A reassessment of the epidemiology, pathogenesis and prevention strategies of bovine keratoconjunctivitis in Western Cape dairy cattle
type: CreativeWork
description: Bovine keratoconjunctivitis (BK) is an inflammatory eye condition of cattle that poses significant challenges to animal welfare, dairy and beef productivity, and antimicrobial stewardship in food-producing systems. The principal bacterial agents associated with BK, Moraxella bovis and M. bovoculi, are part of the core ocular surface microbiota in cattle. Rather than behaving as classical infectious agents, these symbionts demonstrate pathogenic potential under permissive conditions, while a range of animal- and herd-level factors modulate disease expression. This research aimed to address the scarcity of epidemiological data on BK in dairy systems and to facilitate evidence-based recommendations for its prevention and control in the Mediterranean climatic zone of South Africa’s Western Cape. A multifaceted investigative framework was employed, integrating a narrative literature review with causal mapping via directed acyclic graphs, analytical validations, and observational studies conducted on commercial dairy herds. Both cross-sectional and prospective cohort designs were used, supported by statistical modelling to define disease patterns and identify associated risk factors. A substantial BK prevalence of 19.4% (95% CI: 15.0–24.8%) was found among dairy cattle exposed to the region’s hot, dry summer conditions. Among heifers, the incidence density rate was 25.1 cases per 100 eye-years (95% CI: 20.7–30.4) over a twelve-month period, peaking at 55.9 cases per 100 eye-years during summer. Neither M. bovis nor M. bovoculi was consistently associated with clinical BK occurrence. Animal-level risk factors included breed, younger age, poor nutritional status, and concurrent facial or palpebral skin conditions such as ringworm. At herd level, intense solar radiation and elevated fly densities were associated with increased BK incidence. Management practices, including open herd strategies, inadequate shade provisioning, increased pyrethroid use in fly control programmes,…
abstract: Bovine keratoconjunctivitis (BK) is an inflammatory eye condition of cattle that poses significant challenges to animal welfare, dairy and beef productivity, and antimicrobial stewardship in food-producing systems. The principal bacterial agents associated with BK, Moraxella bovis and M. bovoculi, are part of the core ocular surface microbiota in cattle. Rather than behaving as classical infectious agents, these symbionts demonstrate pathogenic potential under permissive conditions, while a range of animal- and herd-level factors modulate disease expression. This research aimed to address the scarcity of epidemiological data on BK in dairy systems and to facilitate evidence-based recommendations for its prevention and control in the Mediterranean climatic zone of South Africa’s Western Cape. A multifaceted investigative framework was employed, integrating a narrative literature review with causal mapping via directed acyclic graphs, analytical validations, and observational studies conducted on commercial dairy herds. Both cross-sectional and prospective cohort designs were used, supported by statistical modelling to define disease patterns and identify associated risk factors. A substantial BK prevalence of 19.4% (95% CI: 15.0–24.8%) was found among dairy cattle exposed to the region’s hot, dry summer conditions. Among heifers, the incidence density rate was 25.1 cases per 100 eye-years (95% CI: 20.7–30.4) over a twelve-month period, peaking at 55.9 cases per 100 eye-years during summer. Neither M. bovis nor M. bovoculi was consistently associated with clinical BK occurrence. Animal-level risk factors included breed, younger age, poor nutritional status, and concurrent facial or palpebral skin conditions such as ringworm. At herd level, intense solar radiation and elevated fly densities were associated with increased BK incidence. Management practices, including open herd strategies, inadequate shade provisioning, increased pyrethroid use in fly control programmes,…
language: en
keywords: UCTD, Sustainable Development Goals (SDGs), Bovine keratoconjunctivitis, Moraxella, Epidemiology, Microbiota, Dairy cattle
date published: 2025
date modified: 2026-07-24T03:52:45Z
provider: University of Pretoria
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: University of Pretoria

PropertyValue
property ID: Handle
value: http://hdl.handle.net/2263/107747

PropertyValue
property ID: DOI
value: 10.25403/UPresearchdata.31205107