Straw became an important source of cattle feed this winter in areas of
Saskatchewan and Alberta hit by drought.
It can be an acceptable part of the feed ration for overwintering
cattle, as long as producers recognize its limitations.
When feeding straw, make sure the cattle are getting enough energy,
protein, vitamins and minerals.
Dale Engstrom, head of Alberta Agriculture’s beef, dairy and sheep
branch, said producers also need to be aware of the risk of impaction.
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Following is a checklist for producers who feed straw, especially those
with cows that will calve between now and spring.
Energy and protein
Cows won’t get as much energy and protein from straw as they will from
good quality hay. Pound for pound, straw typically has only half as
much protein as hay, Engstrom said.
Adding grain or a grain byproduct to the ration can increase the energy
in a straw-based diet.
Protein can be increased by adding feed such as canola meal,
high-quality alfalfa or lentil screenings.
There are also a number of commercial supplements available that will
add protein to the diet, along with vitamins, minerals and some energy.
Molasses-based supplements are best applied to straw bales, which helps
control the amount eaten by the cattle.
A lot of different treatments for straw are being marketed this winter,
with an emphasis on adding protein to the ration.
The emphasis on protein could result in energy content being
overlooked, cautioned Harry Brook, an Alberta Agriculture beef
specialist.
“If you’re using a protein supplement to increase intake, you can’t
ignore energy needs.”
Brook encouraged producers to do a feed test so they know what they’re
working with and what supplements are needed.
The amount of protein in straw can vary depending on the cereal it came
from. A feed test can help ensure enough protein is added to the feed
ration.
Knowing protein content might also save producers money, since they
will be less likely to exceed the amount of supplement required.
Vitamins and minerals
Engstrom said vitamin A and magnesium are two main concerns when
feeding a straw-based diet.
Cows with vitamin A deficiencies may give birth to weak calves with
weakened immune systems. In extreme cases, it may result in blind
calves or even blind cows.
Because cattle may not eat magnesium if it is offered free choice,
Engstrom said producers should add the supplement to the grain to make
it more palatable.
Impaction
This can happen when a cow eats more straw than its rumen can handle.
Microbes in the rumen can’t break down the straw fast enough and the
digestive tract plugs up.
Engstrom said the risk is greatest when cows eat more straw to
compensate for a severe temperature drop.
Feeding more grain during cold snaps can alleviate the risk of
impaction by providing more energy.
Engstrom said chopping or grinding the straw does not remove the risk
of impaction.
Age difference
The youngest and oldest cows in the herd will be among those most at
risk of poor nourishment when straw is the main feed. They may not be
able to compete against the more aggressive herd members when eating
supplements such as grain. Consider feeding them separately.
Body condition scoring
This can help determine whether cows are getting adequate nourishment.
It is done by feeling the fat over a cow’s short ribs and scoring the
condition on a scale of one to five.
“People new to straw feeding might be surprised at how fast their cows
lose condition,” Engstrom said.
A distended belly on a cow eating straw can make her look full and well
fed, even though she is undernourished and losing body condition.
Pregnancy
Be prepared to improve the diet during the cows’ third trimester of
pregnancy, said Alberta Agriculture beef specialist Delyn Jensen.
That means providing more better-quality hay or more of the supplements
that deliver protein and energy.
Boarding
Some Alberta producers who are short on feed are boarding their cattle
at feedlots for the winter, where a silage ration is typically included.
Engstrom said producers forced to buy hay this winter may find boarding
at a feedlot is just as affordable.
