semen collected by the massage method. Journal of Agricultural Science 49: 120126CrossRefGoogle Scholar
Lake, P.E. (1966) Physiology and biochemistry of poultry semen. In: Advances in Reproductive Physiology (Ed. McLaren, A), Logos Press, London, pp 93123Google Scholar
Lake, P.E. (1971) The male in reproduction. In: Physiology and Biochemistry of the Domestic Fowl, Volume 3 (Eds Bell, D.J. and Freeman, B.M.), Academic Press, London, pp. 14111447Google Scholar
Lake, P.E. (1981) Male genital organs. In: Form and Function in Birds, Volume 2 (Eds King, A.S. and McLelland, J.), Academic Press, London, pp. 161Google Scholar
Lake, P.E. (1989) Recent research in male reproduction. In: Recent Advances in Turkey Science (Eds Nixey, C. and Grey, T.C.), Butterworths, London, pp. 5567Google Scholar
Lake, P.E. and El Jack, M.H. (1964) Further observations on the chemical composition of the seminal plasma of the domestic cock. Proceedings of the 5th International Congress of Animal Reproduction and A.I., Trento 2: 359363Google Scholar
Lake, P.E. and Wishart, G.J. (1984) Comparative physiology of turkey and fowl semen. In: Reproductive Biology of Poultry (Eds Cunningham, F.J., Lake, P.E. and Hewitt, D.), Longman, Harlow, pp. 151160Google Scholar
Lake, P.E., Ravie, O. and Waddington, D. (1985) Some effects of the composition of inseminated semen and the site of its deposition on fertility in Gallus domesticus. Animal Reproduction Science 9: 273284CrossRefGoogle Scholar
Leslie, G.A., Wilson, H.R. and Clem, L.W. (1971) Studies on the secretory immunologic system of fowl. 1. Presence of immunoglobulins in chicken secretions. Journal of Immunology 106: 14411446CrossRefGoogle Scholar
Mann, T. and Lutwak-Mann, C. (1981) Male Reproductive Function and Semen, Springer-Verlag, BerlinCrossRefGoogle Scholar
McFarland, L.Z., Warner, R.L., Wilson, W.O. and Mather, F.B. (1968) The cloacal gland complex of the Japanese quail. Experientia 15: 941943CrossRefGoogle Scholar
Nalbandov, A.V. (1976) Reproductive Physiology of Mammals and Birds, 3rd edn, Freeman, San FranciscoGoogle Scholar
Nishida, T. (1964) Comparative and topographical anatomy of the fowl. XLII. Blood vascular system of the male reproductive organs. Japanese Journal of Veterinary Research 26: 211221Google ScholarPubMed
Nishida, T., Sasaki, H. and Mochizuki, T. (1983) Lymphatic pathway in the epithelium of the male copulatory organ in the guinea fowl. Proceedings of the 5th World Conference on Animal Production, Tokyo 2: 283285Google Scholar
Nishida, T., Osawa, K., Kuromaru, M. and Hayashi, Y. (1988) Morphological studies on the copulatory organ of the pigeon. Abstracts of 80th Annual Meeting of Japanese Society of Zootechnical Science, p. 107Google Scholar
Nishiyama, H. (1951) Studies on the physiology of reproduction in the male fowl. III. On the addition of transparent fluid to the cock's semen. Science Bulletin of the Faculty of Agriculture, Kyushu University 13: 377387Google Scholar
Nishiyama, H. (1954) On the characteristics of the transparent fluid. 1. Origin of transparent fluid studied with aid of 32P. Japanese Journal of Zootechnical Science 25: 102104Google Scholar
Nishiyama, H. (1955) Studies on the accessory reproductive organs in the cock. Journal of the Faculty of Agriculture, Kyushu University 10: 277305CrossRefGoogle Scholar
Nishiyama, H. (1957) On the characteristics of the transparent fluid. II. An electrophoretic study of proteins of the transparent fluid. Journal of the Faculty of Agriculture, Kyushu University 11: 6368CrossRefGoogle Scholar
Nishiyama, H. (1961) On the quality and quantity of the cock semen obtained by different collection methods. Memoirs of the Faculty of Agriculture, Kagoshima University 4: 4350Google Scholar
Nishiyama, H. (1978) Male reproductive organs, semen and fertilization in the domestic fowl – a review. Japanese Poultry Science 15: 111CrossRefGoogle Scholar
Nishiyama, H. (1979) Fertilization mechanism and artificial insemination in the domestic fowl. Japanese Poultry Science (special issue for 25th anniversary): 19–25Google Scholar
Nishiyama, H. and Fujishima, T. (1961) On the ejection of the accessory reproductive fluid of the cock during natural copulation. Memoirs of the Faculty of Agriculture, Kagoshima University 4: 2742Google Scholar
Nishiyama, H. and Fujishima, T. (1963) On the hydrogen ion concentration of blood, blood plasma and blood serum of the cock. Bulletin of Faculty of Agriculture, Kagoshima University 13: 162172Google Scholar
Nishiyama, H. and Ogawa, K. (1961) On the function of the vascular body, an accessory reproductive organ, of the cock. Japanese Journal of Zootechnical Science 32: 8998Google Scholar
Nishiyama, H., Ogawa, K. and Nakanishi, Y. (1971) Studies on the artificial insemination in the domestic fowl. III. Sperm concentration of semen at collection and sperm-quality of the semen. Memoirs of the Faculty of Agriculture, Kagoshima University 8: 355366Google Scholar
Nishiyama, H., Nakashima, N. and Fujihara, N. (1976) Studies on the accessory reproductive organs in the drake. 1. Addition to the semen of a fluid derived from the ejaculatory groove region of the drake. Poultry Science 55: 234242CrossRefGoogle Scholar
