Oorsig / Review
appearance or optical density ( Machado et al ., 2012b ) of this fluid . Transrectal ultrasonography is also useful for diagnosis , but with moderate sensitivity and specificity ( Barlund et al ., 2008 ). The prevalence of endometritis in the immediate prebreeding period ( approximately 40 – 60 days postpartum ) is high in dairy cows and exerts a substantial negative effect on subsequent reproductive performance ( Gilbert et al ., 2005 , Dubuc et al ., 2010a , Cheong et al ., 2011b ), reducing conception to insemination and increasing pregnancy loss between 28 and 60 days after insemination .
The major risk factor for development of endometritis appears to be periparturient negative energy balance ( Hammon et al ., 2004 , Dubuc et al ., 2010b , Cheong et al ., 2011a ). Acute puerperal metritis in the early postpartum period increases risk of subsequent endometritis ( Cheong et al ., 2011b , Lima et al ., 2014 ). The major bacteria associated with endometritis are the same as those implicated in the pathogenesis of puerperal metritis – E . coli , Trueperella pyogenes and the gram-negative anaerobes Prevotella melaninogenica and Fusobacterium pyogenes . E . coli appears to be an early invader and has largely disappeared by the time endometritis is diagnosed . T . pyogenes is more often isolated contemporaneously with the diagnosis ( Bicalho et al ., 2012 , Machado et al ., 2012c , Santos and Bicalho , 2012 ).
Virtually all cows show evidence of mild uterine inflammation at 2 weeks postpartum . By 4 to 6 weeks postpartum , up to half of cows still have cytological endometritis . Attempts to diagnose endometritis before about 4 weeks postpartum are confounded by physiological inflammation associated with endometrial remodeling . Overall prevalence of endometritis at about 40 to 60 days postpartum is about 26 %, but herd prevalence ranges widely ( 5 % to over 50 %) ( Dubuc et al ., 2010a , Cheong et al ., 2011b ).
Endometritis reduces pregnancy to first AI and overall risk of pregnancy in the affected lactation ( Kasimanickam et al ., 2004 , Gilbert et al ., 2005 , Cheong et al ., 2011b ). The consequences of subclinical endometritis were less severe in first lactation animals ; although first service conception rate was diminished by endometritis in both age groups , overall time to pregnancy was not affected in primiparous cows with subclinical endometritis ( Cheong et al ., 2011b ).
Routine diagnosis of endometritis is seldom practical for all cows in a herd . However , it may be useful to examine a cohort of cows ( e . g .
20 cows ) by endometrial cytology to obtain insight into the prevalence of the condition on a specific farm . Then , if prevalence is high steps can be initiated to better manage transition cows to minimize periparturient negative energy balance .
Because individual cows are seldom diagnosed with endometritis , treatment is usually moot . Kasimanickam has shown that intrauterine infusion of a specific formulation of cefapirin ( Metricure ®, Merck Animal Health ) has beneficial effects on subsequent reproductive performance of affected cows . This product is not available in the USA . Several studies have examined prostaglandin administration for treatment or prevention of endometritis , without any evidence of efficacy , either for reducing incidence or improving reproduction ( Galvão et al ., 2009 , Dubuc et al ., 2011b , Haimerl et al ., 2012 ).
Prevention of endometritis rests largely on management of dietary intake and periparturient energy balance . Reduction of metritis incidence will reduce endometritis risk . Calving and postpartum hygiene are important .
Cervicitis and Purulent Vaginal Discharge
Although visible purulent vaginal exudate may accompany more severe forms of endometritis , it has become clear that cows may have visible reproductive tract exudate but be free of endometritis . It is assumed by most investigators that primary cervicitis is the major cause of a vaginal exudate in the absence of endometrial inflammation . Several lines of evidence support this conclusion . In pioneering work on identifying clinical findings associated with reduced fertility , LeBlanc et al . found that increased cervical diameter after 3 weeks postpartum was one factor ( along with purulent vaginal discharge ) predicting reduced likelihood of pregnancy ( LeBlanc et al ., 2002 ). Indeed , identification of an enlarged cervix was recognized as a harbinger of poor fertility much earlier ( Tennant and Peddicord , 1968 ). It now seems likely that these cows have cervical damage , sustained during parturition , and independent of endometritis , although the two conditions can co-exist . Dubuc et al . found that endometritis and purulent vaginal discharge had independent and additive detrimental effects on reproduction and that they had largely separate risk factors ( Dubuc et al ., 2010b ). Endometritis was predisposed to mainly by negative energy balance , while cervicitis / purulent vaginal discharge was most commonly a consequence of obstetrical complications , including RFM . Both conditions occur with higher
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