| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1 Institute of Grassland and Environmental Research, Plas Gogerddan, Aberystwyth SY23 3EB, UK
2 Welsh Institute for Rural Studies, University of Wales, Aberystwyth, Llanbadarn Campus, Aberystwyth SY23 3AL, UK
We offered 48 multiparous Holstein-Friesian cows one of three different dry-period diets for 6 wk before predicted calving: A) a grass silage and barley straw mix (60:40 on a dry-matter basis), with a low protein content; B) grass silage only (medium protein); or C) grass silage plus 0.5 kg of high protein corn gluten meal (high protein)/d. A standard grass silage-based diet was offered to all cows following calving. All animals were blood sampled at weekly intervals during the dry period, and at wk 1, 3, 5, 7, 13, 17, and 21 of lactation. Nitrogen balance was measured in a subset of 12 cows (four per treatment) at 3 wk before calving, and at wk 8 and 18 of lactation. Nitrogen balance in the dry period increased significantly as dietary protein supply increased [9, 34, and 50 g of N/d (SED 8.8) for the three diets, respectively]. We measured no residual effects of dry-period treatment on N balance during lactation. Plasma concentrations of growth hormone became significantly higher in the late dry period in cows offered the silage and straw diet, although treatment differences disappeared after calving. Insulin concentrations were significantly affected by treatment throughout the dry period and indicated inadequate nutrient supplies from the low protein diet, leading to losses in body reserves of energy and protein. The results indicate that animals offered the low protein diet accumulated less N per day than is required for fetal development, suggesting that protein must have been repartitioned from maternal tissues.
Key Words: nitrogen balance • dry period • dairy cows
Submitted on October 12, 1999
Accepted on February 11, 2000
This article has been cited by other articles:
|
|
 |
|
  J. M. Moorby, M. R. F. Lee, D. R. Davies, E. J. Kim, G. R. Nute, N. M. Ellis, and N. D. Scollan Assessment of dietary ratios of red clover and grass silages on milk production and milk quality in dairy cows J Dairy Sci, March 1, 2009; 92(3): 1148 - 1160. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. M. Moorby, P. H. Robinson, W. J. Fisher, and R. T. Evans Comparison of Red Clover and Ryegrass Silage for Dry Cows and Influence on Subsequent Lactation Performance J Dairy Sci, September 1, 2008; 91(9): 3501 - 3511. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. A. Winkelman, T. H. Elsasser, and C. K. Reynolds Limit-Feeding a High-Energy Diet to Meet Energy Requirements in the Dry Period Alters Plasma Metabolite Concentrations but Does Not Affect Intake or Milk Production in Early Lactation J Dairy Sci, March 1, 2008; 91(3): 1067 - 1079. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. M. Moorby, R. J. Dewhurst, R. T. Evans, and J. L. Danelon Effects of dairy cow diet forage proportion on duodenal nutrient supply and urinary purine derivative excretion. J Dairy Sci, September 1, 2006; 89(9): 3552 - 3562. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. J. Dewhurst, W. J. Fisher, J. K. S. Tweed, and R. J. Wilkins Comparison of Grass and Legume Silages for Milk Production. 1. Production Responses with Different Levels of Concentrate J Dairy Sci, August 1, 2003; 86(8): 2598 - 2611. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
