Incidence of calf morbidity and mortality and its associated risk factors in dairy farms of Ethiopia: Systematic review and meta-analysis

Abstract

Calf morbidity and mortality hinder herd replacement and sustainable dairy production. Although many studies have examined calf health outcomes in Ethiopia, reported incidence estimates vary widely. This systematic review and meta-analysis aimed to quantify pooled incidence rates of calf morbidity and mortality following the PRISMA guidelines. Peer-reviewed longitudinal studies with a minimum follow-up duration of six months were identified through systematic searches in PubMed, ScienceDirect, Scopus, Google Scholar, and Web of Science from January 1, 2000, to October 1, 2025. Risk of bias was assessed using the Joanna Briggs Institute appraisal tool. Random-effects model was used to estimate pooled incidence rates. Heterogeneity among studies was quantified using the inconsistency index (I²). Publication bias was assessed using funnel plot and Begg's rank correlation test. Sensitivity analysis was used to evaluate the influence of individual studies on pooled estimates. Among 481 identified records, nine studies were included for each outcome, comprising 2029 calves assessed for morbidity and 2595 calves assessed for mortality. The pooled incidence rates of calf morbidity and mortality were 29.32 (95% CI: 15.50-55.48) and 9.14 (95% CI: 5.31-15.72) per 100 calf-months, respectively. Substantial heterogeneity was observed across studies. Calf age, delayed first colostrum ingestion, and assisted calving were significantly associated with higher risks of morbidity and mortality. These findings indicate that calf morbidity and mortality remain major constraints in Ethiopian dairy systems and emphasize the need to strengthen farm biosecurity, improve colostrum management practices, and support animal health programs to reduce preventable calf morbidity and mortality.