title: Total and differential somatic cell counts and N-acetyl-beta-D-glucosaminidase activity in mammary secretions during dry period.
abstract: Eighteen Holstein cows free of intramammary infection were sampled during dry period to measure changes in total SCC, differential cell counts, and N-acetyl-beta-D-glucosaminidase activity of milk or dry secretion. The design was to sample prior to and at drying off, two or more times during wk 1 of dry period, at 14 and 21 d of dry period, and after calving; 7 cows were sampled rotationally by quarters at 7, 14, and 21 d to avoid altering normal processes by repeated sampling. Total SCC of secretions declined just after drying off, increased to a peak of 6.593 (log10 scale) at 2 wk, and then declined slightly at 3 wk. Percentage of neutrophils rose from 33.3 at drying off to 83.8 at 1 wk and declined to 59.2 at 3 wk. Lymphocyte percentage declined in wk 1 of dry period but increased during wk 2 and 3. Activity of N-acetyl-beta-D-glucosaminidase in secretion rose throughout the first 3 wk of dry period.
authors.affiliation: USDA, ARS, Beltsville, MD.
authors.forename: R H
authors.initials: RH
authors.lastname: Miller
authors.forename: M J
authors.initials: MJ
authors.lastname: Paape
authors.forename: R R
authors.initials: RR
authors.lastname: Peters
authors.forename: M D
authors.initials: MD
authors.lastname: Young
mesh_terms: D000118:Acetylglucosaminidase / Q000032:analysis; D000818:Animals; D002417:Cattle / Q000502:physiology*; D002452:Cell Count / Q000662:veterinary; D005260:Female; D008321:Mammary Glands, Animal / Q000166:cytology / Q000201:enzymology / Q000378:metabolism* / Q000382:microbiology; D008892:Milk / Q000166:cytology* / Q000201:enzymology / Q000382:microbiology
chemical_list: D000118:Acetylglucosaminidase