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Endometritis - Cattle (view source)
Revision as of 15:48, 6 September 2011
, 15:48, 6 September 2011Created page with " ==Introduction== Endometritis is an '''infection of the uterine endometrium''' Cattle endometritis is a '''common''' condition that is known by the layman as ''''whites''''. It..."
==Introduction==
Endometritis is an '''infection of the uterine endometrium'''
Cattle endometritis is a '''common''' condition that is known by the layman as ''''whites''''. It occurs '''three weeks or more''' '''after calving''' and should not be confused with the more severe condition of metritis which occurs immediately post-partum. The main consequence of endometritis is '''poor fertility'''. Therefore it has a '''major economic impact''' by '''increasing calving interval''', '''services per conception''' and '''cull rates''' and by '''decreasing milk yield'''. It is reported to have an incidence of between '''ten and fifteen percent''' in dairy herds (however it is very variable from herd to herd), with the total cost of '''£160 per case'''.
==Aetiology==
The normally '''sterile''' uterus is '''contaminated by environmental microorganisms during parturition''' or '''immediately postpartum'''. The main bacteria involved in endometritis is '''''[[Actinobaccillus pyogenes]]''''', however, numerous [[:Category:Gram Negative Anaerobic Bacteria|'''gram-negative anaerobes''']] may also be involved. The presence of this opportunist bacteria can '''delay return to service''' and '''cyclical activity''', '''prevent fertilisation''' and cause '''early embryonic death''' by producing a hostile uterine environment. It is also reported that it increases incidence of '''ovarian cysts'''.
==Signalment==
Endometritis can occur in any cow post-partum however incidence is increased by the following '''predisposing factors''':
* Retained foetal membranes
* [[Dystocia]]
* Caesarian section or assisted calving
* Induced parturition
* Still Birth
* Twins
* Unhygienic calving environment - includes seasonal effect as indoor calving has higher endometritis rates
* Ovarian inactivity
* Parity
* Concurrent disease and nutrition - [[Fatty Liver Syndrome|fatty liver disease]] and [[Hypocalcaemia|hypocalcaemia]] are reported to increase endometritis rates.
Multiple defense mechanisms exist to prevent opportunistic infection of the uterus. The '''vulva''' and '''cervix''' provide a '''physical barrier''' to opportunist bacteria; '''resident bacteria''' in the vagina '''prevents''' the '''colonisation''' of harmful bacteria; '''involution''' and '''caruncle sloughing''' expel contaminants and tissue debris; a '''higher pH''' during '''oestrus''' prevent bacterial growth and various '''immunological mechanisms''' also act to prevent infection of the uterus. Following parturition endometritis may still occur, especially is one or more of the mentioned predisposing factors is present.
==Clinical Signs==
'''Mucopurulent vaginal discharge''' should be evident on vaginal exam '''21 days or more post-calving'''. Discharge is relatively odourless (dependant on severity) and '''white''' in colour, hence the name 'whites'. The discharge should not be confused with '''lochial discharge''' or '''vaginitis'''. Rectal palpation should reveal a '''poorly-involuted''', '''oedematous uterus'''. On an individual or herd level there may be a history of '''subfertility'''.
==Diagnosis==
Diagnosis should be based on the '''calving history''' and '''clinical signs''' following '''vaginal''' and '''rectal''' exam. Vets may use a '''scoring system''' to categorise the '''colour''' and '''odour''' of the vaginal discharge which indicates how '''severe''' the infection is and whether '''treatment''' is necessary. Measurements of the '''uterine''' and '''cervical''' '''diameter''' may be included in the scoring system. Definitive diagnosis can only be achieved by '''endometrial biopsy''', however this is rarely indicated.
== Treatment ==
'''Greater success''' is achieved with '''milder cases''' of endometritis. Treatments available include [[Antibiotics|antibiotics]], '''hormones''' and '''intrauterine antiseptics''':
'''(1) Antibiotics'''
Various factors should be considered when selecting an antibiotic for the treatment of endometritis. '''Criteria for antibiotic''':
* appropriate efficacy in infected uterine environment
* appropriate efficacy against the causal bacteria
* no inhibition of natural uterine defense mechanisms
* appropriate concentration and duration of action in the infected uterine lumen
* little or no milk withdrawal period
* cost effective
* no detrimental effect on fertility
Generally, a '''broad spectrum antibiotic''', active against '''''Actinobaccillus pyogenes''''' and '''gram-negative anaerobes''' should be used. Ideal antibiotics are [[Cephalosporins|cephalosporins]] and [[Tetracyclines|oxytetracycline]] as they match the majority of criteria listed above. Some resistance to oxytetracyclines is reported and additionally some formulations cause irritation to the endometrium, therefore '''intrauterine cephalosporin''' should be considered the '''most effective antibiotic treatment'''.
[[Sulphonamides|Sulphonamides]], [[Aminoglycosides|aminoglycosides]], nitrofurazones and [[Penicillins|penecillins]] have decreased activity as a result of the uterine environment and bacteria present. [[Nitroimidazoles|Metranidazole]] and [[Chloramphenicol|chloramphenicol]] should not be used as they are banned from use in food-producing animals.
Some antibiotics are rapidly absorbed and distributed throughout the body, and in these cases it may be of more use to administer them parenterally.
'''(2) Hormones'''
'''Oestrogens:''' controversial treatment bases on the knowledge that the uterus is more resistant to infection during oestrus. It is not licensed in the EU for use in cattle.
'''Prostaglandins:''' PGF2a or analogues can be administered parenterally. They should be considered the '''treatment of choice if a corpus luteum is present'''. The administration of prostaglandins removes the inhibitory effect of progesterone on the uterus and induces oestrus, which both of these actions '''improve the uterine defense mechanisms'''. They may have an additional beneficial '''ecbolic effect''', aiding clearance of the lumenal contents. There is '''no milk withdrawal period''' for prostaglandins, making them ideal for use in dairy cattle.
These are mainly used in chronic cases.
'''(3) Antiseptics'''
'''Chlorhexidine''' and '''metakresol sulphonic acid''' (Lotagen) antiseptic administered '''intrauterine''' are reported to be a effective alternative to antibiotic treatment, however few studies have been carried out to confirm this and detrimental effects on fertility are reported.
==Prognosis==
Prognosis is '''dependant on the severity of infection and the effectiveness of treatment'''. Greater success is seen with mild cases of endometritis.
==References==
RVC staff (2009) '''Urogenital system''' RVC Intergrated BVetMed Course, ''Royal Veterinary College''
Andrews, Blowey, Boyd & Eddy (2004) '''Bovine Medecine - Disease and Husbandry of Cattle''' (2nd edition) ''Blackwell''
{{review}}
[[Category:Reproductive Disorders]][[Category:Uterus - Pathology]]
[[Category:Reproductive Diseases - Cattle]]
[[Category:Expert Review - Farm Animal]]