Forage quality guidelines shared at dairy feeding day
Manitowoc — Dave LaCount would like dairy farmers to re-examine their practices on growing forage feeds such as corn silage and haylage by asking some fundamental questions as they plan for a new production year.
LaCount is a nutrition and technical services manager for Purina Animal Nutrition, which is a division of Land O'Lakes. He was a presenter at the Manitowoc County Forage Council's annual dairy cattle feeding day which was held at the Hochkammer dairy farm.
Two sets of questions that LaCount wishes dairy farmers would consider are whether corn silage is being grown to provide energy, starch, or forage in the dairy ration and whether the purpose of growing crops on a dairy farm is to produce hay, grain, or milk.
LaCount's answer is that everything — in terms of feed quality and nutritional traits — must be geared to milk production. While 80 pounds of milk per cow per day might be viewed as a good average, he stated that the new competitive standards are 100 pounds of milk instead along with a combined daily total of 6.5 pounds of butterfat and protein (6 pounds was the previous standard) because “butterfat contributes greatly to the milk check.”
For LaCount, the key to achieving those milk production goals is in the percentage of digestible fiber in the forage feeds, particularly in corn silage. In many cases, he suggested, this might require a discussion with one's agronomist or crop consultant who could well be focused instead on obtaining maximum yields in tons or bushels per acre.
Fiber is key
When evaluating the quality of corn silage, focus on the digestible fiber percentage rather than the percentage of starch because the latter can easily and economically be replaced at today's relatively low prices for grain corn, LaCount advised. He pointed out that the fiber digestibility declines as the dry matter percentage of the corn silage increases.
“Digestible fiber is where the game is at” because of how ruminants can convert the fiber to energy for supporting milk production, LaCount explained. “This allows the cow to use her biology to produce milk.”
“Ask why your agronomist thinks you grow corn silage,” LaCount continued. If necessary, convert to the goal of obtaining a high percentage of digestible fiber with changes in product selection and crop management, he indicated.
Corn silage traits
For that reason, the grain corn hybrids with “stay green” traits are probably not suitable for making corn silage because of a conflict between the moisture in the grain and the plant, LaCount remarked. He pointed out that as the corn ear dries there isn't an increase in starch but its digestibility is reduced.
Start to harvest corn for silage at 70 percent whole plant moisture for storage in bunker units, LaCount saud. Although it will reduce yield by 10 to 15 percent, he suggested a cutting height of up to 18 inches because this will increase the percentages of both fiber digestibility and starch in the corn silage while also decreasing both the moisture content and the nitrate levels in the silage. Leaving more of the lower portion of the stalk enables an earlier harvest and reduces the amount of lignin (non-digestible fiber) in the corn silage.
An alternative, with a few drawbacks, is to grown corn with the brown midrib traits for making corn silage, LaCount said. Its traits include higher digestibility for both fiber (less lignin) and starch although starch content is lower. The drawbacks are lower yields, potential lodging problems, and difficulty with staying alive until harvest time.
With both corn silage and haylage, LaCount challenged dairy farm growers in Wisconsin and the Upper Midwest to determine if they're producing high or just average quality feeds. If it's the latter, then it's probably not an advantage to be growing and harvesting them rather than buying the forage instead, he said.
For both haylage and corn silage, LaCount warned that “poor quality feed still feeds like poor quality feed even if you dilute it down.” Don't be tempted to feed a mix of 70/30 high and low quality haylage or a 75/25 mix of 30 and 40 percent dry matter corn silage, he warned.
Support milk production instead by considering buying 180 relative feed value hay for $180 per ton or “high quality hay” for $100 to $140 per ton at auction markets, LaCount advised. Instead of feeding low quality corn silage, look at buying corn gluten feed or soybean hulls for $120 to $125 per ton, he added.
To a question about grass species in a dairy cow ration, LaCount agreed that fiber digestibility is better than for alfalfa but pointed out that this is the only major advantage. He cited the seven- to 10-day difference in the maturity stages of grasses and alfalfa and recommended growing alfalfa and grasses in separate fields.
For haylage or dry hay, LaCount has a quality standard for giving a dairy cow the capability of producing a combined 7 pounds of butterfat and protein per day. That means providing alfalfa with a relative feed value or quality with a score of at least 175, taking five cuttings of alfalfa by Sept. 10, a corn silage blend of brown midrib with high digestibility fiber traditional varieties, inclusion of fine ground dry corn and the possible supplementation with high moisture shelled corn and snaplage, he said. “Start harvesting when the relative feed quality is 15 percent above your target.”
At the moment, many dairy farmers in western Wisconsin and Minnesota, along with a few elsewhere, are facing feeding challenges with the forages that they harvested in 2016, LaCount reported. He highlighted them under a series of “concerns with 2016 forages” in his presentation here.
Starting with haylage, LaCount said there is “no easy fix” for the low levels of feed value, forage quality, fiber digestibility, and energy stemming from difficult harvesting conditions. Because these are due mainly to late harvests, he urged cutting as soon as there is a promising weather window.
As potential solutions for the low quality (protein is not a major concern), LaCount listed obtaining higher quality haylage, reducing the portion of haylage in the ration, using corn silage as a replacement and adding byproducts such as soybean hulls or corn gluten feed to the ration.
A longer range concern that LaCount expressed about haylage is the portion of leaves being lost before the forage enters the chopper. Citing Land O'Lakes research in 2016 showing a 22 percent loss of leaves between cutting and ensiling, he calls on equipment suppliers, custom operators and farmers to be aware of this because leaves have a relative feed value of 400 while stems are only at 65.
Corn silage woes
As with haylage, harvesting difficulty led to corn silage that is too dry, low in fiber digestibility, high in starch locked in hard kernels, poorly packed in bunkers, and affected with fermentation problems, LaCount observed. Following a growing season during which corn plants were wet during a majority of hours on many days, corn silage is also exhibiting molds and toxicity — a concern well documented in corn silage samples tested at Rock River Lab from Oct. 1 to Nov. 18.
Solutions include feeding less corn silage, replacing it with soybean hulls or corn gluten feed, introducing more energy with supplements of molasses, starch or fats and checking the effectiveness of enzyme products for improving fiber and starch digestibility, LaCount said. “This might be the year to try enzymes.”
Delays in harvesting resulted in high moisture shelled corn and snaplage that is also too dry, LaCount pointed out. He finds this to be a frequent situation in eastern Wisconsin, resulting in corn kernels not being digested, less energy available to cows and lower butterfat content in milk.
Process the dry moisture grain corn in hammer mills with a small screen, feed some finely ground corn and add some molasses, corn starch and fat to the ration, LaCount said. He can be reached by email to firstname.lastname@example.org.