Grazing winter cereal crops - 3 simple tips

Grazing cereals are widely used across southern Australia during the cooler months. They typically have high winter growth rates, high carrying capacities, and high nutritional values. Grazing winter cereals can be an excellent means of overcoming the winter feed gap and easing the grazing pressure on pasture paddocks, but they don’t come without risk - there are a few basic animal health considerations to take into account:

Minerals

Calcium and magnesium are the big ones here. Cereal crops are notoriously low in both. Pregnant, lactating, and growing stock all have higher requirements for calcium and magnesium, so they’re at most risk of deficiency. If stock are low in calcium or magnesium, they may go down and even die due to hypocalcaemia (milk fever) or grass tetany.

Supplementing stock with calcium and magnesium is therefore warranted. Home-made loose licks are effective and affordable. Try mixing coarse salt, agricultural lime and causmag at a 2:2:1 ratio and have on offer in the paddock ad lib. Beware - causmag has a bitter taste, so sometimes it helps to slowly introduce it to the mix over a week or so to allow stock to get accustomed to it.

Vaccines

Cereal crops are high in water-soluble carbohydrates, and this puts stock at an increased risk of an overgrowth of clostridial bacteria in the gut, resulting in pulpy kidney and sudden death.

A booster vaccine (for example ‘5-in-1’) a couple of weeks before going out onto a crop is highly advisable. It’s a cheap, simple, and effective measure to help avoid pulpy kidney losses during the change in diet.

Nitrates

Nitrate poisoning is rare, but can be a risk. Nitrates are present in lush green feeds, especially those with a history of nitrogen fertiliser application. Ruminants can generally cope just fine with high nitrate feeds as they have the unique ability to convert nitrates into nitrite, and then into ammonia, which can actually be used by the rumen.

It is only when nitrate levels suddenly overload the animal’s ability to convert the nitrate quickly enough that problems arise. The result is a toxic build-up in the bloodstream that can cause sudden death. The most common instance is when hungry stock have been held in the yards for a day or two before being let out onto a lush green paddock where they ravenously eat and overload on nitrates.

The take=home message - never suddenly introduce hungry stock to lush green feed – fill them up on hay first and shift them on later in the day rather than in the morning.

To chat more about livestock health and grazing cereals, get in touch with your local District Vet or Livestock Officer by contacting your nearest LLS office.