Take precautions when feeding salvage crops to cattle

In drought years it’s often hard to locate adequate forage for cattle so producers sometimes turn to alternatives like drought-stressed pulse, oilseed or cereal crops that normally wouldn’t go for feed.

These emergency feeds can be a godsend in a dry year, but both Barry Yaremcio, a beef and forage specialist with Alberta Agriculture and Forestry and Dr. Bart Lardner with the Western Beef Development Centre and the University of Saskatchewan urge you to be mindful of the common pitfalls with salvage crops.

Nitrates

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“If you plan on using something like this, I recommend a feed analysis, to see what the protein and energy density might be, and some of the anti-quality factors that would make it not so good for livestock,” says Lardner.

“There might be a drought-stressed crop that is high in nitrates, for example.We often see nitrate accumulating in oats and other crops,” he explains.

In this case you need to figure out the level of nitrate in that crop, and how much, if any of it, can be safely fed.

“Generally the level is about 0.5 per cent nitrate in that crop, and so we have to dilute it when we feed it to cattle — to about one-third of the normal ration per day. If you know what you are dealing with you can dilute it down with some other feeds that are not high in nitrates,” says Lardner.

Producers in this situation for the first time often ask Yaremcio if they might reduce the nitrate content by 25 to 35 per cent by turning it into silage.

The research, he tells them, basically says that when the nitrate drops that much the quality of the silage will be bad, as well. You are better off to do a good job of packing and sealing to get proper fermentation, then double-check the nutrient content as the silage comes out of the pit. “Then if you have to deal with nitrates, you can modify your ration to adjust for nitrate content,” he explains.

Lost nutrient quality

Crops mature much quicker than normal in dry, hot conditions, so testing becomes very important with drought-stressed plants. Book values don’t mean much under these conditions as shown by some work Yaremcio did on 13 grass species near Edmonton in 1992-93. “We cut the stands every week, starting the first week of June, finishing in September. One year was normal, the other was a drought year. The loss of quality and drop in protein and energy content started about three weeks earlier than normal in the drought year,” says Yaremcio.

“The stands were a bit shorter, but looked normal. From the feed test results, the plants were losing 1.0 to 1.5 per cent protein and about five per cent energy per week after heading. The forage looked OK, but generally the quality was much lower in the drought year.

“If a person is cutting sloughs for hay, or old hayfields/pastures that haven’t been cut for several years, the quality of forage will be quite low, due to the old, dead material mixed in with the new growth. The quality could be as low as straw and should be treated similarly,” Yaremcio says.

Quality also becomes important when you are looking at using or purchasing some two-year-old hay. “When hay is stored outside, and not protected from weather, it will deteriorate. You may lose up to 25 per cent of the protein and 15 to 20 per cent of the energy. If it was baled at 14 per cent protein, you might have only 10 to 11 per cent protein two years later. You need to retest older forage before using it in a feeding program. Bale weight on large round bales may drop by at least 200 pounds, compared to when it was made,” he says.

“Some people have done digestibility studies on two-year-old hay, and found the digestibility is reduced about 10 per cent. The nutrient content on a feed test report may need to be discounted a bit because of the lower digestibility,” he says.

Larder says a number of people in his part of Saskatchewan have been putting up drought-stressed canola. Canola hay can be surprisingly good quality. It can also accumulate nitrates. So do a feed test, advises Larder.

Protein levels in canola cut at mid-pod stage average about 15 per cent, with energy around 60 per cent. When fully podded it is stemmy, usually with little or no leaf and may be down to 10 per cent protein and 50 per cent energy.

“It is less palatable than a typical grass/legume hay, adds Larder. “You have to make sure you build it into the diet at a blended level at something less than half the diet, and pay attention to minerals. Make sure the cows are on a good mineral program if you are looking at drought-stressed canola as a forage source,” he says.

