Type

Journal Article

Authors

Stephen T. Butler
P. Lonergan
A.C.O. Evans
Richard J. Dewhurst
Ian A. Hutchinson

Subjects

Veterinary

Topics
desiccation blood fat metabolism fat intake progesterone metabolism physiology eating animal feed pharmacology body weight dairy cattle poaceae dry matter intake animals dairying body composition lactation half life metabolic clearance rate drug effects milk dietary fats fat supplementation dairy cows progesterone female chemistry cattle dietary supplements metabolism

Effect of grass dry matter intake and fat supplementation on progesterone metabolism in lactating dairy cows (2012)

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.
Collections Ireland -> Teagasc -> Animal & Bioscience
Ireland -> Teagasc -> Animal & Grassland Research & Innovation Programme

Full list of authors on original publication

Stephen T. Butler, P. Lonergan, A.C.O. Evans, Richard J. Dewhurst, Ian A. Hutchinson

Experts in our system

1
S T Butler
Teagasc
Total Publications: 81
 
2
P. Lonergan
University College Dublin
Total Publications: 190
 
3
A.C.O. Evans
University College Dublin
Total Publications: 92
 
4
Richard J. Dewhurst
Teagasc
Total Publications: 10
 
5
I A Hutchinson
Teagasc
Total Publications: 10