Feeding Cattle in Australia

Cattle are ruminants — their four-compartment digestive system allows them to convert plant fibre, including mature pasture grasses and crop residues, into protein and energy through microbial fermentation in the rumen. This gives cattle a genuine competitive advantage over simple-stomached livestock in utilising low-quality roughage, but it also means that their nutritional requirements and deficiencies manifest differently from monogastric animals and must be understood in rumen terms to be managed effectively.

The primary nutritional requirements for beef cattle are energy (measured as metabolisable energy, ME, in megajoules per kilogram of dry matter), protein (as crude protein percentage of the diet dry matter), and a suite of minerals and vitamins, of which phosphorus, sodium, magnesium, copper, selenium, and cobalt are most commonly limiting in Australian conditions. Water is often overlooked but is the single most important nutrient — a cow in the last trimester of pregnancy or early lactation in hot Australian summer conditions may consume 80 to 100+ litres per day, and any restriction in water intake reduces feed intake and production proportionally.

The main nutritional constraint in Australian beef production is not protein or energy per se but the mismatch between the nutritional quality of available pasture and cattle requirements at specific stages of the production cycle. Mature native pasture at the end of the dry season or in winter has a crude protein content of 3 to 5% — well below the 7 to 8% minimum required for adequate rumen microbial function — and an ME of 6 to 7 MJ/kg, which is adequate for maintenance of a dry, non-lactating cow but insufficient for the demands of late pregnancy or early lactation. Targeted supplementation at these critical periods is more efficient than year-round supplementation at lower rates.

In the majority of Australian beef systems, pasture — whether improved sown pastures in higher-rainfall areas or native grass communities in the semi-arid and arid pastoral zones — provides 80 to 95% of the total nutritional input to the herd over the year. Pasture management is therefore cattle nutrition management, and any improvement in pasture quality and utilisation efficiency directly reduces supplementary feeding costs and improves cattle performance.

The key principles of pasture management for beef production are: maintaining adequate ground cover (a minimum of 50 to 70% ground cover in most Australian environments) to prevent soil erosion and maintain pasture productivity; managing stocking rate to match the available feed base in the current season rather than an average that assumes average conditions; and using rotational or cell grazing where paddock infrastructure allows, to give each paddock adequate rest and recovery time between grazing events.

Weed management in pastures is a significant and ongoing investment in productive capacity. Pasture weeds displace productive grass species, reduce available dry matter, and in some cases are toxic to cattle (for example, Paterson's curse, which causes liver damage in chronically exposed cattle, and certain poisonous plants in various regions). Herbicide programs, spelling to allow desirable species to reseed, and fertilisation to favour productive species over weeds are the primary tools.

Drought is a recurring reality in Australian cattle production, and every producer needs a drought management strategy before it is needed rather than improvising under pressure. The core decision in drought feeding is the cost comparison between feeding cattle through the drought versus destocking (selling or agisting cattle) and restocking when conditions improve — the calculations involve feed cost, cattle value, likely drought duration, and restocking cost and availability.

When drought feeding is the chosen strategy, the feeding program should prioritise survival of the breeding herd (cows and replacement heifers) over growing cattle (steers and surplus heifers), which can be sold for what the market offers rather than fed at a cost that may not be recovered. The priority feeding hierarchy is: pregnant cows in the last trimester (the highest nutritional demand and the highest loss if they abort or lose the calf), then lactating cows with young calves, then dry cows, then growing cattle.

Common drought rations for cattle include: hay (ideally tested for nutritional value before purchase — nutritional composition varies enormously between cuts and seasons), grain-based supplements (oats, wheat, barley, or sorghum, either whole or processed, introduced gradually to avoid grain-adapted acidosis), and commercial protein-energy blocks or loose lick supplements. The starting protein level in the supplement matters: cattle on mature native pasture (very low crude protein) need a supplement with a minimum crude protein of 25 to 30% to provide bypass protein that the rumen microbes cannot adequately supply from the base diet.

