KEY MANAGEMENT COMPONENTS TO SUCCESSFUL OATS CROPS

Grazing

The ideal stage to start grazing is when plants are well anchored and the canopy has closed. Continuous grazing may be better for fattening stock than rotational grazing. Maintain adequate plant material to give continuous and quick regrowth, e.g. a minimum of 500 -700 kg/ha of dry matter.

For the best recovery after grazing, do not graze below 5 cm for prostrate varieties, and below 10 cm for more erect types. The higher grazing height is particularly important with erect growing varieties. Over-grazing greatly reduces the plant’s ability to recover

Grazing value

Financial returns from grazing can be based on:

• Changes in body weight throughout the grazing
• Weight gains of 1.2 kilograms per head per day for steers, and 200 grams per head per day for lambs are common
• Stock value before and after grazing
• Current agistment rates for stock, and Hand feeding costs for the
• Grazing oats significantly reduces the grazing pressure on
• pastures and can often reduce the necessity for hand feeding during
• Grazing oats enables autumn spelling of lucerne

Continuous grazing

With continuous grazing, stock remain on the forage oats for the entire feeding period and may or may not have access to alternative pasture. This is an easy management option that allows stock greater opportunity to select the young nutritious growth and maximises weight gain per head. In contrast, however, there is less efficient use of oats due to trampling and reduced regrowth potential.

Rotational grazing

Rotational grazing involves regularly moving stock between two or more oat paddocks, which allows the oats to regrow between grazing. Dry land oat crops can be grazed several times depending on rainfall, irrigation, nitrogen and timeliness and severity of grazing.

Strip grazing

Strip grazing is common on dairy farms where electric fences control stock access. It is used to minimise trampling losses, increase crop utilisation (less selection) and encourage regrowth for greater forage production. Fertilising following grazing is an option with irrigation or favorable rainfall. Be cautious of overgrazing as this impacts on recovery time.

Stocking rates

Suggested carrying capacities for fattening steers include:

• dryland—black soil—2 animals per hectare
• dryland—light soil—1.5 animals per hectare
• irrigation or favorable dryland—up to 5 animals per hectare.

Expected weight gains

• general range—0.7–1.2 kg per day
• weaner/yearling cattle—0.7–1.1 kg per day (average 0.9 kg)
• heavy steers (export)—0.8–1.2 kg per day (average 1.0 kg).

Haymaking

Some forage oat varieties are also suitable for haymaking. Cutting at the milky dough stage of grain fill will produce the highest yield of good-quality hay. Choose a variety with intermediate maturity, medium stem thickness and a high leaf-to-stem ratio.

After multiple cuts, the stems may increase in thickness. A high sowing rate (up to 80 kg/ha) will improve the quality of hay by helping to reduce the thickness of stems.

Oaten hay for the export market should be free of visible damage due to leaf and stem rust.

Nutrient Values of Oaten hay 

Animal Health – Scouring

Scouring is commonly seen on oats and is caused by a massive change in the diet from a dry, fibrous pasture to a lush, high-moisture (70–80%) grazing crop. Initially, the digestive system is purged, causing a loss of gut fill and a fast passage of feed. Also the rumen bacteria need time to adapt to the new feed. Cattle may lose condition and it often takes a few weeks for cattle to commence high weight gains.

Some methods of reducing scouring are allowing access to dry pasture, providing hay or limiting initial grazing times on forage oats if practical (e.g. 1 hour for first 4–7 days).

Ensure cattle are not hungry when going onto a new feed.

Good practice is to plant a late crop of sweet forage sorghum, to utilise in the introductory stages to the oats crop with rotational grazing. This assists with minimising nutrient loss and reduction of scouring and provides an ideal bridging crop given the high fibre/high energy content of the sweet forage sorghum

Enterotoxaemia (pulpy kidney), hypomagnesaemia (grass tetany), hypocalcaemia (milk fever), bone growth disorders in lambs (rickets), photosensitisation in sheep and nitrate poisoning are some of the possible livestock health disorders that might occur under certain growing and management conditions. Seek advice and plan to minimise the possibility of animal health disorders, ensure stock are vaccinated, and be careful with introducing stock to grazing crops. If you are topdressing crops be aware of levels of N in crop to avoid nitrate poisoning.

Red-tipping

Red-tipping of leaves is usually a symptom of nutrient deficiency on grazing oats. It is associated with low levels of nitrogen, phosphorus, potassium, zinc or sulphur

in the soil. Nitrogen deficiency is the most common cause. Red-tipping is not a symptom of rust infection. The reddish colour, seen mostly on the tips of mature leaves, is caused by the presence of a purple-red pigment called anthocyanin.

The intensity of the redness varies with the season. Early stages of the disorder show light-yellow veins running parallel

to the midrib of the leaf. In the later stages, the tips turn red. In cold, dry winters the colour deepens to almost purple, while in mild, wet winters it is a more washed-out orange-red. Affected plants are slightly stunted and less palatable for livestock. Red-tipping tends to occur over large areas of the crop where fertiliser application has not been adequate. Red-tipping can also be confused with barley yellow dwarf virus.

Red-tipping is more common than barley yellow dwarf virus in Queensland and Northern NSW. Red- tipping can be avoided by practicing good crop nutrition. In paddocks with a history of this problem, increase nitrogen rates to 70–80 kg of nitrogen per hectare and check whether other nutrients are adequate. Top-dressing can be used to correct the problem, but good rainfall after application is necessary and, as a consequence, results can be variable.

Rust management

Losses from leaf rust can be reduced by grazing or cutting rusted crops before the disease becomes severe. Given suitable conditions, it takes 7–14 days for a rust spore to infect and produce more spores. During this period, oat plants will normally produce several new leaves on each tiller.

During active growth of the crop, the upper canopy may remain free of rust symptoms. Therefore, it is necessary to regularly inspect the crop to monitor rust occurrence. If leaf rust is obvious below the top two leaves on each stem, the crop should be grazed or cut regardless of growth stage.

Tebuconazole (e.g. Folicur) and propiconazole (e.g. Tilt) are registered for control of leaf rust and stem rust on forage oats in Queensland. No information is available on economic thresholds for fungicide application in forage oats, but fungicide control is more likely to be economically viable in higher value crops (e.g. seed crops, high-quality hay crops).

Other tips for controlling leaf rust include the following:

• Select a variety with good resistance to leaf rust
• Avoid planting too early (before Feb – mid March) or too late (after June).
• Very early plantings (January to early March) of susceptible varieties should be avoided.