Peer-reviewed veterinary case report
Effect of intramammary devices on the outcome of induced Escherichia coli infection of bovine mammary quarters.
- Journal:
- American journal of veterinary research
- Year:
- 1987
- Authors:
- Bright, S A et al.
Plain-English summary
In this study, researchers looked at how different types of intramammary devices (IMDs) affected the likelihood of infection in the udders of 18 Holstein cows that were healthy before the experiment. The cows were fitted with either smooth or rough IMDs, and some quarters were used as controls without devices. After a few weeks, the cows were exposed to a small amount of E. coli bacteria to see if they would get infected. The results showed that 88% of the quarters with smooth IMDs and all of the control quarters got infected, while only 41% of the quarters with rough IMDs were infected. This suggests that the rough IMDs might provide some protection against infection, but some cows showed signs of abnormal milk even before the bacteria were introduced. Overall, the treatment with rough IMDs partially worked in reducing infection rates compared to the smooth IMDs and controls.
Abstract
Eighteen Holstein cows, free of intramammary infection, were fitted with smooth (n = 9) or abraded (n = 9) intramammary devices (IMD) in 2 diagonally opposed quarters within 4 weeks after calving. The 2 other quarters of each cow were used as controls. Three to 6 weeks after IMD insertion, depending on when milk somatic cell counts returned to a base-line value of less than 4 X 10(5)/ml, all cows were subjected to bacterial challenge exposure in the front or rear quarters by intracisternal injection of about 30 colony-forming units of Escherichia coli/quarter. Challenge exposure was done immediately after milking. Three weeks after the initial bacterial exposure, the other quarter pairs were similarly challenge exposed. Quarter bacteriologic status, concentration of milk somatic cells, and clinical observations (rectal temperature, milk appearance, udder palpation, and general condition of the cow) were monitored. Infection developed in 14 of 16 (88%) quarters with smooth IMD vs 16 of 16 (100%) control quarters and in 7 of 17 (41%) quarters with abraded IMD vs 17 of 17 (100%) control quarters. The difference in infection frequency between quarters with smooth IMD and quarters with abraded IMD was significant (P less than 0.05). Protection against establishment of infection was associated with somatic cell counts greater than 8.0 X 10(5)/ml in milk collected immediately after milking (7 of 12 quarters) or 4 hours later (11 of 12 quarters). In 10 quarters (59%) of cows fitted with abraded IMD, secretory abnormalities appeared before bacterial challenge inoculation. Abnormal milk or visible blood was observed over periods varying from 2 weeks after insertion through the entire lactation.
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Search related cases →Original publication: https://pubmed.ncbi.nlm.nih.gov/3307564/