Cow College offers strategies for feeding forage
CLINTONVILLE – During the 56th annual UW-Extension Cow College’s second session, Dr. John Goeser and Dr. Randy Shaver, from the UW-Madison Dairy Science Department, reviewed lab results from 2017 forage and grain, and offered strategies to help producers get the most milk from their feed.
Goeser, also Rock River Lab director of research and innovation, advised producers to pay attention to what’s happening globally and within their region, on class III beans, milk and corn and project out margins over 12 months.
“This will give you a better idea of the economic conditions within the dairy industry, and what things may look like over the next four quarters,” he said. “But the forecast through December is not real pretty.”
He noted that the challenges also present an opportunity to, “dig a little deeper and come up with some new management schemes or a different way to feed cows to be in a better position to meet expenses on a monthly basis, and hopefully limit the need to plow into your equity.”
Goeser advised producers to keep this in mind when considering nutrition and forage quality. “It has to make dollars and sense - we have to move the needle forward gaining 25 cents to $1 per cow per day.”
Monitor the cows
Goeser stressed the importance of checking how much of the TMR cows digest, and how much is left unused, illustrating with a TMR example of 50 pounds dry matter intake, 50% of which is carbohydrates, 25% fiber and 25% starch.
“For every pound of starch or fiber that a cow digests we can equate that to maybe two to three pounds of milk,” he pointed out.
He noted that 42% of fiber is digested, which is less digestive than 60% starch. “That’s why grain makes more milk,” he said.
“We have a lot of opportunities for digestible carbohydrates within the rumen, and part of that has to do with how you manage your feed on the farm, including particle size of corn silage. Four to five pounds of digestible starch, for example, could mean 10 - 12 pounds of milk.”
Stressing that fiber limits getting nutrients into cows because it’s carrying the least amount of energy per pound, Goeser said, “We need fiber in the diet to avoid acidosis, and maintain a healthy rumen, but we only want to put enough fiber in there for good health, but hopefully we can capture more energy from starch, protein, sugar and fat.”
Decrease fiber, increase starch
Goeser offers these management strategies to minimize the amount of fiber in our forages. “Harvest a little sooner, put up corn silage that not only is going to put on a decent ear but is also has high fat content.”
He reported that starchy feeds are contributing around 70% rumen starch availability on average. “I’d like to see us capture 80 - 85% from corn silage, and 70 - 75 from corn grain. We’ve been putting up higher starch corn silage the past couple of years. There’s been more grain in crops over the last couple of years.”
Starch digestibility on 2017 corn silage improved generally because fermentation, was a little bit better, according to Goeser. “However, corn grain, in terms of dry or high moisture, looks to be feeding a little bit tougher this year,” he said. “We need to be looking at maybe grinding the corn finer or letting it cook out longer, or even adding raw corn starch to get more fuel into the rumen.”
Goeser noted that new-crop corn is just not as digestible as old crop corn. “As that silage ferments it tends to feed better. Corn grain does the same thing.”
Sharing information gleaned from decades as a researcher and educator, Shaver offered some additional management strategies for increasing nutrition while keeping costs down.
He noted that currently there’s a shortage of A and E vitamins, and a corresponding price increase of three to six times. He suggested considering prioritizing feeding supplements, if necessary, for pre-fresh cows, pre-dryoff, fresh cows, early lactation and mid/late lactation.
Shaver recommended using multi-ration groupings to maintain milk yield and body condition by using digestible fiber from forages and byproducts.
He cited lower NDF, Lignin and uNDF, along with higher NDFD, starch and milk production as corn silage and legume silage quality indicators for high producing dairy herds.
Noting a trend to longer length of cut for corn silage of 26 - 30 mm, Shaver said that studies have not shown the total length of cut to have a significant effect on milk fat content or rumination activity.
He reported that new alfalfa varieties have 5 - 15% lower lignin and up to 15% greater ivNDFD.
According to Shaver, reduced lignin alfalfa varieties provide:
- A wider harvest window;
- Later harvest opportunities, with increased tonnage per cutting;
- Reduction in the number of cuttings, and;
- Improved forage quality.
Shaver also sees advantages for planting winter annuals. “While they can serve a valuable cover crop, they can also be a good source of forage for replacement heifers, dry cows and lactation rations,” he said.