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.
Mastitis Research Laboratory, Louisiana State University Agricultural Center, Homer 71040.
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Trinidad
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Nickerson
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TK
Alley
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