| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1 Centre for Dairy Research, Department of Agriculture, The University of Reading, Earley Gate, Reading RG6 6AJ England
2 BOCM Pauls Ltd., PO Box 39, 47 Key Street, Ipswich IP4 1BX England
Two experiments were conducted to determine effects of postrumen starch infusion on milk production and energy and nitrogen utilization in lactating dairy cows. In experiment 1, four cows in early lactation fed grass silage and concentrates were continuously infused into the duodenum with water or 700, 1400, or 2100 g of purified maize starch daily for 10 to 12 d in a 4 x 4 Latin square design with 2-wk periods. Starch infusion increased milk yield linearly and decreased milk fat concentration in a quadratic manner such that increases in fat-corrected milk and calculated milk energy yield were minimal except at the highest rate of infusion. Changes in milk energy output suggest that even at the highest infusion rate metabolizable energy supplied by infused starch was used for tissue energy or oxidized. In experiment 2 energy and nitrogen balance were measured in four cows in late lactation fed a mixture of dehydrated lucerne, grass silage, and concentrates during the last 6 d of 2-wk abomasal infusions of 1200 g of purified wheat starch daily or water in a balanced switchback design with 5-wk periods. Measurements of fecal starch concentration indicated nearly all the starch infused was digested, but decreased fecal pH and apparent nitrogen digestion suggested an increase in hindgut starch fermentation. Starch infusion decreased urine nitrogen output in part because of increased tissue nitrogen retention but had no effect on milk nitrogen output. In absolute terms, numerical decreases in feed energy intake and energy digestion reduced the recovery of starch energy infused as digestible and metabolizable energy, but in terms of changes in total energy supply with starch infusion, 79% was recovered as metabolizable energy. Starch infusion had no effects on heat or milk energy but increased net energy for lactation due to a numerical increase in tissue energy, implying that in late-lactation cows, starch digested postruminally was used with high efficiency for tissue energy retention as protein and fat.
Key Words: starch • postrumen digestion • energy metabolism • nitrogen utilization
Submitted on February 5, 2001
Accepted on June 5, 2001
This article has been cited by other articles:
|
|
 |
|
  E. Norberg, H. Volden, and O. M. Harstad Technical Note: Assessment of Recovery Site of Mobile Nylon Bags for Measuring Ileal Digestibility of Starch in Dairy Cows J Dairy Sci, January 1, 2007; 90(1): 418 - 421. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. F. Gressley and L. E. Armentano Effect of Abomasal Pectin Infusion on Digestion and Nitrogen Balance in Lactating Dairy Cows J Dairy Sci, November 1, 2005; 88(11): 4028 - 4044. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. C. Taylor and M. S. Allen Corn Grain Endosperm Type and Brown Midrib 3 Corn Silage: Site of Digestion and Ruminal Digestion Kinetics in Lactating Cows J Dairy Sci, April 1, 2005; 88(4): 1413 - 1424. [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]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
