|
|
||||||||
Michigan State University, East Lansing 48824
ABSTRACT
Knowledge of genetic relationships between characteristics of lactation curves and lactation yields is essential for joint selection for both. An equation, yt = atbexp(–ct), was chosen to depict individual lactation curves for 5,927 first lactations by Holsteins in 557 herds in Michigan Dairy Herd Improvement where yt is daily milk yield at day t in lactation, a is yield at time zero, b is ascent to peak, and c is decline after peak. Genetic correlations for 305-day milk yield with initial production (a), ascent to peak (b), descent after peak (c), and peak yield were –.37, .40, 0, and .91.
From empirical results from applied selection indexes, selecting for both increase of ascent to peak and peak yield did not decrease 305-day milk substantially. Rankings of sires on these indexes were similar to their rankings on milk yield alone. Attempts to decrease peak yield and increase persistency decreased milk yield greatly.
1 Michigan Agricultural Experiment Station Journal Article No. 10749.
This article has been cited by other articles:
![]() |
J. P. Sanchez, I. Misztal, I. Aguilar, B. Zumbach, and R. Rekaya Genetic determination of the onset of heat stress on daily milk production in the US Holstein cattle J Dairy Sci, August 1, 2009; 92(8): 4035 - 4045. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. Togashi and C. Y. Lin Economic weights for genetic improvement of lactation persistency and milk yield J Dairy Sci, June 1, 2009; 92(6): 2915 - 2921. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. A. D. R. N. Appuhamy, B. G. Cassell, and J. B. Cole Phenotypic and genetic relationships of common health disorders with milk and fat yield persistencies from producer-recorded health data and test-day yields J Dairy Sci, April 1, 2009; 92(4): 1785 - 1795. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. J. Wilson, Y. T. Grohn, G. J. Bennett, R. N. Gonzalez, Y. H. Schukken, and J. Spatz Milk Production Change Following Clinical Mastitis and Reproductive Performance Compared Among J5 Vaccinated and Control Dairy Cattle J Dairy Sci, October 1, 2008; 91(10): 3869 - 3879. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. Togashi and C. Y. Lin Genetic Modification of the Lactation Curve by Bending the Eigenvectors of the Additive Genetic Random Regression Coefficient Matrix J Dairy Sci, December 1, 2007; 90(12): 5753 - 5758. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. A. D. R. N. Appuhamy, B. G. Cassell, C. D. Dechow, and J. B. Cole Phenotypic Relationships of Common Health Disorders in Dairy Cows to Lactation Persistency Estimated from Daily Milk Weights J Dairy Sci, September 1, 2007; 90(9): 4424 - 4434. [Abstract] [Full Text] [PDF] |
||||
![]() |
B. Harder, J. Bennewitz, D. Hinrichs, and E. Kalm Genetic parameters for health traits and their relationship to different persistency traits in German Holstein dairy cattle. J Dairy Sci, August 1, 2006; 89(8): 3202 - 3212. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. I. Weller, E. Ezra, and G. Leitner Genetic analysis of persistency in the israeli holstein population by the multitrait animal model. J Dairy Sci, July 1, 2006; 89(7): 2738 - 2746. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. Togashi and C. Y. Lin Efficiency of Different Selection Criteria for Persistency and Lactation Milk Yield J Dairy Sci, May 1, 2004; 87(5): 1528 - 1535. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |