| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
* Department of Dairy Science, University of Wisconsin, Madison 53706
Research Centre, Agriculture and Agri-Food Canada, Lethbridge, AB, Canada T1J 4B1
Corresponding author:
D. K. Combs; e-mail:
dkcombs{at}facstaff.wisc.edu.
Our study investigated the effects of, and interactions between, level of dietary ruminally fermentable carbohydrate (RFC) and forage particle size on milk production, nutrient digestibility, and microbial protein yield for dairy cows fed one level of dietary NDF. Eight cows (61 days in milk) were assigned to four treatments in a double 4 x 4 Latin square. Treatments were arranged in a 2 x 2 factorial design; finely chopped alfalfa silage (FS) and coarse alfalfa silage (CS) were combined with concentrates based on either dry cracked shelled corn (DC; low RFC) or ground high-moisture corn (HMC; high RFC). Diets were fed ad libitum as a total mixed rations with a concentrate to forage ratio of 61:39. Diets based on DC had a predicted NEL content of 1.73 Mcal/kg dry matter (DM), while HMC diets contained 1.80 Mcal/kg DM. Diets averaged 18.7% CP, 24.0% NDF, 18.3% ADF, and 27.4% starch on a DM basis. Mean particle size of the four diets was 6.3, 2.8, 6.0, and 3.0 mm for DCCS, DCFS, HMCCS, and HMCFS, respectively. Increasing level of RFC decreased dry matter intake (DMI) from 25.0 to 23.8 kg/d and organic matter intake from 22.3 to 21.1 kg/d, but intake was not affected by particle size. Milk production averaged 44.0 and 26.8 kg/d solids corrected milk (SCM) and was not affected by diet, but increasing level of RFC tended to increase milk yield. Efficiency of milk production, expressed as SCM/DMI, increased from 1.06 to 1.14 when level of RFC was increased. Milk composition or yield of milk components was not affected by diet, and averaged 3.53% fat, 3.11% protein, 1.55 kg/d fat, and 1.36 kg/d protein. Total tract digestibility of DM and OM increased from 71.4 to 73.0% and 72.4 to 76.1% for DM and OM, respectively, when level of RFC was increased. Total tract digestibility of fiber was unaffected by diet, but total tract starch digestibility increased from 93.1 to 97.4% when HMC replaced DC. Total urinary excretion of the purine derivatives uric acid and allantoin increased from 415 to 472 mmol/d when level of RFC was increased, and calculated microbial N supply increased from 315 to 365 g/d. When expressed as per kilogram of digestible OMI, increasing level of RFC tended to increase microbial N supply (20.4 vs. 22.2 g/kg). Cow productivity was not affected by forage particle size and ruminally fermentable carbohydrates in this study.
Abbreviation key: CS = coarse silage, DC = dry corn, DOMI = digestible organic matter intake, eNDF = effective NDF, ERD = effective rumen degradability, FS = fine silage, HMC = high moisture corn, RFC = ruminally fermentable carbohydrate
Key Words: particle size • ruminally fermentable carbohydrate • production • digestibility
This article has been cited by other articles:
|
|
 |
|
  S. K. Bhandari, S. Li, K. H. Ominski, K. M. Wittenberg, and J. C. Plaizier Effects of the Chop Lengths of Alfalfa Silage and Oat Silage on Feed Intake, Milk Production, Feeding Behavior, and Rumen Fermentation of Dairy Cows J Dairy Sci, May 1, 2008; 91(5): 1942 - 1958. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Q. Zebeli, J. Dijkstra, M. Tafaj, H. Steingass, B. N. Ametaj, and W. Drochner Modeling the Adequacy of Dietary Fiber in Dairy Cows Based on the Responses of Ruminal pH and Milk Fat Production to Composition of the Diet J Dairy Sci, May 1, 2008; 91(5): 2046 - 2066. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
W. Z. Yang and K. A. Beauchemin Altering Physically Effective Fiber Intake Through Forage Proportion and Particle Length: Digestion and Milk Production J Dairy Sci, July 1, 2007; 90(7): 3410 - 3421. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. K. Bhandari, K. H. Ominski, K. M. Wittenberg, and J. C. Plaizier Effects of Chop Length of Alfalfa and Corn Silage on Milk Production and Rumen Fermentation of Dairy Cows J Dairy Sci, May 1, 2007; 90(5): 2355 - 2366. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Rustomo, O. AlZahal, N. E. Odongo, T. F. Duffield, and B. W. McBride Effects of Rumen Acid Load from Feed and Forage Particle Size on Ruminal pH and Dry Matter Intake in the Lactating Dairy Cow J Dairy Sci, December 1, 2006; 89(12): 4758 - 4768. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
W. Z. Yang and K. A. Beauchemin Physically effective fiber: method of determination and effects on chewing, ruminal acidosis, and digestion by dairy cows. J Dairy Sci, July 1, 2006; 89(7): 2618 - 2633. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
W. Z. Yang and K. A. Beauchemin Increasing the physically effective fiber content of dairy cow diets may lower efficiency of feed use. J Dairy Sci, July 1, 2006; 89(7): 2694 - 2704. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Q. Zebeli, M. Tafaj, H. Steingass, B. Metzler, and W. Drochner Effects of Physically Effective Fiber on Digestive Processes and Milk Fat Content in Early Lactating Dairy Cows Fed Total Mixed Rations J Dairy Sci, February 1, 2006; 89(2): 651 - 668. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. Leonardi, K. J. Shinners, and L. E. Armentano Effect of Different Dietary Geometric Mean Particle Length and Particle Size Distribution of Oat Silage on Feeding Behavior and Productive Performance of Dairy Cattle J Dairy Sci, February 1, 2005; 88(2): 698 - 710. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. A. Wattiaux and K. L. Karg Protein Level for Alfalfa and Corn Silage-Based Diets: II. Nitrogen Balance and Manure Characteristics J Dairy Sci, October 1, 2004; 87(10): 3492 - 3502. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. S. Einarson, J. C. Plaizier, and K. M. Wittenberg Effects of Barley Silage Chop Length on Productivity and Rumen Conditions of Lactating Dairy Cows Fed a Total Mixed Ration J Dairy Sci, September 1, 2004; 87(9): 2987 - 2996. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. C. Plaizier Replacing Chopped Alfalfa Hay with Alfalfa Silage in Barley Grain and Alfalfa-Based Total Mixed Rations for Lactating Dairy Cows J Dairy Sci, August 1, 2004; 87(8): 2495 - 2505. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
W. C. Stone Nutritional Approaches to Minimize Subacute Ruminal Acidosis and Laminitis in Dairy Cattle J Dairy Sci, July 1, 2004; 87(13_suppl): E13 - 26. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. M. Calberry, J. C. Plaizier, M. S. Einarson, and B. W. McBride Effects of Replacing Chopped Alfalfa Hay with Alfalfa Silage in a Total Mixed Ration on Production and Rumen Conditions of Lactating Dairy Cows J Dairy Sci, November 1, 2003; 86(11): 3611 - 3619. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. M. Krause, D. K. Combs, and K. A. Beauchemin Effects of Increasing Levels of Refined Cornstarch in the Diet of Lactating Dairy Cows on Performance and Ruminal pH J Dairy Sci, April 1, 2003; 86(4): 1341 - 1353. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
K. M. Krause and D. K. Combs Effects of Forage Particle Size, Forage Source, and Grain Fermentability on Performance and Ruminal pH in Midlactation Cows J Dairy Sci, April 1, 2003; 86(4): 1382 - 1397. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
