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Reproductive Disorders - Donkey (view source)
Revision as of 20:15, 19 February 2010
, 20:15, 19 February 2010no edit summary
There are very few recent studies on the overall fertility of the asinine population. High pregnancy and foaling rates are often observed in feral donkeys when pasture conditions are optimal.
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'''[[Venereal Diseases - Donkey|Venereal Diseases]]
'''[[Male Reproductive Disorders - Donkey|Male Reproductive Disorders]]
'''[[Female Reproductive Disorders - Donkey|Female Reproductive Disorders]]
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As in the horse, the most important venereal diseases are [[Donkey - Equine Viral Arteritis|'''equine viral arteritis, EVA''']] (Ramina ''et al'', 1999), [[Taylorella equigenitalis|'''contagious equine metritis, CEM''']] (Matsuda and Moore, 2003), and [[Donkey - Trypanosomosis|'''dourine''']] (Turnbull ''et al'', 2002). Infections with [[Pseudomonas aeruginosa and Burkholderia species|''Pseudomonas aeruginosa'']] and [[Klebsiella|''Klebsiella pneumoniae'']] have also been suspected as possible causes of poor reproductive performances due to venereal transmission.
The asinine strain of '''equine arteritis virus (EAV)''' has been shown to behave similarly to the horse strain (Paweska ''et al'', 1996; Ramina ''et al'', 1999). The South African strain of EAV appears to be poorly transmissible to horses (Paweska ''et al'', 1996; Paweska ''et al'', 1997).
'''CEM organisms''' isolated from donkeys are different from [[Taylorella equigenitalis|''Taylorella equigenitalis'']] and a new nomenclature for the organism has been proposed, that is, ''T. asinigenitalis'' (Jang ''et al'', 2001; Matsuda and Moore, 2003). These ‘atypical’ donkey ''Taylorella'' have been shown to cause the same syndrome as CEM in mares and remain in the urethral fossa for as long as 111 days
(Katz ''et al'', 2000).
==Reproductive disorders in the male==
Most conditions affecting horses can be found in donkeys and the diagnostic approach to infertility is similar to that used in stallions (Tibary, 2005). <u>Testicular descent may be delayed until two or three years of age.</u> In donkeys, the authors (Tibary, A., Sghiri, A. & Bakkoury, M.) have seen several cases of '''cryptorchidism, haemospermia '''and '''ejaculation failure'''.
'''Oestrone sulphate levels are not a good indicator of the presence of testicular tissue and CANNOT be used to differentiate between cryptorchid males and geldings displaying male behaviour''' (Arrighi and Bosu, 1989). A standard technique for the diagnosis of cryptorchidism is to determine testosterone levels before and at 2 hours and 24 hours after intravenous administration of human chorionic gonadotrophin (6,000-10,000 IUhCG). <u>Males with testicular tissue should have a circulating testosterone level greater than 100 pg/ml or should register at least a twofold increase in testosterone concentration after hCG challenge.</u>
[[Donkey - Castration|'''Castration''']] tends to result in a higher incidence of [[Donkey - Castration#Complications of castration|haemorrhage complications]]. This is not the case for mules. '''Ectopic testicles''' (Ragab and Mostafa, 1993), '''interstitial cell tumours '''(Panebianco, 1960) and '''infectious epididymitis '''(Schebitz and Hansen, 1959) have been
reported. In the authors’ (Tibary, A., Sghiri, A. & Bakkoury, M.) experience, '''testicular degeneration''' is common and may be due to nutritional causes and heavy parasitism. '''Orchitis''' may be caused by [[Donkey - Strongyles|strongyle ''larva migrans'']].
==Reproductive disorders in the female==
Fertility in jennies seems to be higher than in mares. Inbreeding may be an important factor of poor fertility in some isolated herds (Kadir, 1980; Darre ''et al'', 1998). Reported anomalies of reproduction in jennies include '''persistent corpus luteum, ovarian teratomas, granulosa cell tumours''' (Norris ''et al'', 1968), '''uterine infection''' and '''uterine fibrosis'''. Pyometra may be a consequence of severe dystocia.
Donkeys are prone to [[Donkey - Hyperlipaemia|hyperlipaemia]] and hepatic lipidosis during pregnancy, often complicated by hepato-encephalopathy, hypocalcaemia, azotaemia, hyponatraemia, hypochloraemia and acidosis (Tarrant ''et al'', 1998). '''Retained placenta and hypocalcaemia''' may be seen in stressed animals.
'''Abortion''' has been cited as a major problem in working equines (Pearson ''et al'', 2003). Infectious causes of abortion in donkeys are similar to those reported in horses, the most commonly reported being [[Equine Herpesvirus 1|EHV-1]] (Tewari ''et al'', 1994), ''Leptospira'' (Arora and Baxi, 1978), [[Streptococci|''Streptococcus equi zooepidemicus'']] (Giorgi ''et al'', 1984) and [[Salmonella|''Salmonella spp.'']] (Hofer ''et al'', 2004). Non-infectious abortion due to foetal abnormalities has been described in miniature donkeys (Miller, 1989). Twinning is a cause of non-infectious abortion in some breeds.
==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
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[[Category:Donkey]]
[[Category:Donkey]]
[[Category:Reproduction]]
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[[Category:Donkey]][[Category:Reproduction]]