title: Production and health of pasture-fed dairy cattle following oral treatment with the ionophore lasalocid.
abstract: The aim of the study was to evaluate the effect of feeding the ionophore lasalocid on the productivity and health of seasonally calving, pasture-fed dairy cows. Dairy cows (n = 1020) from 4 herds were enrolled in a split-herd, prospective intervention study. Cows were blocked by breed and age, ranked on previous production, and then assigned to 2 treatment groups. Treatment cows were each exposed to 300 to 350 mg of lasalocid/d commencing 3 wk before and ending 18 wk after the start of the seasonal calving period. Milk production was determined on 3 occasions for each cow at approximately monthly intervals (herd tests 1 to 3), body condition score was determined fortnightly, and all disease occurrences were recorded. Lasalocid treatment increased milk volume milk protein and milk fat production by approximately 2%, without altering milk composition. Fewer lasalocid-treated cows than control cows (7.3 vs. 11.6%, respectively) were diagnosed with clinical mastitis. Lasalocid treatment of pasture-fed dairy cows resulted in reduced mastitis incidence and increased milk production without changes in body condition or negative effects on metabolic processes as monitored by metabolite concentrations.
authors.affiliation: Animal Health Centre, Morrinsville, New Zealand. smcdoug@ahc.co.nz
authors.forename: S
authors.initials: S
authors.lastname: McDougall
authors.forename: L
authors.initials: L
authors.lastname: Young
authors.forename: F M
authors.initials: FM
authors.lastname: Anniss
mesh_terms: D020155:3-Hydroxybutyric Acid / Q000097:blood; D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D001823:Body Composition; D002417:Cattle / Q000502:physiology*; D004032:Diet; D004972:Estrus Detection; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D006304:Health Status; D007476:Ionophores / Q000008:administration & dosage*; D007774:Lactation; D007832:Lasalocid / Q000008:administration & dosage*; D008055:Lipids / Q000032:analysis; D008414:Mastitis, Bovine / Q000517:prevention & control; D008892:Milk / Q000737:chemistry; D008894:Milk Proteins / Q000032:analysis; D011247:Pregnancy; D011446:Prospective Studies; D012621:Seasons
chemical_list: D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007476:Ionophores; D008055:Lipids; D008894:Milk Proteins; D020155:3-Hydroxybutyric Acid; D007832:Lasalocid