What does this research mean for the field?

The prevalence of bovine mastitis in Western Algeria is 59.7%, with 65.5% of affected cows showing positive cultures for Gram-negative bacilli, primarily Escherichia spp. Novelty: ClaimNovelty.NOVEL_FINDING. Consensus alignment: ConsensusAlignment.NEUTRAL.

What question did this study set out to answer?

This study aims to determine the prevalence of bovine mastitis and identify associated risk factors and Gram-negative bacteria isolates.

March 2, 2026Open Access

Bovine mastitis: Risk factors and isolation of Gram-negative bacteria in Western Algeria

Key Points

This study aims to determine the prevalence of bovine mastitis and identify associated risk factors and Gram-negative bacteria isolates.
Conducted a cross-sectional study in Western Algeria
Sampled 524 cows using clinical examination and the California mastitis test
Performed bacteriological assays on milk samples
Employed generalized linear mixed models to identify risk factors
Prevalence of mastitis was found to be 59.7% at the cow level
12.6% of cases were clinical mastitis (CM) and 47.14% were subclinical mastitis (SCM)
65.5% of mastitis-affected cows tested positive for Gram-negative bacilli
Most commonly isolated bacteria were Escherichia spp. (44%), Klebsiella spp. (23.1%), and Pseudomonas spp. (11.6%)
Risk factors for SCM included parity, visitor contact, and daily milk yield, while foremilk discarding reduced SCM risk.

Abstract

Across-sectional study was conducted inwestern Algeria between February and October 2024, aimed atdetermining the prevalence ofbovine mastitis, Gram-negative bacilli, and their associated risk factors. Atotal of524cows were sampled using clinical examination and the California mastitis test. Milk samples from the affected quarter were subjected tobacteriological assays. Three generalised linear mixed models were used toidentify the risk factors for clinical mastitis (CM) and subclinical mastitis (SCM), aswell asGram-negative bacilli isolates associated with bovine mastitis. Model selection was performed using the Akaike information criterion. The prevalence ofmastitis was 59.7% atthe cow level, ofwhich 12.6% was CM and 47.14% SCM. Overall, 65.5% ofthe mastitis cows showed apositive culture for Gram-negative bacilli. The most commonly isolated bacteria wereEscherichiaspp. (44%), Klebsiellaspp. (23.1%), and Pseudomonas spp. (11.6%). The parity, contact with visitors, and daily milk yield (l/day) were identified asrisk factors for SCM indairy cows. However, foremilk discarding reduced the risk ofdeveloping SCM. Ahistory ofmastitis, udder injuries, udder and leg hygiene scores, and parity were identified asrisk factors for CM. Nevertheless, none ofthe variables examined were risk factors for anudder infection bythe Gram-negative bacilli isolates.

Bookmark

View Full Paper