Oorsig/Review
expressing E. coli in the uterus during the first
two days postpartum have impaired reproductive
performance (Bicalho et al., 2012, Machado et al.,
2012c) and are more likely to be infected with F.
necrophorum at 8-10 days postpartum(Bicalho et
al., 2012). F. necrophorum expresses a number of
virulence factors, but a leukotoxin (LKT) known
to be highly toxic to bovine neutrophils appears
to be of most importance. Adhesion to bovine
endothelial cells is mediated by virulence factor
FomA (Kumar et al., 2015). F. necrophorum is
synergistic with Trueperella pyogenes in etiology
of several conditions including abscesses, footrot,
summer mastitis and calf diphtheria (Nagaraja et
al., 2005) and this synergy contributes to uterine
disease as well (Dohmen et al., 2000, Bicalho et
al., 2012, Machado et al., 2012c). T. pyogenes
appears to be more prominent in uterine disease
later in the postpartum period – endometritis,
cervicitis and purulent vaginal discharge.
Diagnosis of metritis is usually uncomplicated
but affected cows should be examined thoroughly
to exclude peracute mastitis, abomasal
displacement, pneumonia, peritonitis or other
systemic disease. Traditionally, fever has been
regarded as an essential component of acute
puerperal metritis but it may not be prominent
(Benzaquen et al., 2007).
Acute puerperal metritis usually responds
favorably to systemic administration of
antimicrobial drugs.
If necessary, more
aggressive supportive therapy, including fluid
therapy, should be instituted. Many of the E.
coli involved in pathogenesis of acute puerperal
metritis are antibiotic resistant, but cephalosporin
antibiotics remain the best choice – for microbial
sensitivity and for uterine distribution (Bicalho
et al., 2010b). Although drainage of the fetid
uterine contents is intuitively appealing, the
uterus is friable and may be penetrated easily
by a siphon tube at this stage. Manipulation
of the uterus can result in bacteremia, and any
attempt at drainage should be avoided or at
least delayed until after beginning antimicrobial
treatment (Gilbert and Schwark, 1992). Many
antimicrobial drugs have been found to be useful
in the treatment of cows with acute puerperal
metritis. Several studies have found systemic
administration of ceftiofur to be effective in
advancing resolution of clinical signs (Drillich et
al., 2001, Zhou et al., 2001) but not in improving
fertility (Haimerl and Heuwieser, 2014). The
same is true for systemic ampicillin treatment
(Lima et al., 2014). Given concerns over antibiotic
resistance and residues, some have advocated
waiting two days before instituting antibiotic
treatment, given a self-cure rate of approximately
30 % (Haimerl and Heuwieser, 2014) There is
no evidence that other forms of treatment such
as estrogens (Risco and Hernandez, 2003) or oral
calcium gels (Hernandez et al., 1999) improve
clinical condition or reproductive response of
cows with metritis. Intrauterine administration
of antibiotics has generally not been found to
be beneficial; in one exception, high doses of
oxytetracycline were used for a protracted period
(Goshen and Shpigel, 2006). Many bacteria
isolated from cows with metritis are resistant to
tetracycline (Santos et al., 2010).
Most cows recover promptly from toxic puerperal
metritis with timely treatment, or sometimes,
spontaneously (McLaughlin et al., 2012). In rare
instances, fatal liver failure (Sweeney et al., 1988)
or amyloidosis (Johnson and Jamison, 1984)
may be complications of puerperal metritis.
Acute puerperal metritis increases the risk of
subsequent infertility (Moss et al., 2002, Elkjaer
et al., 2013, Toni et al., 2015). Cows with acute
puerperal metritis are at increased risk of later
purulent vaginal exudate or endometritis (Lima
et al., 2014).
Effective means of preventing metritis would be
extremely valuable to dairy producers. Although
reduced dry matter intake in the dry period is a
Table1. Incidence of metritis in half sib groups during one year in a single dairy farm
Sire Number of Daughters Proportion with Metritis (%)
B 213 23.5
D 296 10.1
A
C
138
191
39.1
21.5
Proportion differs significantly by sire (P < 0.0001). Note that these data have not been corrected for
age, season, obstetrical intervention or other factors that may influence incidence of metritis.
(K.N. Galvão & R.O. Gilbert, unpublished.)
14