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The three studies were conducted to 1) investigate the prevalence of subclinical endometritis (SCE) around breeding and its effect on first service conception rate (FSCR) in dairy cows, to 2) determine the correlation between periparturient serum concentrations of non-esterified fatty acids (NEFA), beta-hydroxybutyric acid (BHBA), bilirubin, and urea and the prevalence CE and SCE and to 3) compare systemic antibiotic treatment of clinical endometritis (CE) in dairy cows with ceftiofur with a treatment protocol consisting of two doses of prostaglandin F2α.
For the first study, a total of 201 Holstein-Friesian cows with no signs of CE were examined four hours after first artificial insemination (AI) for signs of SCE. Endometrial samples were collected from the uterus using the cytobrush technique. The proportion of polymorphonuclear (PMN) cells in the cytological sample was used to characterize an inflammation of the endometrium. Cows were categorized into three groups according to the proportion of PMN in the sample. Cows with 0 % PMN (n = 115) were assigned to group Zero, cows with >0 to15 % PMN (n = 59) to group Medium, and cows with >15 % PMN (n = 27) to group High. Pregnancy diagnosis was performed between days 38 to 44 after AI by palpation of the uterus and its contents per rectum. The FSCR was significantly higher in group Medium than in groups Zero and High (57.6 % vs. 39.1 % and 29.6 %, P < 0.05).
Primiparous cows were at higher risk of being classified into group Medium than multiparous cows (OR = 2.27, P = 0.01). A comparison with cows that were not examined for SCE showed that the collection of endometrial samples itself had no effect on FSCR.
In the second study serum samples were collected one week prior to parturition (wk -1), in the first week post partum (wk +1) and between 28 and 35 days post partum (wk +5) from 209 Holstein-Friesian cows to determine the concentrations of NEFA, BHBA, bilirubin, and urea. At wk +5, all cows were examined for signs of CE and SCE. Of 77 primiparous cows, 23.4 % were diagnosed with CE and 7.8 % with SCE. Of 132 multiparous cows, 15.9 % were diagnosed with CE and 15.2 % with SCE. For parameters that showed a correlation with SCE or CE, optimal predictor cut points were determined. Higher concentrations of urea at wk +1 were associated with increased odds of CE (OR = 1.7, P = 0.04) in primiparous cows.
A predictor cut point of 3.9 mmol/L (sensitivity: 61%, specificity: 70 %) was determined. In multiparous cows, higher concentrations of NEFA at wk -1 were associated with increased odds of CE and SCE (healthy vs. CE: OR = 9.1, P = 0.05; healthy vs. SCE: OR = 12.1, P = 0.04). A predictor cut point of 0.3 mmol/L (healthy vs. CE: sensitivity: 38 %, specificity: 87 %; healthy vs. SCE: sensitivity: 35 %, specificity: 89 %) was determined. Increasing concentrations of urea at wk +5 were associated with decreased odds of CE (healthy vs. CE: OR = 0.6, P = 0.01; SCE vs. CE: OR = 0.5, P = 0.03). A predictor cut point of 3.8 mmol/L (sensitivity: 52 %, specificity: 81%) was determined. For BHBA and bilirubin relationships with CE or SCE were not detected. The corresponding combinations of sensitivity and specificity of the determined predictor cut points were not satisfactory for practical use. Thus, the analysed parameters at the chosen time points cannot be recommended as predictors for CE and SCE in dairy cows.
The third study was conducted on two commercial dairy farms, housing a total of 1900 Holstein cows. All cows were examined 21 to 27 days post partum (dpp) by vaginal inspection. Cows with clinical signs of endometritis, i.e. mucopurulent or purulent vaginal discharge were randomly allocated to one of two treatment groups. Cows in group CEF (n=141) received 1 mg/kg BW of ceftiofur (i.m.) on three consecutive days. Cows in group CLP (n=140) received 0.5 mg of cloprostenol (i.m.) at the day of enrolment and 14 days later.
All cows were re-examined by vaginal inspection 42 to 48 dpp. Proportion of cows cured 42 to 48 dpp was 74.2 and 80.2 % in groups CEF and CLP, respectively (P > 0.05). AI submission rate, days to first service, days open and proportion of cows pregnant did not differ between the groups. Risk of conception after first insemination was higher (OR = 0.56, P = 0.045) in CLP than in CEF. In conclusion, the systemic treatment with 1.0 mg/kg BW of ceftiofur on three consecutive days in cows with signs of clinical endometritis 21 to 27 dpp was not superior to a treatment protocol consisting of two doses with cloprostenol.