J Vet Sci.  2004 Mar;5(1):5-9.

Assessment of the California mastitis test usage in smallholder dairy herds and risk of violative antimicrobial residues

• Shitandi A
• Kihumbu G

Abstract

This study evaluated how predictive the California Mastitis Test (CMT) is for sub-clinical mastitis under tropical smallholder dairy production conditions in Kenya. It intended to establish whether the CMT usage could be contributing to misdiagnosis and consequent mistreatment with animal drugs resulting in residue problems. Milk samples (n = 239) were aseptically collected from lactating cows in the Rift Valley of Kenya and tested using the CMT, somatic cell counts (SCC) and bacterial culture. The samples were also screened for violative drug residues using the commercial delvo test and compared to the milks mastitic status for possible association. There was a numerical but non-significant (p > 0.05) difference evident in the frequencies observed using the three different mastitis indicators. The prevalent bacterial species isolated from mammary glands with subclinical mastitis were Staphylococcus aureus (45.6%), coagulase-negative Staphylococci (13.0%), Streptococci (11.7%) and Escherichia coli 5.9%. There was an overall poor but significant (p < 0.05) correlation between the CMT and the violative antimicrobial residues in samples from all quarters, infected and non-infected respectively. The results suggest that the CMT use amongst the smallholder dairy sector as a mastitic indicator may not be a risk factor in violative antimicrobial residues problems in milk.

Keyword

California mastitis test; mastitic indicator; antimicrobial residues; milk

MeSH Terms

Animals
Anti-Infective Agents/*chemistry
Cattle
Cell Count/veterinary
Cross-Sectional Studies
Dairying
Drug Residues/*chemistry
Escherichia coli/isolation&purification
Female
Kenya
Mastitis, Bovine/*diagnosis/microbiology
Milk/chemistry/cytology/*microbiology
Reagent Kits, Diagnostic/standards/*veterinary
Rural Population
Staphylococcus aureus/isolation&purification
Streptococcus/isolation&purification
Tropical Climate