The relationship between uterine pathogen growth density and ovarian function in the postpartum dairy cow

Abstract

In cattle, the first postpartum dominant follicle grows slower and produces less oestradiol in animals with high numbers of bacteria contaminating the uterine lumen. However, only bacteria that are uterine pathogens are correlated with severe clinical disease and an increased inflammatory response. It is unknown whether the effect on the ovary in relation to uterine bacterial contamination is associated with the presence of recognised uterine pathogens. Therefore, the present study examined the relationship between pathogenic bacteria in the postpartum uterine lumen, follicle growth and function and the formation of a competent corpus luteum. In addition, peripheral plasma concentrations of immune mediators were quantified. Swabs were collected from the uterine lumen of cattle on day 7 postpartum. Bacteria were cultured and identified and bacterial growth was scored semi-quantitatively. Animals were categorized into high or low recognized uterine pathogen contamination groups based on the number of colonies. Ovarian structures were monitored by daily transrectal ultrasonography and blood samples were collected. In animals with high numbers of uterine pathogens on day 7 postpartum, the diameter of the first postpartum dominant follicle was smaller and plasma oestradiol concentrations were lower. In addition, these animals had smaller corpora lutea, which produced less progesterone. Furthermore, animals with a high day 7 uterine pathogen growth density had higher peripheral concentrations of acute phase proteins. Thus, contamination of the uterus with recognized uterine pathogens is associated with ovarian dysfunction during the postpartum period. Furthermore, infection results in an increase in the production of inflammatory mediators.

Figure 1

Mean + SEM bacterial growth densities for A. pyogenes (A. pyo), E. coli, and Proteus (Prot) in the ipsilateral (■) and contralateral (□) uterine horns of Limousin-Friesian cattle on day 14 post partum.

Figure 2

Mean + SEM bacterial growth densities for A. pyogenes (A. pyo), E. coli, F. necrophorum (F. nec), P. melaninogenicus (P. mel) and Proteus (Prot) on day 7 postpartum in Holstein Friesian cows with a high (■) or low (□) day 7 UPGD. Values differ between UPGD groups * P < 0.05.

Figure 3

Mean + SEM bacterial growth densities for A. pyogenes (□) and E. coli (■) on days 7, 14, 21 and 28 postpartum for cows with a (a) high or (b) low day 7 UPGD. Values differ over time within group ^abP < 0.001 and between groups ^acP < 0.05.

Figure 4

Mean ± SEM (a) diameter of the first dominant follicle, (b) peripheral plasma oestradiol concentration between days 7 and 16 postpartum for cows with high (■) or low (□) day 7 UPGD. Values differ between groups within day * P < 0.05.

Figure 5

Mean ± SEM (a) diameter of the corpus luteum and (b) peripheral plasma progesterone concentrations between days 17 and 26 post partum for cows with high (■) and low (□) day 7 UPGD.

Figure 6

Mean + SEM peripheral plasma concentrations of PGFM on days 7, 14, 21 and 28 post partum for cows with high (■) or low (□) day 7 UPGD.

Figure 7

Mean + SEM peripheral plasma concentrations of (a) AGP, (b) SAA and (c) Haptoglobin on days 7, 14, 21 and 28 postpartum for cows with high (■) or low (□) day 7 UPGD. Values differ between UPGD groups within day *P < 0.05, **P < 0.01.