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 Karcher, E. L. Articles by Donkin, S. S. Search for Related Content PubMed PubMed Citation Articles by Karcher, E. L. Articles by Donkin, S. S.

Effect of dietary carbohydrate and monensin on expression of gluconeogenic enzymes in liver of transition dairy cows¹

E. L. Karcher^*,2, M. M. Pickett, G. A. Varga and S. S. Donkin^*,3

^* Department of Animal Sciences, Purdue University, West Lafayette, IN 47907; and and Department of Dairy and Animal Science, The Pennsylvania State University, University Park 16802

³ Corresponding author: sdonkin{at}purdue.edu

Thirty-four multiparous Holstein cows were used in a randomized block design to evaluate the effects of feeding nonforage fiber sources (NFFS), monensin, or their combination on expression of gluconeogenic enzymes in the liver during the transition to lactation. The addition of 0 or 300 mg/d of monensin to a conventional (CONV) or NFFS prepartum diet was evaluated in a 2 x 2 factorial arrangement of treatments. The NFFS diet was formulated by replacing 30% of the forage component of the CONV diet with cottonseed hulls and soyhulls. The CONV and NFFS basal diets were fed at dry-off and continued through parturition. Monensin was fed from –28 d relative to calving (DRTC) through parturition. At calving, all cows were placed on the same diet. Liver biopsy samples obtained at –28, –14, +1, +14, and +28 DRTC were used to determine pyruvate carboxylase (PC) and cytosolic phosphoenolpyruvate carboxykinase (PEPCK-C) mRNA expression. Feeding NFFS resulted in greater (P < 0.05) prepartum DMI compared with the CONV diet. There was no effect of prepartum diets on postpartum DMI or average milk production to 56 d of lactation. Expression of PC mRNA was elevated (P < 0.05) at 1 d postpartum, but there was no effect of NFFS or monensin on PC mRNA abundance. Expression of PEPCK-C mRNA at calving was increased (P < 0.05) with prepartum monensin feeding. The data indicate that feeding monensin to transition cows induces hepatic PEPCK-C mRNA expression before calving. The increased expression of hepatic PEPCK-C mRNA with monensin feeding suggests a feed-forward mechanism of metabolic control in ruminants that links molecular control of gluconeogenesis with the profile of rumen fermentation end products.

Key Words: gene expression • monensin • transition dairy cow

This article has been cited by other articles:

				R. F. Cooke, J. D. Arthington, D. B. Araujo, G. C. Lamb, and A. D. Ealy Effects of supplementation frequency on performance, reproductive, and metabolic responses of Brahman-crossbred females J Anim Sci, September 1, 2008; 86(9): 2296 - 2309. [Abstract] [Full Text] [PDF]

				J. K. Toshniwal, C. D. Dechow, B. G. Cassell, J. A. D. R. N. Appuhamy, and G. A. Varga Heritability of Electronically Recorded Daily Body Weight and Correlations with Yield, Dry Matter Intake, and Body Condition Score J Dairy Sci, August 1, 2008; 91(8): 3201 - 3210. [Abstract] [Full Text] [PDF]

				Y.-H. Chung, M. M. Pickett, T. W. Cassidy, and G. A. Varga Effects of Prepartum Dietary Carbohydrate Source and Monensin on Periparturient Metabolism and Lactation in Multiparous Cows J Dairy Sci, July 1, 2008; 91(7): 2744 - 2758. [Abstract] [Full Text] [PDF]