Be Wary of Nutrition Levels and Downer Cows14 March 2013
CANADA – As the calving season approaches, farmers are being urged to monitor breeding herds being especially wary of Downer cows in the light of forage standards being different this year to typical winters.
The wet and cloudy summer of 2012 meant growth rates and quality was different and high quantities of cut grass had to be stood out longer.
Main concerns centre around protein and energy levels. Forage sampling has shown a 20-25 per cent drop in both protein and calorific content.
This means cows need a close eye on them this spring as heifer develop the maturing calf and require more nutritional intake, according to Barry Yaremcio, Beef Forage specialist at Alberta Ag Info centre.
He says the wet summer left greater amounts of Potassium mobilised in the soil to be taken up by plants.
“Instead of having typical 1.2-1.5 per cent Potassium level we are getting 2.5 – 3.5 per cent,” says Mr Yaremcio. “High potassium levels in forage reduce absorption of magnesium which can contribute to the increases in Downer cows.”
Calcium and magnesium deficiencies at this time of year are particularly troublesome as the herd approaches calving. Tissue building and bone development of the calf coincides with colostrum production 3-4 weeks before calving, adding to the energy demand on the mother cow.
“Limited calcium and magnesium from forage means cows will need to mobilise calcium from their own bones. This means there is a chance of getting Downer cows,” adds Mr Yaremcio.
Feed test results are therefore important to gauge forage quality and cattle requirements, although Mr Yaremcio adds that what is on paper may not equate to what the cows are actually eating.
Research at the Agriculture and Agrifood Canada Research Station, Lacombe used a bale processor and found that feed wastage can result in 25-30 per cent of calcium being lost out of that ration.
Mr Yaremcio stresses that magnesium losses can be at around 25 per cent, just because of fine leaf material being ground into the snow and lost.
“This means that a properly balanced ration with a 2:1 calcium to phosphorous ration could be narrowed down considerably with the wastage factor,” warns Mr Yaremcio.
He advises professional advice and diagnostics are required when an animal is suspected to be showing ‘Downer cow’ symptoms.
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