Nwakalor, L.N., Okeke, G.C. and Njoku, D.C. (1988) Semen characteristics of the guinea fowl. Theriogenology 29: 545554CrossRefGoogle ScholarPubMed
Ogawa, K., Nakanishi, Y., Tojo, H. and Imanishi, M. (1974) Effect of frothy fluid from cloacal gland on fertility in the Japanese quail (Coturnix coturnix japonica). Bulletin of Faculty of Agriculture, Kagoshima University 24: 3540Google Scholar
Owen, R.D. (1941) Artificial insemination of pigeons and doves. Poultry Science 20: 428431CrossRefGoogle Scholar
Parker, J.E., McKenzie, F.F. and Kempster, H.L. (1942) Fertility in the male domestic fowl. Missouri Agricultural Experimental Station, Research Bulletin 347 150Google Scholar
Polakoski, K.L. and Kopta, M. (1982) Seminal plasma. In: Biochemistry of Mammalian Reproduction (Eds Zaneveld, L.J.D. and Chatterton, R.T.), John Wiley and Sons, New York, pp. 89117Google Scholar
Sachs, B.D. (1967) Photoperiodic control of the cloacal gland of the Japanese quail. Science 157: 201203CrossRefGoogle ScholarPubMed
Saeki, Y. (1960) Crooked-necked spermatozoa in relation to low fertility in the artificial insemination of fowl. Poultry Science 39: 13541361CrossRefGoogle Scholar
Saeki, Y. and Brown, K.I. (1962) Fertilizing ability and laboratory evaluation of ejaculated and vasa deferentia semen in turkeys. Poultry Science 41: 905909CrossRefGoogle Scholar
Schindler, H. and Scharf, S. (1963) The distribution of sugars, lactic acid and glutamic acid in the genital tract and body fluids of the domestic cock. Israel Journal of Agricultural Research 13: 163172Google Scholar
Szumowski, P., Theret, M. and Denis, B. (1976) Semen and artificial insemination of pigeons. VIIIth International Congress on Animal Reproduction and Artificial Insemination, Cracow 4: 10861089Google Scholar
Takeda, A. (1959) Studies on the cock semen. 1. Na, K and Ca levels of the seminal plasma. Research Report of Faculty of Textile and Sericulture, Shinshu University 9: 5559Google Scholar
Tamura, T. and Fujii, S. (1967) Studies on the cloacal gland of the quail. I. Macroscopical and microscopical observations. Japanese Poultry Science 4: 187193CrossRefGoogle Scholar
Tan, N.S. (1980) The frequency of collection and semen production in Muscovy ducks. British Poultry Science 21: 265272CrossRefGoogle ScholarPubMed
Terada, T. (1980) Physiological function of avian seminal plasma – a review. Japanese Poultry Science 17: 163174CrossRefGoogle Scholar
Terada, T. and Koga, O. (1971) Antigenicity of sperm and seminal plasma in the fowl. Japanese Poultry Science 8(Supplement): 2122Google Scholar
Terada, T. and Nishiyama, H. (1974) Effect of cock serum on motility, deformity and fertility of ejaculated cock spermatozoa. Japanese Poultry Science 11: 3944CrossRefGoogle Scholar
Terada, T. and Watanabe, M. (1978) Effects of addition of cock blood serum to semen diluents on the motility, glucose utilization and oxygen consumption of cock spermatozoa. Japanese Poultry Science 13: 223228CrossRefGoogle Scholar
Terada, T. and Watanabe, M. (1980) Effect of accessory reproductive organ fluid on freezing cock semen. Japanese Journal of Zootechnical Science 51: 717722Google Scholar
Terada, T., Inoue, A. and Watanabe, M. (1978) Effects of homologous and heterologous fresh blood serum on motility of cock spermatozoa. Japanese Journal of Zootechnical Science 49: 510516Google Scholar
Terada, T., Watanabe, M. and Tsutsumi, Y. (1984) Possible significance of accessory reproductive fluid in exhibition of fertilizing ability of spermatozoa in the domestic fowl, Gallus domesticus. Japanese Journal of Zootechnical Science 55: 5258Google Scholar
Thurston, R.J., Hess, R.A. and Froman, D.P. (1982a) Elevated seminal plasma protein: a characteristic of yellow turkey semen. Poultry Science 61: 19051911CrossRefGoogle ScholarPubMed
Thurston, R.J., Hess, R.A., Hughes, B.L. and Froman, D.P. (1982b) Seminal plasma free amino acids and seminal and blood plasma proteins of the guinea fowl (Numidia meleagris). Poultry Science 61: 17441747CrossRefGoogle ScholarPubMed
Van Krey, H.P. (1990) Reproductive biology in relation to breeding and genetics. In: Poultry Breeding and Genetics (Ed. Crewford, R.D.), Elsevier, Amsterdam, pp. 6190Google Scholar
Watanabe, M. (1965) Artificial insemination of poultry. Japanese Journal of Zootechnical Science 36: 2939Google Scholar
Watson, P.F. (1990) Artificial insemination and the preservation of semen. In: Marshall's Physiology of Reproduction, 4th edn, Volume 2. Reproduction in Male (Ed. Lamming, G.E.), Churchill Livingstone, London, pp. 747869Google Scholar
Yamane, J., Tsukunaga, S. and Takahashi, T. (1966) ‘Hiroshima’ method of artificial insemination of the domestic fowl. Journal of the Faculty of Fisheries and Animal Husbandry, Hiroshima University 6: 395429Google Scholar
Yamano, S. (1984) Localization of two types of nerve ending in the corpus vasculare paracloacale of the cock. Japanese Journal of Veterinary Science 46: 229231Google ScholarPubMed