Effect of reaming the papillary duct of cows' teats on keratin removal and penetrability of the duct to implanted Escherichia coli endotoxin.
Penetrability of the bovine teat duct to Escherichia coli endotoxin solution was measured before and after reaming the duct with a polypropylene tube, a steel twist drill bit, or a fluted drill point. There was some evidence of a transient increase in penetrability for one or two milkings following reaming but most ducts were not rendered penetrable to endotoxin. Histological examination of ducts after reaming showed that although the loosely packed superficial keratin was effectively removed a continuous smooth keratin layer remained covering the epithelium. These observations are discussed with respect to the possible mechanisms responsible for maintaining the defensive barrier of the duct to bacterial penetration.
W D
WD
Schultze
A J
AJ
Bramley
D000818:Animals; D002417:Cattle / Q000502:physiology*; D004731:Endotoxins / Q000633:toxicity*; D004848:Epithelium / Q000502:physiology; D004926:Escherichia coli; D005260:Female; D007633:Keratins / Q000502:physiology*; D007774:Lactation; D008321:Mammary Glands, Animal / Q000502:physiology*; D008414:Mastitis, Bovine / Q000209:etiology*; D010539:Permeability; D011247:Pregnancy
D004731:Endotoxins; D007633:Keratins