| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
* University of Illinois, Urbana, and
and
AAFC-Dairy and Swine R & D Centre, Lennoxville, Quebec
Environmental influences on lactation efficiency are frequently associated with reductions in milk output. Heat stress, for example, leads to depressed feed intake and, subsequently, losses in production. Conversely, cold stress may limit nutrients available for milk synthesis. Fortunately, one environmental factor, photoperiod, can exert a positive effect on dairy performance when managed properly. Long days have consistently been shown to improve milk yield during established lactation. In addition, photoperiod management can be used to improve heifer growth and maximize accretion of lean tissue, including mammary parenchyma. There is, however, evidence of refractoriness to long day stimulation. Recent work has focused on the dry period as a time when photoperiod manipulation can influence subsequent milk production. In contrast to lactating cows, multiparous cows benefit from exposure to short days when the dry period is followed by long days or natural photoperiod after calving. Similarly, primiparous animals also respond positively to short days late in pregnancy when subsequently exposed to long days during lactation. Furthermore, emerging evidence suggests that short days positively influence immune function in cattle. Mechanistically, it appears that prolactin has a causal relationship with the observed dairy performance effects during the dry period and on immune function, via altered sensitivity to prolactin through differential expression of prolactin receptor in multiple tissues. The objectives of this paper include a review of fundamental aspects of photoperiod physiology, integration of applied and basic research findings, and development of management recommendations for the entire life cycle of the dairy cow to optimize performance.
Key Words: Photoperiod • Management • Immune Function
This article has been cited by other articles:
|
|
 |
|
  A. D. Morrissey, A. W. N. Cameron, and A. J. Tilbrook Artificial Lighting During Winter Increases Milk Yield in Dairy Ewes J Dairy Sci, November 1, 2008; 91(11): 4238 - 4243. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. M. Velasco, E. D. Reid, K. K. Fried, T. F. Gressley, R. L. Wallace, and G. E. Dahl Short-Day Photoperiod Increases Milk Yield in Cows with a Reduced Dry Period Length J Dairy Sci, September 1, 2008; 91(9): 3467 - 3473. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 G. E. Dahl Effects of short day photoperiod on prolactin signaling in dry cows: A common mechanism among tissues and environments? J Anim Sci, March 1, 2008; 86(13_suppl): 10 - 14. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. D. Hanigan, A. G. Rius, E. S. Kolver, and C. C. Palliser A Redefinition of the Representation of Mammary Cells and Enzyme Activities in a Lactating Dairy Cow Model J Dairy Sci, August 1, 2007; 90(8): 3816 - 3830. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. J. Collier, G. E. Dahl, and M. J. VanBaale Major advances associated with environmental effects on dairy cattle. J Dairy Sci, April 1, 2006; 89(4): 1244 - 1253. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. A. K. Salama, G. Caja, X. Such, R. Casals, and E. Albanell Effect of Pregnancy and Extended Lactation on Milk Production in Dairy Goats Milked Once Daily J Dairy Sci, November 1, 2005; 88(11): 3894 - 3904. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
T. L. Auchtung, A. G. Rius, P. E. Kendall, T. B. McFadden, and G. E. Dahl Effects of Photoperiod During the Dry Period on Prolactin, Prolactin Receptor, and Milk Production of Dairy Cows J Dairy Sci, January 1, 2005; 88(1): 121 - 127. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
N. C. Whitley and D. J. Jackson An update on estrus synchronization in goats: A minor species J Anim Sci, January 1, 2004; 82(13_suppl): E270 - 276. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
