McGrath, Joseph; Savage, Darryl; Nolan, John V; Elliot, R

Author(s)

McGrath, Joseph

Savage, Darryl

Nolan, John V

Elliot, R

Publication Date

2012

Abstract

Active absorption of phosphorus (P) from the alimentary tract is promoted by increased concentrations of active vitamin D [1,25(OH)₂D₃] in blood; however, the production of this active vitamin is determined by plasma concentrations of calcium (Ca) and not P. As a consequence, diets of adequate Ca content, but insufficient P, will not promote active P absorption. Dietary supplements of 25OH-vitamin D (25OHD), the precursor of 1,25(OH)₂D₃, may stimulate P absorption and P retention of ruminants consuming diets marginally deficient in P. To evaluate this hypothesis, steers (n = 18) were fed a pelleted low-quality roughage diet containing an adequate Ca concentration (0.68%). Nine steers received a supplement of 25OHD mixed into their feed, at a rate of 3.25 mg/head.day, before pelleting. The other nine steers were fed the Control diet without supplementation. All steers were individually housed for 10 days before being moved into metabolism crates for a further 3-day period. The steers which received the diet containing 25OHD exhibited increased retention of P and Ca, ~4 and 3 g/day, respectively. Blood samples were taken before the adaptation period and then daily during the period in the metabolism crates. Plasma concentrations of both P and Ca were increased by 25OHD supplementation throughout the collection period. Addition of 25OHD to the diet of grazing animals may reduce the need for P supplementation programs and improve productivity.

Citation

Animal Production Science, 52(6 & 7), p. 636-640

ISSN

1836-5787

1836-0939

Link

https://hdl.handle.net/1959.11/10842

Publisher

CSIRO Publishing

Title

Phosphorus and calcium retention in steers fed a roughage diet is influenced by dietary 25OH-vitamin D

Type of document

Journal Article

Entity Type

Publication

Author(s)	McGrath, Joseph Savage, Darryl Nolan, John V Elliot, R
Publication Date	2012
Abstract	Active absorption of phosphorus (P) from the alimentary tract is promoted by increased concentrations of active vitamin D [1,25(OH)₂D₃] in blood; however, the production of this active vitamin is determined by plasma concentrations of calcium (Ca) and not P. As a consequence, diets of adequate Ca content, but insufficient P, will not promote active P absorption. Dietary supplements of 25OH-vitamin D (25OHD), the precursor of 1,25(OH)₂D₃, may stimulate P absorption and P retention of ruminants consuming diets marginally deficient in P. To evaluate this hypothesis, steers (n = 18) were fed a pelleted low-quality roughage diet containing an adequate Ca concentration (0.68%). Nine steers received a supplement of 25OHD mixed into their feed, at a rate of 3.25 mg/head.day, before pelleting. The other nine steers were fed the Control diet without supplementation. All steers were individually housed for 10 days before being moved into metabolism crates for a further 3-day period. The steers which received the diet containing 25OHD exhibited increased retention of P and Ca, ~4 and 3 g/day, respectively. Blood samples were taken before the adaptation period and then daily during the period in the metabolism crates. Plasma concentrations of both P and Ca were increased by 25OHD supplementation throughout the collection period. Addition of 25OHD to the diet of grazing animals may reduce the need for P supplementation programs and improve productivity.
Citation	Animal Production Science, 52(6 & 7), p. 636-640
ISSN	1836-5787 1836-0939
Link	https://hdl.handle.net/1959.11/10842
Publisher	CSIRO Publishing
Title	Phosphorus and calcium retention in steers fed a roughage diet is influenced by dietary 25OH-vitamin D
Type of document	Journal Article
Entity Type	Publication

Phosphorus and calcium retention in steers fed a roughage diet is influenced by dietary 25OH-vitamin D

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