Animal Nutrition

Winter feeding starts with a sample

A protein test on a randomly grabbed sample will be three to four percent lower than what the cattle are actually eating

Don’t grab randomly.

That’s good advice in social situations and it’s just as good when taking a forage sample.

Winter is approaching and cow-calf producers who plan to winter graze should take forage samples and make their plans, said livestock grazing guru Jim Gerrish.

But rather than taking a random sample from a square foot or square yard, for example, he advises grazers to take an “imitation grab sample” that will provide a more accurate assessment of feed value.

Go out to the pasture and watch how the animals graze, he said. Then do your best to collect the parts of the plants that the cows are actually eating.

“The animal is almost always going to be selecting a higher quality diet than what our sample tells us,” Gerrish said during a Sept. 30 webinar organized by Maia Grazing. “If you take the entire plant that’s standing out in the field and cut it down at ground level and get an analysis on that, that tells you nothing about what the animals are really eating.”

His experience indicates a protein test on a randomly grabbed sample will be three to four percent lower than what the cattle are actually ingesting.

Crude protein content and dry matter digestibility are the two key elements to consider for winter grazing. Though dry, brown grass may not look like it has much feed value, cattle will extract nutrition.

“As long as we have an animal with a properly functioning rumen, they can digest a lot of that fibre and extract energy from it,” said Gerrish.

“A lot of people think that brown grass that has been frost bit, that’s left standing at… the end of the season, they automatically think ‘well that’s no good.’ The reality is it really depends what species we’re dealing with and how that particular pasture had been utilized over the course of the growing season.”

Protein supplements may be necessary for cows in winter, depending on what sample testing reveals. However, supplements might not be needed every day. Ruminants are “batch processors,” Gerrish said. In dormant feed of the type eaten on winter pasture, it can take more than two days for material to pass through a cow.

Supplementing every third day can thus be sufficient and less costly.

Strip grazing is also an excellent tool to manage winter grazing, said Gerrish.

When turning animals into an open field, cattle seek out and eat high protein plants first and then are forced to eat the remaining stems that have low digestibility. That leads to reduced body condition unless supplements are provided.

Strip grazing allows ranchers to ration the available protein in the forage and manage rumen function. By matching the strip-grazing period to the rumen rate of passage, about 36 to 72 hours, animal nutrition can be maintained with less time and labour.

“This is what strip grazing does for you,” said Gerrish.

“It preserves winter feed supply deep into the winter because animals aren’t walking back and forth across it, trampling it down, pooping on it, wasting it. It preserves forage quality deeper into the winter. It improves animal condition deeper into the winter because they have more feed, better feed and that raises the overall performance of your livestock.”

Strip grazing has more value in winter than it does in summer, he added. If cattle can graze longer at higher quality, it limits the need and cost of supplying hay for an extended period.

“Planning for your winter grazing needs to start before the first blade of grass appears in the spring,” he added. A stocking plan, cattle flow plan and forage inventory are needed to make it successful.

“When we come to the end of the growing season, take an inventory at that time. That pretty well tells us what we’re going to have to work with,” he said.

Yes, the forage will deteriorate due to weather but it’s generally not as much as most people assume.

“Underestimate your forage supply and overestimate your demand,” said Gerrish. “That is a real important concept.”