“There are other crops out there that might work. One year we had a drought-stressed lentil crop, which is one that typically would not be utilized in a livestock feeding program. Since lentils are an annual legume, this crop might occasionally be another alternative. In the case we had, the lentils were not put up as hay, but simply grazed in the field by cattle. There can be some issues there as well, with certain levels of anti-quality factors, so do a feed test,” cautions Larder.

Whatever crop you are looking at his advice is to do a feed test and find out what you are dealing with first — and realize that in a drought situation the plants will tend to increase concentration of various constituents; they are not what you might normally expect.

Weeds

“One of the problems we’re facing right now is that some of the crops that did not germinate properly in the spring are full of weeds,” says Yaremcio. “Most weeds are not a problem and make good-quality forage or silage. But some commonly found in pastures such as water hemlock or seaside arrowgrass can contain toxins that kill animals. With forage in short supply, animals may graze areas that are usually avoided,” he says.

Other weeds are nitrate accumulators and may or may not be toxic. “Kochia and lamb’s quarters, for example, can have high levels of oxalates, which reduce the animal’s ability to use the calcium that’s present in those feeds. Silage or greenfeed containing a lot of weeds should not be fed at more than 50 per cent of the total ration.”

If you are not sure about certain weeds, have someone check them out for you and see what they are. A good source of information is the Canadian Poisonous Plants Information System website maintained by the Canadian government.

Lightweight grain

“One thing we’ll be faced with in some drought areas this year is a lot of lightweight grain,” says Yaremcio. Protein levels in drought-stressed grain will be different than normal just because the grain is lighter. Some work done in the mid-1980s at the University of Alberta by Dr. Gary Mathison tested barley that was 36, 48, and 54 pounds to the bushel. They found that feeding lightweight barley, at 36 pounds to the bushel, had a two per cent reduction in feed efficiency compared to 48-pound barley. For cows, and backgrounding rations, lighter-weight grain will work. If you have any questions, consult with someone who can help,” says Yaremcio.

Change gradually

When cattlemen have to feed non-traditional forages and supplements or concentrate feed like cereal grains, byproduct feeds or utilize drought-damaged forages, the important thing is to introduce the new feed gradually.

“If you are changing from a hay or greenfeed to canola silage, for example, include only about 25 per cent silage (dry matter basis), in the total ration for the first inclusion, says Yaremcio.

Keep it at that level for the first three or four days, to allow the animals to adjust to the different texture and taste. You will see a difference in the manure when going from a greenfeed to the canola silage. It will be looser — softer and wetter. If the manure is not watery and appears normal, it is safe to increase the silage to 50 per cent of the ration then up to whatever level your feed test tells you is safe. This allows for a gradual change in the population of rumen microbes so they can handle the new feed.

“When you increase the grain in a ration, it should be increased no more than one pound every second day. If you are changing from eight to 12 pounds, you need to take at least eight days to accomplish this. Again, watch the manure. If something is going wrong and the animals are experiencing acidosis or digestive upset, the manure will indicate there is a problem. If the manure gets loose when you are increasing the grain, reduce the amount being fed by about three pounds and let the cattle settle there for a week and then try increasing it again, no more than one pound every two days,” says Yaremcio.


Check the pellets too

Dr. Bart Lardner

Dr. Bart Lardner
photo: Supplied

“In a drought situation there is always a huge demand for pelleted products,” says Dr. Bart Larder of the Western Beef Development Centre. “Many producers are trying to build a ration that’s 50/50 straw-hay or a 50/50 straw greenfeed diet and then use a supplemental range pellet purchased from a feed mill. Those pellets usually consist of either barley or peas, with grain screenings added. The screening ingredients in those pellets might sometimes bring in the unwanted issue of a fusarium or ergot problem,” says Lardner.

When in doubt test, and with salvaged feedstuffs there is always doubt.

“We had calves on a research trial last winter and they were doing fantastic on the first load of pellets during the study. Then we brought in a new truckload and the calves went off feed. We sent test samples away to a lab and the report came back showing high levels of fusarium. When feeding drought-stressed crops, be alert to any unusual activity or signs of illness, or going off feed,” he says.

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