HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Duffield, T. Articles by Wilson, J. Search for Related Content PubMed PubMed Citation Articles by Duffield, T. Articles by Wilson, J.

A Field Study of Dietary Interactions with Monensin on Milk Fat Percentage in Lactating Dairy Cattle

T. Duffield^*, R. Bagg, D. Kelton^*, P. Dick and J. Wilson^*

^* Department of Population Medicine, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada, N1G 2W1
Elanco, Division Eli Lilly Canada Inc., Research Park Centre, Guelph, Ontario, Canada, N1G 4T2

Corresponding author: T. F. Duffield; e-mail: tduffiel{at}uoguelph.ca.

Ninety-one Ontario Holstein dairy herds were surveyed about their lactating cow ration and use of a premix containing monensin to identify possible dietary interactions with monensin on milk fat suppression. All herds were enrolled in Ontario Dairy Herd Improvement (DHI) milk recording, and results from four DHI tests were used. Herd mean fat tests were calculated only for cows between 100 and 200 d in milk to avoid potential confounding due to stage of lactation. Wet forage and total mixed ration (TMR) samples from all herds were evaluated for particle size using the Penn State Particle Size Separator. Of the herds using monensin (n = 58), the dose (per kg of dry matter) ranged from 9 to 14 mg/kg in TMR-fed herds and from approximately 9 to 23 mg/kg in herds in which concentrates were fed separately from forages (component-fed). Of the samples submitted for particle size evaluation, 15% of the haylage (n = 80), 14% of the corn silage (n = 79), and 42% of the TMR (n = 58) samples were classified as having low fiber. There was a significant negative univariable association between monensin and mean milk fat percentage. Monensin significantly reduced milk fat percentage in TMR-fed but not component-fed herds. Fiber length significantly interacted with monensin in TMR-fed herds: Herds that had low fiber in their TMR (6.0% in the top screen) were susceptible to milk fat decrease by monensin, whereas herds that had adequate fiber (>6.0%) were not. Monensin also significantly reduced milk fat percentage in herds receiving diets low in nonstructural carbohydrate (<40.2%) but not in those receiving diets high in NSC (40.2%). The results of this study suggest that there are significant interactions between monensin and certain dietary factors on milk fat suppression in Holstein dairy herds.

Key Words: monensin • milk fat • diet • lactating dairy cow

This article has been cited by other articles:

				O. AlZahal, N. E. Odongo, T. Mutsvangwa, M. M. Or-Rashid, T. F. Duffield, R. Bagg, P. Dick, G. Vessie, and B. W. McBride Effects of Monensin and Dietary Soybean Oil on Milk Fat Percentage and Milk Fatty Acid Profile in Lactating Dairy Cows J Dairy Sci, March 1, 2008; 91(3): 1166 - 1174. [Abstract] [Full Text] [PDF]

				A. M. Fairfield, J. C. Plaizier, T. F. Duffield, M. I. Lindinger, R. Bagg, P. Dick, and B. W. McBride Effects of Prepartum Administration of a Monensin Controlled Release Capsule on Rumen pH, Feed Intake, and Milk Production of Transition Dairy Cows J Dairy Sci, February 1, 2007; 90(2): 937 - 945. [Abstract] [Full Text] [PDF]

				J. L. Firkins, A. N. Hristov, M. B. Hall, G. A. Varga, and N. R. St-Pierre Integration of Ruminal Metabolism in Dairy Cattle J Dairy Sci, March 1, 2006; 89(e_suppl_1): E31 - E51. [Abstract] [Full Text] [PDF]