Login | Request Account (DAF staff only)

Phosphorus management of beef cattle in Northern Australia

Jackson, D., Dixon, R. M., Quigley, S. P., Schatz, T., Rolfe, J. W., Corbett, E., English, B. H., Sullivan, M. T., Chudleigh, F., Wellington, M., Callaghan, M. J. and Perry, L. (2023) Phosphorus management of beef cattle in Northern Australia. Project Report. Meat & Livestock Australia.

This is the latest version of this item.



In many of regions of northern Australia, phosphorus (P) is a serious nutritional limitation to cattle production, reducing herd efficiency and profitability.
• Phosphorus (P) is an essential nutritional requirement in cattle.
• Many soils across northern Australia are deficient in P, thus pastures growing on these soils do not contain enough P for cattle nutritional requirements.
• Signs of acute phosphorus deficiency include bone chewing, broken bones, peg-leg, poor body condition of breeders and botulism.
• Deficient animals respond best to P when pastures contain adequate energy and protein for cattle growth and reproduction.
• Soil analysis of P analysed using the Colwell P test (bicarbonate extracted phosphorus) can determine P status of the soil (where different soil types are present in a paddock, all should be tested).
• Deficiency is related to soil P status. As a general rule, where soil Colwell P levels: » are deficient (5mg/kg or less), all classes of stock are likely to respond to feeding P » are marginal (6–8mg/kg), young cattle are likely to respond to feeding P »exceed 8mg/kg, the economic benefit from feeding P diminishes.
• Responses to P supplement may be lower if animals running on P-deficient country have access to adjacent areas of high-P soils, such as frontage country.
• There are no simple diagnostic tests for the P status of cattle. Soil, blood and faecal P are useful indicators.
• A blood test for plasma inorganic phosphorus (PIP) should ideally be combined with diet quality measured by Faecal Near Infrared Reflectance Spectroscopy (F.NIRS) analysis of dung samples.
• Cattle grazing P-deficient pastures require a P supplement to meet their nutritional requirements, relying on bone mobilisation of P will erode herd productivity.
• Cattle grazing deficient pastures and fed an effective P supplement will eat 10–30% more pasture (deficient cattle have a depressed intake).
• If P is fed over the wet season on deficient country: » young growing stock can increase their growth by up to 90kg above base growth »breeders can increase weaning rates by 10–30% and mature breeders can maintain an additional 100kg over the wet season.
• Stocking rates must be matched to carrying capacity to ensure cattle have enough pasture for requirements.
• Supplement blocks and loose licks each have merits – to attain production goals, cattle must eat it. Monitor intakes and adjust recipe when required to avoid wasting money on supplement that sits in the paddock.
• On deficient pastures, wet season supplement intakes should aim to provide at least 6g P/head/ day to young growing cattle and 10g P/head/day to breeders.
• Dry season supplement mixes should contain a source of protein (e.g. urea) with sufficient P content to provide 2–5g P per day per animal.
• The economic benefits from feeding P are maximised when done in conjunction with other aspects of good herd management.
• Order P supplement early and make realistic calculations for how much P you need to last the entire wet season.

Item Type:Monograph (Project Report)
Corporate Creators:Department of Agriculture and Fisheries, Queensland
Business groups:Animal Science
Keywords:Final Report
Subjects:Agriculture > Agriculture (General) > Farm economics. Farm management. Agricultural mathematics
Agriculture > Agriculture (General) > Agriculture and the environment
Animal culture > Cattle
Animal culture > Feeds and feeding. Animal nutrition
Live Archive:22 Sep 2023 01:27
Last Modified:26 Apr 2024 01:31

Available Versions of this Item

Repository Staff Only: item control page


Downloads per month over past year

View more statistics