Weather cut a harsh swath through winter feed supplies all across the country last month causing headaches for cattle producers who were scrambling to salvage what they could from the leavings.
In Alberta early snow covered many acres of annual crops grown for greenfeed, raising concerns that it may not dry before it had to be baled.
Bales containing 18-20 per cent moisture (or higher) have the potential to heat. Some of the sugars will be used by the microbes during heating, reducing the energy content available to the animals. If temperatures within the bale get above 40 C, the bales will smell sweet or like tobacco and the colour turns dark brown or black. When this happens, some of the protein will be tied to the fibre and not available to the animals.
Before you feed it request an acid detergent insoluble nitrogen (ADIN) or ADIP protein test in addition to the regular feed analysis. Use the lower adjusted protein value when formulating rations.
Moulds also arise in higher moisture bales, reducing quality and making the bales unpalatable. Don’t put mouldy bales through a processor. Better to roll them out so the cows can sort through it to find sound feed.
Nitrates are another issue in weathered greenfeed, especially in crops that were well fertilized or manured. Such crops cut three to five days after a light frost are ripe for nitrate accumulation. When the bales heat nitrates may be converted to nitrites which are 10 times more toxic to the animal. Heating may cause the bales to slump or lose their shape. This is a sign that you need to test for both nitrates and nitrites before letting the cattle at them.
Don’t stack higher-moisture bales in stacks or under a hay shed. If the bales start to heat, temperatures could get high enough to cause spontaneous combustion.
In Ontario an early dry spell cut into forage supplies sufficiently that people are looking for ways to stretch their winter feed supplies.
Forage and grazier specialist Thomas Ferguson offered a couple of suggestions.
Corn stover or straw are two obvious alternatives.
Corn stover can provide feed well into the fall and winter as half of the energy in a corn plant is in the stalk. Immediately after combining, corn stover may have a TDN as high as 70 per cent, however, as the season progresses and the cattle eat the more nutritious parts of the plants the TDN will drop into the 40s.
Strip grazing with an electric fence can slow down this slide by forcing them to clean up each section before they move on.
Generally when the husks and leaves have been stripped off the animals will require additional feed. One acre of corn stover can provide feed for one to two beef cows for a month.
Straw will supply much of the energy needed by mature dry cows in the second trimester but will need to be supplemented with a protein source. At this stage a diet of straw and quality hay, along with salt and mineral can provide all they need. As the nutritional needs pick up some grain supplementation will be needed.
Oat straw is the most nutritious, followed by barley, soybean and wheat.
The easiest way to incorporate straw into a diet is through the use of a TMR mixer to thoroughly mix the straw and the hay with any grain that is required, however, the feed needs to be managed to ensure that the animals are not sorting through to eat the high-quality feed first and leaving the straw until the bunks are almost empty. This can lead to acidosis in the greedy cows that get too much energy.
Feeding straw and hay in separate bale feeders doesn’t help. The cows simply eat the hay first and avoid the straw.
Then there’s grain. One kilogram of corn can replace two kilograms of hay in up to one-third of the ration. Barley has roughly 90 per cent of the energy value of corn while wheat is equal or slightly higher than corn.
Distillers grain has higher protein content than ground corn and can be an economical feed source.
“In most cases when feeding grain, cattle will be limit fed, they need to have enough bunk space so all of the cattle can eat at once, otherwise the dominant cows will consume more than their share, putting them at risk of acidosis, bloat and getting fat,” says Ferguson.
If more than two kilograms per days are being fed he suggests breaking it up into multiple feedings per day to prevent acidosis and grain overload.