title: Monensin use against Neospora caninum challenge in dairy cattle.
abstract: Using a randomized controlled trial design, a randomly allocated intervention group of 15 cows received a slow-release bolus that delivered 100 days of monensin. The negative control group of 15 cows received a placebo bolus that was identical to the monensin bolus, except without the monensin. Two weeks after bolus administration, all cows were challenged with a 2 ml subcutaneous injection of a live tachyzoite suspension. Whole blood and serum samples were collected from each cow every week for the first month post-challenge, and then every 2 weeks for the next 2 months. The extracted DNA from whole blood was tested for the Nc-5 gene fragment of Neospora caninum using a quantitative real time polymerase chain reaction. Serum was tested for antibodies to N. caninum using the IDEXX ELISA. Cows treated with monensin boluses had a significantly lower humoral immune response than cows treated with placebo boluses at one time point post-challenge (week 4 post-challenge). However, when adjusting for repeated measures within cows, the P value for this humoral difference was 0.098. No DNA for N. caninum was detected in either group, likely due to study design features.
authors.affiliation: Centre for Veterinary Epidemiological Research, University of Prince Edward Island, Charlottetown, PEI, Canada. jvanleeuwen@upei.ca
authors.forename: J A
authors.initials: JA
authors.lastname: VanLeeuwen
authors.forename: S
authors.initials: S
authors.lastname: Greenwood
authors.forename: F
authors.initials: F
authors.lastname: Clark
authors.forename: A
authors.initials: A
authors.lastname: Acorn
authors.forename: F
authors.initials: F
authors.lastname: Markham
authors.forename: J
authors.initials: J
authors.lastname: McCarron
authors.forename: R
authors.initials: R
authors.lastname: O'Handley
mesh_terms: D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D002417:Cattle; D002418:Cattle Diseases / Q000188:drug therapy* / Q000469:parasitology; D003048:Coccidiosis / Q000188:drug therapy / Q000469:parasitology / Q000662:veterinary*; D003049:Coccidiostats / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D003692:Delayed-Action Preparations; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D005260:Female; D008985:Monensin / Q000008:administration & dosage / Q000494:pharmacology / Q000627:therapeutic use*; D018688:Neospora / Q000187:drug effects* / Q000235:genetics / Q000276:immunology
chemical_list: D000913:Antibodies, Protozoan; D003049:Coccidiostats; D003692:Delayed-Action Preparations; D008985:Monensin