Prevalence of intramammary infection and teat canal colonization in unbred and primigravid dairy heifers.
Teat canal keratin (n = 461) and mammary gland secretions (n = 370) were collected from 31 unbred and 85 primigravid Jersey heifers from one research and three commercial dairy herds. Of 97 heifers from which secretion samples were obtained, 96.9% had intramammary infections and 29% showed clinical symptoms. Seventy-five percent of quarters were infected. Staphylococcus aureus were isolated from 36 (37.1%) heifers and 55 (14.9%) quarters. One hundred and eight (93.1%) heifers and 326 (70.7%) quarters had teat canals colonized with mastitis pathogens. Staphylococcus aureus were isolated from teat canal keratin samples from 36 (31%) heifers and 57 (12.3%) quarters. The three most common species isolated from secretion and teat canal keratin samples were Staphylococcus chromogenes, Staphylococcus hyicus, and S. aureus. Secretions from infected (n = 240) and uninfected (n = 85) quarters had SCC of 13.6 X 10(6)/ml and 5.7 X 10(6)/ml. Macrophages were the most numerous cell type in secretions of infected and uninfected quarters. Quarters with teat canal colonization, but with no intramammary infections, exhibited higher SCC in secretion (9.3 X 10(6)/ml) than quarters without both teat canal colonizations and intramammary infections (4.9 X 10(6)/ml). Data indicated that intramammary infections and teat canal colonizations were more prevalent and SCC higher than previously realized in dairy heifers.
Trinidad
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Mastitis Research Laboratory, Louisiana State University Agricultural Center, Homer 71040.
Nickerson
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SC
Alley
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TK
D000818:Animals; D002417:Cattle; D005260:Female; D007633:Keratins / Q000032:analysis; D007958:Leukocyte Count / Q000662:veterinary; D008214:Lymphocytes; D008264:Macrophages; D008321:Mammary Glands, Animal / Q000032:analysis / Q000166:cytology / Q000382:microbiology; D008414:Mastitis, Bovine / Q000453:epidemiology*; D009504:Neutrophils; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000453:epidemiology / Q000662:veterinary*; D015995:Prevalence; D013203:Staphylococcal Infections / Q000453:epidemiology / Q000662:veterinary*; D013210:Staphylococcus / Q000302:isolation & purification; D013211:Staphylococcus aureus / Q000302:isolation & purification; D013290:Streptococcal Infections / Q000453:epidemiology / Q000662:veterinary*; D013291:Streptococcus / Q000302:isolation & purification
D007633:Keratins