Male Reproduction - Donkey
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Male Reproductive Anatomical peculiarities
Breeding evaluation and semen quality
Evaluation of breeding soundness is performed similarly to the stallion. Testicular size, semen volume and total sperm per ejaculate in the jack are significantly higher than in stallions (Tibary et al, 2005). Testicular ultrasonography is characterized by a large central vein and more prominent caput and cauda epididymis. Ultrasonographic evaluation of the accessory sex glands is similar to that of the stallion.
Semen can be collected relatively easily using an artificial vagina (Kadir, 1980; Glatzel et al, 1981). Ex-copula semen collection using imipramine/xylazine has been attempted with very limited success rate (Sghiri et al, 2006).
Semen volume collected by an artificial vagina ranges from 25 to 50ml in miniature donkeys (Purdy, 2005b), from 12.5 to 40 ml in small breeds such as the north African donkey and from 25 to 250 ml in large breeds. In some breeds (Catalonian, Poitou) the gel fraction may be very copious. Very high volumes (115 ml) have also been reported in miniature donkeys (Purdy, 2005b).
Spermatogenic efficiency increases until six years of age, then plateaus (Nipken and Wrobel, 1997; Tibary et al, 2005). The total number of spermatozoa in the ejaculate ranges from 5 to 18 billion. Total progressive motility and normal morphology are generally above 70% in normal healthy males. As in the horse, abaxial attachment of the tail is normal. Sperm abnormalities are similar to those described in horses (Miro et al, 2005; Purdy, 2005b; Tibary et al, 2005). Objective evaluation of donkey sperm motion parameters using computer-assisted motility analysis has been described (Miro et al, 2005; Tibary et al, 2005).
The effect of season (photoperiod and ambient temperature) on semen production, semen quality and libido has been investigated. Semen production and quality are higher during the peak of the breeding season but in most studies seasonal effects on these parameters are not very marked (Glatzel et al, 1981; Roy et al, 2003, 2004; Tibary et al, 2005).
References
- Tibary, A., Sghiri, A. & Bakkoury, M. (2008) Reproduction In Svendsen, E.D., Duncan, J. and Hadrill, D. (2008) The Professional Handbook of the Donkey, 4th edition, Whittet Books, Chapter 17
- Carluccio, A., Villani, M., Contri, A., Tosi, U., and Battocchio, M. (2004). ‘Preliminary study on some seminal and testicular morphometric characteristics in Martina Franca jackass’. Ippologia 15. pp 23-26.
- Gastal, M.O., Henry, M., Beker, A.R., Gastal, E.L., and Goncalves, A. (1996). ‘Sexual behavior of donkey jacks: influence of ejaculatory frequency and season’. Theriogenology 46. pp 593-603.
- Glatzel, P., Kadir, E., and Tibary, A. (1981). ‘Pferde- und Eselhenge der marokkanischen Landespferde- un Maultierzucht. Erste Ergebnisse aus dem Einsatz von Flussig- un Gefriersamen fur die Maultierproduktion’. Berl Munch Tierarztl Wochenschr 94. pp 445-448.
- Henry, M. (2001). ‘Some reproductive characteristics of donkeys’. Pratique Vétérinaire Equine 33. pp 11-20.
- Henry, M., McDonnell, S.M., Lodi, L.D., and Gastal, E.L. (1991). ‘Pasture mating behaviour of donkeys Equus asinus at natural and induced estrus’. J. Reprod. Fertil. Suppl 44. pp 77–86.
- Henry, M., Lodi, L.D., and Gastal, M.M.F.O. (1998). ‘Sexual behaviour of domesticated donkeys (Equus asinus) breeding under controlled or free range management systems’. Applied Animal Behaviour Science 60. pp 263-276.
- Kadir, H. (1980). ‘Production mulassière par le biais de l’insémination artificielle au Maroc’. Thèse de Doctorat Vétérinaire, Institut Agronomique et Vétérinaire Hassan II.
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- Lodi, L.D., Henry, M., Paranhos, D.A., and Costa, M.J.R. (1994). ‘Behavior of donkeys (Equus asinus) breeding mares (Equus caballus) at pasture’. Biol. Repro. Mono 1. pp 591-598.
- McDonnell, S.M. (1998). ‘Reproductive behavior of donkeys (Equus asinus)’. Applied Animal Behaviour Science 60. pp 277-282.
- Miro, J., Lobo, V. , Quitero-Moreno, A., Medrano, A., Pena, A., and Rigaua, T. (2005). ‘ Sperm motility patterns and metabolism in Catalonian donkey semen’. Theriogenology 63. pp 1706-1716.
- Nipken, C., Wrobel, K.J. (1997). ‘A quantitative morphological study of age-related changes in the donkey testis in the period between puberty and senium’. Andrologia 29. pp 149-161.
- Purdy, S.R. (2005b). ‘Ultrasound examination of the female miniature donkey reproductive tract’. in: Veterinary Care of Donkeys. N.S. Matthews and T.S. Taylor (eds). International Veterinary information Service, Ithaca NY (www.ivis.org), last updated: 11 May 2005; A2925.0505.
- Roy, A.K., Yadav, M.P. , and Sengar, O.P.S. (2003). ‘Effect of season on the physical characteristics of donkey (Equus asinus) semen’. Indian J. Anim. Sci. 73. pp 620-622.
- Sghiri, A., Tibary, A., El Idrissi, R. (2006). ‘Behavioral response to imipramine/xylazine treatment in jackass’. Proceedings 9th World Equine Veterinary Congress, Marrakech, In Press.
- Tibary, A. (2005). ‘Pathologie génitale/Infertilité’. Reproduction Equine Tome II: L’Etalon. Tibary, A., and Bakkoury, M. (eds), Actes Editions, IAV Hassan II, Maroc, 2005. pp 185-356.
- Tibary, A. (2006). ‘Normal and abnormal behavior in the male equine’. Current Therapy in Equine Reproduction, J.C. Samper, A. McKinnon and J. Pycock (eds). Saunders, in Press.
- Tibary, A., Bakkoury, M., Anouassi, A., and Sghiri, A. (2005). ‘Examen et évaluation de l’aptitude à la reproduction’. Reproduction Equine Tome II: L’ Etalon. A. Tibary, M. Bakkoury (eds). Actes Editions, IAV Hassan II, Maroc, 2005. pp 167-174.
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