Estrogen Administered at Final Milk Removal Accelerates Involution of Bovine Mammary Gland

¹ Department of Dairy and Poultry Sciences, University of Florida, Gainesville 32611

To evaluate whether estrogen hastened involution of mammary tissue, Holstein cows were injected with 4 ml of ethanol excipient (n = 21) or 15 mg of estradiol-17ß (n = 23) on each of the 4 d that preceded final milk removal. Dates of final milk removal (d 0) were designated as 60 d prior to expected dates of calving. Milk volumes were recorded, and samples were collected prior to the first and fourth injections. During the dry period, each mammary quarter within the cow was sampled once to collect secretions on dates that correspond to d 0, 3, 11, and 25 or 1, 7, 18, and 30 of the dry period. Milk synthesis and secretion declined abruptly because of treatment. The decreased concentrations of -lactalbumin, lactose, citrate, and potassium in secretions of controls, as well as the increased somatic cells, protein, lactoferrin, and sodium, occurred earlier in secretions from treated cows. These shifts of approximately 6 d, relative to days dry, suggested that exogenous estradiol increased the involution rate of mammary tissue.

Key Words: estrogen • mammary • involution • dry period

Submitted on March 6, 1995
Accepted on October 19, 1995

This article has been cited by other articles:

				L. Delbecchi and P. Lacasse Short Communication: Suppression of Estrous Cycles in Lactating Cows Has No Effect on Milk Production J Dairy Sci, February 1, 2006; 89(2): 636 - 639. [Abstract] [Full Text] [PDF]

				E E Connor, D L Wood, T S Sonstegard, A F da Mota, G L Bennett, J L Williams, and A V Capuco Chromosomal mapping and quantitative analysis of estrogen-related receptor alpha-1, estrogen receptors alpha and beta and progesterone receptor in the bovine mammary gland J. Endocrinol., June 1, 2005; 185(3): 593 - 603. [Abstract] [Full Text] [PDF]

				M. H. Faulds, H. Olsen, L. A. Helguero, J.-A. Gustafsson, and L.-A. Haldosen Estrogen Receptor Functional Activity Changes during Differentiation of Mammary Epithelial Cells Mol. Endocrinol., February 1, 2004; 18(2): 412 - 421. [Abstract] [Full Text] [PDF]

				K. C. Bachman and M. L. Schairer Invited Review: Bovine Studies on Optimal Lengths of Dry Periods J Dairy Sci, October 1, 2003; 86(10): 3027 - 3037. [Abstract] [Full Text] [PDF]

				J. A. Ford Jr., S. W. Kim, S. L. Rodriguez-Zas, and W. L. Hurley Quantification of mammary gland tissue size and composition changes after weaning in sows J Anim Sci, October 1, 2003; 81(10): 2583 - 2589. [Abstract] [Full Text] [PDF]

				M. S. Gulay, M. J. Hayen, K. C. Bachman, T. Belloso, M. Liboni, and H. H. Head Milk Production and Feed Intake of Holstein Cows Given Short (30-d) or Normal (60-d) Dry Periods J Dairy Sci, June 1, 2003; 86(6): 2030 - 2038. [Abstract] [Full Text] [PDF]

				A. V. Capuco, S. E. Ellis, S. A. Hale, E. Long, R. A. Erdman, X. Zhao, and M. J. Paape Lactation persistency: Insights from mammary cell proliferation studies J Anim Sci, March 1, 2003; 81(suppl_3): 18 - 31. [Abstract] [Full Text] [PDF]

				J. M. Haughian, R. Sartori, J. N. Guenther, A. Gumen, and M. C. Wiltbank Extending the Postpartum Anovulatory Period in Dairy Cattle with Estradiol Cypionate J Dairy Sci, December 1, 2002; 85(12): 3238 - 3249. [Abstract] [Full Text] [PDF]

				A. V. Capuco, M. Li, E. Long, S. Ren, K. S. Hruska, K. Schorr, and P. A. Furth Concurrent Pregnancy Retards Mammary Involution: Effects on Apoptosis and Proliferation of the Mammary Epithelium after Forced Weaning of Mice Biol Reprod, May 1, 2002; 66(5): 1471 - 1476. [Abstract] [Full Text]

				M. H. Faulds, K. Pettersson, J.-A. Gustafsson, and L.-A. Haldosen Cross-Talk Between ERs and Signal Transducer and Activator of Transcription 5 Is E2 Dependent and Involves Two Functionally Separate Mechanisms Mol. Endocrinol., November 1, 2001; 15(11): 1929 - 1940. [Abstract] [Full Text] [PDF]