T-Stor >
Animal & Grassland Research & Innovation Programme >
Animal & Bioscience >

Please use this identifier to cite or link to this item: http://hdl.handle.net/11019/294

Title: Effect of grass dry matter intake and fat supplementation on progesterone metabolism in lactating dairy cows
Authors: Hutchinson, Ian A.
Dewhurst, Richard J.
Evans, A.C.O.
Lonergan, P.
Butler, Stephen T.
Keywords: Progesterone metabolism
Dairy cattle
Fat supplementation
Dry matter intake
Issue Date: 1-Sep-2012
Publisher: Elsevier Science B.V.
Citation: I.A. Hutchinson, R.J. Dewhurst, A.C.O. Evans, P. Lonergan, S.T. Butler. Effect of grass dry matter intake and fat supplementation on progesterone metabolism in lactating dairy cows. Theriogenology, 78(4), September 2012: 878-886. DOI:10.1016/j.theriogenology.2012.04.001
Series/Report no.: Theriogenology;Vol 78
Abstract: Progesterone (P4) metabolism in dairy cattle can be manipulated by alterations in dry matter intake and diet composition. Our objectives were to determine the effects of grazing allowance and fat supplementation on P4 metabolism in lactating dairy cows. Forty mid- to late-lactation Holstein-Friesian dairy cows were used in a completely randomized block design, with a 2 × 2 factorial arrangement of treatments. Cows were assigned to receive 1 of 2 pasture allowances (ad libitum allowance [AL], 9.5 kg dry matter per day, or restricted allowance [R] 7 kg dry matter per day) and 1 of 2 fat supplementation treatments (750 g per day saturated fat [F] or no fat supplement [NF]). All cows received an additional 4 kg per day of concentrate. Grass dry matter intake (GDMI) was measured 5 wk after the initiation of dietary treatment. Cows were treated with prostaglandin F2α (PGF2α) to eliminate the endogenous source of P4, and two intravaginal progesterone-releasing devices (CIDR) were inserted into each cow for a period of 8 days. Regular blood samples were taken before and after the removal of the intravaginal progesterone-releasing devices, and analyzed for P4 concentrations. The half-life (t½) and metabolic clearance rate (MCR) of P4 was calculated for each cow. There was no effect of GDMI or fat supplementation on the t½ or MCR of P4. There was a tendency for an interaction between GDMI and fat supplementation on the t½ of P4; cows on the restricted-F diet tended to have a longer P4 t½ than cows on the ad libitum-F diet. It was concluded that greater alterations in GDMI than achieved in the current study are required to change P4 metabolism. A combination of fat supplementation and restricted feeding slows P4 clearance, which may have beneficial implications for fertility.
Description: Peer-reviewed
This is the author’s version of a work that was accepted for publication in Theriogenology. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Theriogenology, volume 78 (4), September 2012: pages 878-886. DOI:10.1016/j.theriogenology.2012.04.001
URI: http://hdl.handle.net/11019/294
ISSN: 0093-691X
Appears in Collections:Animal & Bioscience

Files in This Item:

File Description SizeFormat
Hutchinson_et_al_P4_metabolism_Revised.pdf206.27 kBAdobe PDFView/Open

This item is protected by original copyright

View Statistics

Items in T-Stor are protected by copyright, with all rights reserved, unless otherwise indicated.


Valid XHTML 1.0! Teagasc - The Agriculture and Food Development Authority  2012  - Feedback