Letting cattle ‘pick and choose’ what they want to eat is no substitute for feed testing.
The quality of forage needs to be matched to the animal’s needs — and those nutrition requirements are going to change throughout the year.
And that’s why you should test your forages, say experts and groups such as the Beef Cattle Research Council.
“When feed grain prices are high, a high-quality forage can provide a lower-cost ration than a low-quality forage supplemented with a concentrate,” the council notes. “Failing to provide all the nutrition a cow needs due to low-quality forage can have animal health and performance consequences that directly impact cost of production including loss of body condition, dystocia, lower milk production, and delayed returning to estrous.”
Many factors — including the stage cut, fertilization, and grazing intensity — affect the ability of forage plants to provide digestible and absorbable nutrients.
That’s why forage testing is necessary, said Fito Zamudio Baca, forage and livestock program manager with the West Central Forage Association.
“It is the only way to accurately know feed quality — therefore assuring producers are meeting their herd’s different nutrition requirements the most economical way, and requiring less money to feed the cattle,” he said.
Testing should take place as close as possible to when the cattle are going to be eating the feed, and relying on old tests is a mistake, he said. That’s because rain and snow will cause nutrients to leach into the ground while moisture (either from when it was cut or improper storage) increases the odds of mycotoxins and mould being present.
“If we test last year’s feed and want to feed it this year, the feed is going to deteriorate,” he said. “If you rely upon last year’s results, I think you will be disappointed.”
How you sample the hay can also make a lot of difference.
“I do not recommend doing a ‘hand grab’ sample,” said Zamudio Baca.
A handful pulled out of just one bale means there won’t be a lot of leaf material (where the nutrients are stored) in the sample. As well, that method only produces a very small sampling of that hayfield.
Instead, use a hay probe.
“(With a hay probe) you can have a core sample, and sample 10 to 20 different bales. That will provide you with a more representative sample that will tell you more about the quality of the hay that you are going to feed.”
Samples should be put in large zip-top bags and labelled by field, especially if you are testing hay from more than one field. (Grouping bales by field will help ensure you know which bales correspond to which tests, Zamudio Baca noted.)
There are many labs to send the samples to, not only in Alberta, but across Canada. If you don’t have a nutritionist or someone to submit the tests to a lab on your behalf, talk to your local forage association, he added.
“It will have the forage probes and means to send it to a lab, and help you interpret the results.”
What to test for
Deciding what tests you want can also be challenging.
Many labs have their own specialized tests, or packages that group a number of tests together for certain types of animals. (For example, for dairy cows or horses.)
Zamudio Baca recommends checking for crude protein, dry matter, energy (total digestible nutrients/TDN or net energy of maintenance/NEm), neutral detergent fibre (NDF), acid detergent fibre (ADF), and relative feed value (RFV — which is more of an equation). In addition, minerals should also be tested in the sample. For cattle these are the calcium-to-phosphorus ratio, magnesium, and potassium.
Running a test for mycotoxins is a good idea if you are feeding high-moisture feed or hay from a previous year.
“If there are any doubts about the feed, we need to ask for a mycotoxin test on top of everything,” said Zamudio Baca. “If we spend another $25 on a mycotoxin test on each sample, but save five or six calves, then it pays for itself.”
The key numbers
Finally, you need to do more than glance at the results and then file them away.
“We need to check three to four things quickly on the feed results,” Zamudio Baca said.
Test results usually have two columns: ‘As Fed’ and ‘Dry Matter Basis.’ Focus on the dry matter basis, particularly the crude protein levels. A cow’s protein needs vary according to the production stage.
“Crude protein is a building block. The beef cow rule of thumb is 7-9-11. Seven per cent is good for mid-pregnancy, nine per cent is good for late pregnancy, and 11 per cent is good for after calving.”
Neutral detergent fibre (NDF) is another parameter to check on your feed tests.
“For high-quality feed, NDF has to be less than 40 per cent.”
Lastly, check for total digestible nutrients (TDN).
“We want to see a number less than 50 per cent,” said Zamudio Baca. “Those three are very crucial.”
When buying hay, relative feed value (RFV) is a quick way to assess quality.
“Quite often we don’t buy feed on quality, but focus on looks, smell, guessing the weight, and price,” he said. “With the RFV we can quickly determine what the quality of that feed is and pay accordingly.”
Once you know what you have in terms of quality, you can more accurately calculate how much you will need.
“We know a cow needs 2.5 per cent of her body weight of dry matter so you can calculate per head and for the whole herd,” said Zamudio Baca. “We need to also consider the environment and the waste and take that into consideration when you are going to feed the feed. Some waste can be up to 25 per cent.
“Once we quantify how much feed we need and we know the quality, the next step will be doing a ration.”
There are software programs available that will assist with ration balancing, he added.
But the bottom line is that forage testing boosts the bottom line.
“It costs between $20 and $50 for each sample (excluding mycotoxins). But the way I tell it to the producer is, ‘If you spend $100 a sample, save one or two calves, then you get more than double the money from that sample alone.’”