Assessing Prevalence of Endometritis and Associated Influence on Performance of Smallholder Zero-Grazed Dairy Cows in Gasabo District of Rwanda

Abstract

Endometritis is a uterine disease that interrupts cow reproductive cycles as a clinical (CLE) or subclinical (SCLE) condition between 21st and 90th days postpartum (dpp), resulting in suboptimal fertility, production and profitability in a herd. This study tested the hypothesis that suboptimal fertility and production performance of zero-grazed dairy cows on smallholder farms result from prevalent CLE and SCLE cases and multiple risk factors (RFs) at the cowand herd levels. The specific objectives were to determine: farmer perceived and observed endometritis prevalence; farmer perceived effective management interventions (MIs); risk factors; and endometritis influence on milk yield (MY) and reproductive performance. Sample farms (n=370) in Gasabo District of Rwanda were accessed through exponential nondiscriminative snowball sampling in a cross-sectional survey. Zero-grazed dairy cows (n=466) in their 21 to 60 dpp were diagnosed for CLE and SCLE cases using Metricheck device and Cytotape, respectively, and prospectively observed for fertility performance up to 210 dpp, and MY for 30 days post-endometritis diagnosis. Data analysis used the Best-Worst Scaling choice method to determine effective MIs, path analysis model to determine RFs, and general linear model to determine influence of endometritis on MY and reproductive performance. Endometritis prevalence was 3.2% by farmer estimation, but 70.2% observed at the cow-level with 67.2% CLE and 31.8% SCLE while observed prevalence at herd-level was 71.1% with 68.1% CLE and 34.4% SCLE. Of the MIs (n=20) assessed, 60.0% were farmer perceived as the most effective prevention and control. The top four MIs were consulting animal health service (ANHS) providers, not sharing equipment between farms, keeping cows in a clean and dry shed, and selecting sires for calving ease. Some cow- and herd-levels RFs were specific for CLE or SCLE cases and some others were common for both CLE and SCLE cases in smallholder zero-grazed dairy cows. Compared to cows’ negative for endometritis, the positive cows had longer days to first oestrus (median 85 vs 63 days), longer days-not pregnant (95.5 vs 63.0 days), lower pregnancy rate at first service (16.5% vs 32.7%), more services per pregnancy (1.3±0.1 vs. 1.1±0.0) and more anoestrus postpartum cows (48.4% vs. 11.7%). The milk loss during period of discarding was 7.3 ± 0.3 while decrease in MY resulting from endometritis was 1.4 ± 0.2 litres /cow/day. It is concluded that a combination of Metricheck device and Cytotape could optimise detection of endometritis, implementation of MIs reduces RFs and improves reproductive performance while treating endometritis positive cases using veterinary drugs having no residual effect in treated cows could be an alternative to minimise MY loss and associated economic loss.