19/10/2026
🌱🐂 BRIGALOW COUNTRY HAS PLENTY OF PHOSPHORUS… BUT ARE OUR CATTLE GETTING ENOUGH? 🤔
For as long as I can remember, I’ve heard producers tell me:
💬 “Brigalow country has plenty of phosphorus.”
💬 “We don’t need to supplement our cattle.”
💬 “Phosphorus supplements are too expensive.”
💬 “She’ll be right!”
Well, here’s something worth thinking about…
Over the past few months, my eyes have nearly gone square reviewing soil test results from grazing properties across Queensland.
And one thing keeps jumping off the page.
Extremely low levels of plant-available phosphorus, often associated with other soil nutrient imbalances.
Now, here’s where I think we need to challenge some long-held assumptions.
Just because phosphorus is present in the soil doesn’t necessarily mean it’s available to the pasture. And just because we’re growing plenty of grass doesn’t mean that grass is supplying enough phosphorus to meet our livestock’s requirements.
There are actually three different things we need to consider:
🌱 1. Phosphorus in the soil
Brigalow soils can contain considerable reserves of phosphorus, but not all of it is readily available for plant uptake. Soil chemistry, phosphorus fixation, pH and other nutrient interactions can influence how much phosphorus is available to the pasture.
🌾 2. Phosphorus in the pasture
The phosphorus concentration in grasses such as Buffel can vary with soil fertility, seasonal conditions, plant maturity and growth stage.
A pasture can produce a substantial amount of dry matter and still be relatively low in phosphorus.
However, low soil-test phosphorus doesn’t automatically mean the pasture is phosphorus deficient. We need to understand what the plant is actually taking up.
🐂 3. Phosphorus requirements of our livestock
This is where things get particularly interesting.
Our cattle don’t eat soil test results. They eat pasture!
And the amount of phosphorus they require depends on their class of livestock, growth rate, reproductive status and overall diet.
A dry cow, a lactating breeder and a growing steer can have very different phosphorus requirements.
So the real question isn’t simply how much phosphorus is in our Brigalow soils. It’s whether the pasture our cattle are consuming is supplying enough phosphorus to meet their production requirements.
And if it isn’t, what are we doing about it?
We have decades of research across northern Australia demonstrating the benefits of phosphorus supplementation where livestock diets are deficient.
Yet how often does the conversation focus on the cost of supplementation rather than the potential cost of NOT supplementing?
And let’s not forget, this isn’t just about breeder fertility!
What about our growing cattle?
Research has demonstrated additional annual liveweight gains of around 30–40 kg per head in young cattle grazing phosphorus-deficient country when appropriately supplemented.
But let’s put some practical numbers around it.
💰 Say you’re running 300 growing cattle through the wet season.
For this example, let’s assume:
🐂 Phosphorus supplement costs $1,600 per tonne delivered.
🐂 Each animal consumes an average of 60 grams per day over a 150-day feeding period.
🐂 That’s 9 kg of supplement per head, costing $14.40 per animal.
Allow another $4.20 per head for distribution, labour and other feeding costs.
Total supplementation cost: $18.60 per head.
At a liveweight cattle price of $4/kg, those animals only need to gain an additional 4.65 kg each to cover the supplementation cost on a simple liveweight-value basis.
Now imagine the response was an additional 15 kg per head.
That’s:
✅ $60 additional gross liveweight value per head.
✅ $18.60 supplementation cost per head.
✅ $41.40 per head potential margin above supplementation costs.
Across 300 head, that’s $12,420 in additional potential value before other costs and adjustments.
And that’s using a 15 kg response, not the larger annual responses demonstrated in some phosphorus-deficient grazing systems.
Of course, these are illustrative figures, not a guaranteed return. Actual intake, animal responses and sale prices will vary, and additional liveweight doesn’t always translate directly into extra sale revenue.
And here’s an important point: I’m not suggesting every producer should automatically start feeding phosphorus because their soil tests show low available phosphorus.
Soil testing helps us understand the nutrient limitations of our pasture system.
Pasture testing and an assessment of the livestock’s diet help us understand what phosphorus our animals are actually consuming.
And animal performance, livestock class and appropriate diagnostic testing help determine whether supplementation is warranted.
Soil phosphorus management and livestock phosphorus supplementation are two different management decisions, but they’re connected through the pasture our cattle eat.
With the 2026–27 wet season approaching, and producers looking towards potential market opportunities in 2027, shouldn’t we be positioning our livestock to convert the pasture we grow into kilograms of saleable beef as efficiently as possible?
Because the real opportunity isn’t simply feeding more supplement.
It’s understanding what our country is supplying, identifying what our livestock are missing, and investing where there’s a measurable return.
Perhaps it’s time we challenged the assumption that just because Brigalow country contains phosphorus, our livestock are necessarily getting enough of it.
And perhaps the most expensive phosphorus supplement is the one we decided we couldn’t afford to feed, when our cattle actually needed it!
👉 So who’s assessing their wet-season phosphorus requirements for BOTH breeders and growing cattle this year?
And more importantly, who’s measuring whether their supplementation program is actually paying?