Introduce any new feed gradually — shift cattle onto grain over 3 to 4 weeks, increasing the proportion incrementally, to allow the rumen microbiome to adapt. Abrupt introduction of high-grain diets causes acidosis, which can kill cattle rapidly. Never introduce grain to cattle that have been on dry mature pasture by filling a trough and letting them eat freely — the consequences can be fatal.

Australian soils are among the oldest and most weathered on earth, and many regions are chronically deficient in specific minerals that are essential to cattle production. Unlike feed energy and protein deficiencies — which manifest relatively quickly as visible weight loss — mineral deficiencies are slow, insidious, and often difficult to attribute definitively without soil, pasture, or blood testing. The most economically significant mineral deficiencies in Australian cattle production are:

Phosphorus: The most widespread and economically significant mineral deficiency in Australian beef production. Phosphorus-deficient country (which covers much of northern and central Australia, including large areas of Queensland and the NT) produces pastures with phosphorus concentrations of 0.08 to 0.12% of dry matter — significantly below the 0.18 to 0.20% required for optimal production. Phosphorus deficiency causes reduced growth rates, poor body condition, reduced fertility, and pica (abnormal appetite, including bone chewing). Phosphorus supplementation through loose lick or liquid supplements is the standard management in deficient areas and one of the highest-returning inputs in northern Australian cattle production.

Copper: Copper deficiency occurs both from genuinely low copper soils and from secondary deficiency caused by high molybdenum or sulphate content, which antagonises copper absorption. Swayback (neurological disease in calves), poor coat colour (reddish-brown tint in black-coated cattle), and reduced growth and fertility indicate possible copper deficiency. Diagnosis requires liver biopsy (the most reliable indicator) rather than blood testing. Treatment with injectable copper or copper supplementation through licks, pellets, or ruminal boluses corrects deficiency.

Selenium: White muscle disease in calves (selenium deficiency in late pregnancy), poor conception rates, and retained placentas can indicate selenium deficiency, which is most common in southeastern Australia. Injectable selenium given to cows 4 to 6 weeks before calving prevents white muscle disease in calves; selenium-mineral licks or selenium-fortified fertiliser maintain levels in supplementation-accessible cattle.

Before investing in mineral supplementation programs, test your soils and ideally your cattle blood or liver values — not all deficiencies apply in all regions, and over-supplementation of some minerals (copper in particular) is toxic. Your local agricultural advisory service or a livestock nutritionist can guide appropriate testing and supplementation for your specific location.

Not all periods in the cattle production cycle have equal nutritional sensitivity. Three periods have disproportionate production impact if nutrition is inadequate:

Late pregnancy (last 60–90 days before calving): The foetus grows most rapidly in the last trimester, and the cow's nutritional demand peaks simultaneously. Cows below BCS 2.5 entering this period have elevated risk of pregnancy toxaemia (rare in cattle but possible in twin-bearing cows), low-birth-weight calves with reduced vigour and survival, reduced colostrum quality and quantity, and extended post-calving anoestrus that pushes conception dates into subsequent cycles, compounding calendar year reproductive losses.

Early lactation (calving to weaning): A lactating cow's energy requirement is 70 to 100% above maintenance — equivalent to the demand of growing a rapidly developing beef animal in addition to maintaining herself. In most Australian beef systems, cows lose condition between calving and weaning, particularly in systems where calving coincides with restricted pasture availability. The goal is to minimise condition loss through this period (BCS loss of 0.5 to 1.0 units is manageable; more than 1.0 unit indicates nutrition is inadequate) and to ensure cows are cycling and conceivable at joining despite this condition loss.

Joining: Cows that enter joining below BCS 2 have significantly reduced conception rates — the body-weight status at the time of ovulation and embryo implantation directly affects reproductive success. Cows that are losing condition at joining (negative nutritional balance) have worse conception rates than cows at the same BCS that are gaining condition. Even modest nutritional improvement in the 4 to 6 weeks before joining can significantly improve conception rates in condition-compromised herds — a management approach called "flushing" that is more commonly discussed for sheep but applies equally to cattle.