title: Hot topic: effects of frequent milking in early lactation on milk yield and udder health.
abstract: A field study was conducted to evaluate the influence of milking frequency (3 or 6 times/d [3x or 6x, respectively]) during the initial 21 d of lactation on milk and milk component yield and mammary gland health as indicated by somatic cell count. During 2 seasons, spring and fall, multiparous cows were milked 6 times/d until d 21 of lactation and then returned to the 3 times/d frequency for the remainder of lactation (6x; n = 9). Multiparous cows milked 3 times/d from the beginning of lactation served as a control group (3x; n = 17). With the exception of milking frequency, all other aspects of management, including housing, milk harvesting, and feeding, were identical between the groups and were consistent with industry norms. Retrospective analysis of Dairy Herd Improvement Association records was used to evaluate milk yield, milk component yield, and somatic cell scores. As expected, 6x cows produced more milk on the first test day than 3x cows. Compared with 3x cows, higher milk yields persisted for 6x cows from test day 2 through 6, indicating a persistent effect of early lactation milking frequency on milk yield potential for that lactation. Milk component yield followed a similar pattern: 6x cows produced significantly more protein, fat, and total solids than did control cows throughout the study. With regard to udder health, 6x cows had lower somatic cell counts at the first test day relative to 3x cows and had reduced somatic cell scores for the first 3 mo of lactation, which suggests that early lactation milking frequency influences the mammary gland capacity to resist infection in addition to improving milk production efficiency.
authors.affiliation: Department of Animal Sciences, University of Illinois, Urbana 61801, USA. gdahl@uiuc.edu
authors.forename: G E
authors.initials: GE
authors.lastname: Dahl
authors.forename: R L
authors.initials: RL
authors.lastname: Wallace
authors.forename: R D
authors.initials: RD
authors.lastname: Shanks
authors.forename: D
authors.initials: D
authors.lastname: Lueking
mesh_terms: D000818:Animals; D002417:Cattle / Q000502:physiology*; D002452:Cell Count; D003612:Dairying / Q000379:methods*; D005260:Female; D007774:Lactation / Q000502:physiology*; D008055:Lipids / Q000032:analysis; D008321:Mammary Glands, Animal / Q000502:physiology*; D008892:Milk / Q000737:chemistry / Q000166:cytology; D008894:Milk Proteins / Q000032:analysis; D010298:Parity; D011388:Prolactin / Q000502:physiology; D012189:Retrospective Studies
chemical_list: D008055:Lipids; D008894:Milk Proteins; D011388:Prolactin