With winter resulting in substantial winterkill and a wet spring delaying harvests, a lot of high-quality forage has been turned into, at best, heifer feed. There is justified concern about forage inventory and the need for high-quality forage.
In a Buckeye Dairy News article, Bill Weiss, an extension dairy specialist for The Ohio State University, says, “Although the current situation is not ideal, several options exist that will stretch forage inventory and allow inclusion of lower quality forages without substantial negative effects on milk yields.”
As a first step, Weiss suggests taking an inventory of your corn silage and determining if it is possible to raise feeding rates without depleting supplies before the new crop is harvested. If this is an option, bump up your corn silage-feeding rate and reduce the concentration of low-quality forage. When changing the feeding rate, try to keep the concentration of forage neutral detergent fiber (NDF) around 20 percent of the dry matter (DM).
Weiss also advises using supplements to balance out the change in forage. “Diets will likely need more supplemental protein since alfalfa and rye contain more protein than corn silage,” he says. “Cows may also benefit from increased supplementation of potassium and/or sodium buffers.”
The dairy specialist notes that it’s still possible to include lower quality forage in the feed ration. Remember, however, to keep the concentration of forage NDF below 20 percent of the dietary DM. Doing so does not eliminate the negative effect of the low-quality forage intake, but it will soften the blow.
The percentage of forage in the diet will be lowered since more mature forages have higher concentrations of NDF. While this may cause concerns about a reduction in milkfat yields, Weiss explains, “The amount of forage fiber, not total fiber, is what is important in respect to milkfat. Reducing the amount of forage in the diet means that inclusion rates of other feeds must increase.”
He recommends keeping dietary starch concentrations around 25 percent when replacing forage with corn. If starch concentrations are an issue, replace forage with by-products such as wheat midds, soyhulls, and brewers or distillers grains.
Depending on cow responses, another option is to replace your normal forage with whole cottonseed. It has an NDF concentration of 40 percent, which is similar to average alfalfa and, according to Weiss, replacing 8 pounds of alfalfa silage or hay DM with 8 pounds of whole cottonseed would have little effect on the cow.
Grow more forage
If your overall forage inventory is not enough to last until the end of summer, there are options for growing more forage. Weiss recommends brown midrib (BMR) summer annuals.
Brown midrib annuals, such as BMR sorghum, BMR sorghum-sudan, and BMR sudangrass, can be planted in early June when the soil temperatures are at least 60°F to 65°F. These annuals can be harvested within 60 days of planting and nutritionally are almost as good as corn silage. According to Weiss, these summer annuals’ NDF digestibility (NDFD) is also good, and their inclusion rates can be high.
Weiss concludes that the key is to limit forage fiber in the diet when feeding low-quality forage. He says, “Because lower quality forages are high in fiber, diets will contain less forage and more concentrate than normal, which will likely increase ration costs. But feeding too much low-quality forage will reduce milk yields, which is worse than higher feed costs.”