Livestock

Green grass warning

By Country News

Depending on where you are in the region you might have had quite a decent break already, with the start of some real pasture bulk soon to be available.

Others are just at the start of the process, where recent rain should soon send pasture or crops delicately emerging from the soil.

It is very tempting for those who have been spending day after day full hand-feeding stock to jump for joy, ditch the routine and turn the stock out into a paddock, letting them look after themselves for a while.

However tempting as this might be, it is a recipe for disaster as sudden changes to a ruminant diet are fraught with danger.

It is also important to determine that enough energy is present in the available feed to meet the demands of the livestock that will be grazing it.

What amounts to a green carpet is no good for cattle if they can’t physically get any of it into their mouths.

Most of you have spent a lot of time learning about the inner working of a rumen and how to work out a complete ration for livestock during the drought.

Now is the time to capitalise on this knowledge; use it, don’t lose it.

A rumen is a complicated vat of micro-organisms, which work to turn the feed eaten into energy and protein needed by the animal.

It takes at least two weeks, ideally more like three, to transition a ruminant onto a different diet.

This is the same if you are starting to feed grain or introducing green feed into the diet.

A sudden introduction of green feed can lead to metabolic imbalances, such as grass tetany and milk fever, due to low blood magnesium or calcium respectively, as the high potassium present blocks absorption of these minerals.

To try and prevent issues, sheep — especially those on grazing cereal crops — can be given a lick containing two parts limestone, two parts salt and one part Causmag.

Likewise, cattle can be fed Causmag-treated hay or a special transition diet designed for dairy cattle that are about to calve.

You may also use vitamin D injections for dairy cattle thought to be at high risk for milk fever.

Clinical cases can be treated with flow packs containing straight magnesium, straight calcium or 4-in-1, which contains calcium, magnesium, phosphorous and glucose.

You can also use oral drenches containing these elements.

Another good preventative strategy needed when starting livestock onto green feed is to vaccinate against clostridial disease using 3-in-1, 5-in-1, 6-in-1 or 7-in-1.

Animals that have not been vaccinated before need a priming dose and then a booster dose, ideally two weeks before moving them onto lush pasture.

If stock were vaccinated more than six months ago and are about to be moved onto very lush pasture, an additional booster may be necessary instead of waiting for the normal yearly interval.

Clostridial disease occurs because the nutrient-rich environment of the gut of livestock on green feed causes an overgrowth of these bacteria.

In the case of pulpy kidney, the bacteria, Clostridum perfringens type D, also produces a deadly toxin which can kill your nicest, biggest, fattest lambs just before they are able to top the local sale.

By using some preventative measures now you can ensure that green grass translates into green cash rather than green carcases.

—Linda Searle

district veterinarian

Murray Local Land Services