How to transition stock onto green feed

PRODUCTION ADVICE - MARCH 2020 - ANIMAL HEALTH

By Linda Seale
District Veterinarian
P: 03 5881 9919 | M: 0427 629 740 | E: linda.searle@lls.nsw.gov.au

With a bit of rain, you might be starting to get a bit of growth. Tempting as it is to rely on this green pick, there are a couple of key points to remember.

Transition slowly

Always transition ruminants to a new diet slowly. Ideally, this should take at least two, ideally three, weeks. The rumen relies heavily on all the bugs in it to digest the feed. Different types of bugs break down different types of feed, and it takes time to repopulate the space with the right sort.

Check energy levels

Make sure there is enough energy in the feed for your stock. Stock can waste a lot of energy chasing green pick around a paddock if it is too spread out. Most lush feed is mainly water. This means stock need to eat a large volume to get enough energy. This is a big issue in twin-bearing ewes. Twins take up a lot of room in the abdomen, leaving only a small space for the rumen. It is essential that twin-bearing ewes are fed an energy-dense diet, so they can physically eat enough to supply the energy they need. Length of the feed is also important. Sheep can graze quite close to the ground, but cattle need a bit more length before they are able to eat it.

Metabolic issues

Another potential issue on lush green feed is a metabolic one. Grass tetany (magnesium deficiency) and milk fever (calcium deficiency) are common as the large amount of potassium present blocks absorption of these minerals.

One of the best ways to prevent issues in sheep is to provide a lick containing calcium and magnesium. A simple home-made lick for sheep can be made from 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 treatments containing these elements.

Vaccinate

Before putting your stock onto green feed, make sure their clostridial disease vaccination is up-to-date. This could be done using either 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. Previously vaccinated stock should get another booster if it has been more than six months since their last vaccination.

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 lamb just before they are able to top the local sale.

We always seem to lose more stock on green feed than when it is dry. By using some preventative measures now, you can ensure that green grass translates into green cash rather than green carcasses.