Use of reagent test strips for diagnosis of endometritis in dairy cows.

The use of leukocyte esterase (LE), protein, and pH tests were evaluated on widely available urinary test strips (Multistix 10 SG; Bayer Corporation, Elkart, IN, USA) on uterine lavage samples as a potential cow-side test for the diagnosis of cytologic endometritis. Uterine lavage samples of 563 lactating Holstein cows between 40 and 60 days postpartum from 28 herds were evaluated. Endometrial cytology was used as the reference for endometritis, with a cutoff point of ≥10% neutrophils. All three (LE, protein, and pH) were increased in cows with cytologic endometritis and the associations were highly significant. Optimal cutoff points determined by receiver operating characteristic analysis for LE, protein, and pH were ≥++, ≥300 mg/dL, and ≥7.0, respectively. Combining the results for LE and pH improved the performance of the test strip, but this resulted in a group of cows (20.6% of cows) which were approximately equally likely (46% with endometritis and 54% without endometritis) to have cytologic endometritis or not, and therefore could not be accurately classified. The direct relationship between reagent strip test and reproductive performance was also evaluated. Reproductive impairment due to endometritis was restricted to multiparous cows; significantly decreased reproductive performance was observed for multiparous cows with lavage fluid LE ≥+++ (154 vs. 115 median days not-pregnant), as well as cows with pH ≥ 7.0 (150.5 vs. 111.5 median days not-pregnant), but not in cows with high protein, even at the highest cutoff point. In conclusion, reagent strip test results were strongly associated with cytologic endometritis and reproductive impairment; however, in comparison with conventional cytology, the performance of reagent strip as an alternative test was relatively poor and may require further refinement.

Effects of diagnostic low-volume uterine lavage shortly before first service on reproductive performance, culling and milk production.

The objective was to evaluate if uterine sampling by low-volume uterine lavage, done shortly before the end of the voluntary waiting period, affected reproductive performance, milk production, or culling. Approximately 20 cows (40 and 60 d postpartum) were sampled in each of 38 herds (total, 752 cows), whereas all remaining cows concurrently between 40 and 60 d were a non-sampled reference cohort (n = 2,252 cows). There was an interaction between parity and sampling for first-service conception, calving to conception interval, and milk production. When stratified by parity, there was a tendency for impaired reproductive performance in sampled primiparous cows compared with non-sampled primiparous cows (Odds Ratio for pregnancy to first-service = 0.78 (95% C.I. 0.58-1.04). The Hazard Ratio for pregnancy in sampled primiparous cows was 0.89 (95% C.I. 0.77-1.04) compared to non-sampled primiparous cows. Sampling did not affect first-service conception rate (Odds Ratio for pregnancy Odds ratio (OR) for pregnancy = 1.03; 95% C.I. 0.80-1.33) or calving-to conception interval in multiparous cows (Hazard Ratio = 1.04; 95% C.I. 0.91-1.18). Sampling did not affect culling risk (Hazard Ratio HR = 0.92; 95% C.I. 0.77-1.11) after accounting for covariates. After stratification by parity, milk production was not affected by sampling except in fourth- and fifth-parity cows where sampled cows produced more milk than non-sampled cows after controlling for first test-day milk production and days-postpartum at first test-day. In conclusion, sampling by low-volume uterine lavage did not have significant detrimental effects on reproduction, culling, or milk production. However, there was a tendency for lower first-service conception in sampled primiparous cows, but the procedure appeared to be benign in multiparous cows.

Cow-level and herd-level risk factors for subclinical endometritis in lactating Holstein cows.

The objectives of this study were to obtain prevalence estimates for subclinical endometritis (SCE), determine cow- and herd-level risk factors, and evaluate the reproductive consequences of SCE. A cross-sectional study was used to determine prevalence and risk factors with cows followed in a prospective study to determine reproductive outcomes. Lactating Holstein cows were sampled between 40 and 60 d in milk using low-volume uterine lavage, and cytology was evaluated to determine SCE status. In total, 779 cows from 38 herds were used in the analysis. The cow-level prevalence of SCE was 25.9%. Within-herd level prevalence ranged from 4.8 to 52.6% (median 26.3%, interquartile range 15.6 to 33.3%). Cow-level risk factors identified were ketosis [odds ratio (OR) 3.83; 95% confidence interval (CI) 1.82-8.07], acute metritis (OR 1.86; 95% CI 1.05-3.30], and the interaction between milk production and parity. Primiparous cows that produced more milk had increased odds of having SCE, whereas multiparous cows that produced more milk had decreased odds of having SCE. Herd-level risk factors identified were housing early postpartum cows on bedded packs (herd-level SCE=36.1%), which increased herd prevalence of SCE by 16.7% (SE 5.58) compared with early postpartum cows housed in freestalls (herd-level SCE=19.4%), and straw bedding in the calving pen, which decreased herd prevalence of SCE by 10.7% (SE 3.59) compared with herds that used other bedding material. In this study, primiparous cows with and without SCE had similar reproductive performance; however, multiparous cows with SCE had median days open 44 d longer (159 d; 95% CI 126-186 d) compared with unaffected multiparous cows (115 d; 95% CI 106-132 d).