Effect of administration of a controlled-release monensin capsule on incidence of calving-related disorders, fertility, and milk yield in dairy cows.
OBJECTIVE
To determine the effect of a controlled-release monensin capsule administered at cessation of lactation on incidence of calving-related disorders, fertility, and milk yield in dairy cows.


METHODS
290 dairy cows treated with monensin and 290 untreated control cows.


METHODS
Treated cows received a capsule that released monensin at 335 mg/d for 95 days. Incidence of calving-related disorders; daily milk yield up to 20 days postpartum; test-day milk yield, fat, protein, and mature-equivalent 305-day milk production; and body condition score at calving were determined. Reproductive variables were conception rate at first service, pregnancy rate, and calving-to-conception interval.


RESULTS
Cows treated with monensin were 2.1 times as likely to develop dystocia and 0.8 times as likely to develop metritis as control cows. For milk yield, there was an interaction of treatment X time X parity. In multiparous cows, monensin significantly improved milk yield at test days 4 and 7. In addition, monensin increased body condition score at calving.


CONCLUSIONS
Despite increasing the likelihood of developing dystocia and metritis, administration of monensin improved the lactational performance of multiparous cows and may be a promising additive for use at the time of cessation of lactation.
Melendez
Pedro
P
Department of Large Animal Clinical Sciences, College of Veterinary Medicine, University of Florida, Gainesville, 32610-0136, USA.
Goff
Jesse P
JP
Risco
Carlos A
CA
Archbald
Louis F
LF
Littell
Ramon C
RC
Donovan
G Arthur
GA
D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000139:chemically induced*; D003692:Delayed-Action Preparations; D004420:Dystocia / Q000139:chemically induced / Q000662:veterinary; D004716:Endometritis / Q000139:chemically induced / Q000662:veterinary; D005260:Female; D005298:Fertility / Q000187:drug effects* / Q000502:physiology; D007476:Ionophores / Q000494:pharmacology; D007774:Lactation / Q000187:drug effects* / Q000502:physiology; D008892:Milk / Q000187:drug effects*; D008985:Monensin / Q000008:administration & dosage* / Q000009:adverse effects / Q000494:pharmacology*; D011247:Pregnancy
D003692:Delayed-Action Preparations; D007476:Ionophores; D008985:Monensin