Cheap corn could lead to more cases of acidosis.
By: Travis Meteer, University of Illinois
As farmers put together least-cost rations this winter, many of them will be using corn as an ingredient. For many farmers, corn stored on farm will be the cheapest source of energy. It has been a few years since corn has been this "cheap." Thus, it is worth reminding cattlemen of the dangers of acidosis when feeding higher levels of corn.
Acidosis is a nutritional disease that is caused by cattle consuming too much starch (primarily grain). Grains are rapidly fermentable in the rumen. Swift absorption of acids produced by that rapid fermentation leads to acidosis. Cattle consuming high grain rations, high sugar diets, or even cows grazing stalks that are host to too much ear drop or down corn could be victims of acidosis.
From a cow/calf and backgrounder perspective, the majority of the diet will be made up of hay or some other type of forage. In this case, supplementing the forage with corn (starch) can be beneficial to provide needed energy in the animal's diet. However, if the supplementation becomes higher than 0.5% of the animals body weight it could negatively affect fiber digestion. Poorer fiber digestion can start the shift in population of the bacteria in the rumen. Higher corn (starch) inclusion can quickly shift the bacteria populations and subsequently the pH. The pH lowers in the presence of higher starch and as a result the bacteria and protozoa that digest fiber greatly decrease in activity and quantity.
Corn processing can also be a contributing factor to acidosis. Corn that is ground too fine can cause issues due to the fermentation rate. Corn that is more powder than kernel will promote rapid fermentation, which can cause a quick shift in the bacteria and as a result the acidity.
Dried Distillers Grains (DDGS) are naturally acidic in nature. Sulfuric acid is part of the flush process in the co-product stream. As a result of this, sulfur levels are a good indicator of how low the pH is. More sulfur, the lower the pH in my experience. DDGS is also small in particle size and fairly rapidly fermented. These characteristics can lead to lower rumen pH despite the absence of starch.
Corn silage harvested in 2014 is likely containing more corn than ever before. Corn silage is extremely palatable and cows can easily overeat. This can pose similar problems to increased corn inclusion rates. If intakes are not limited on 2014 corn silage, it may very well contribute to acidosis.
I would lend caution to cattlemen and nutritionist that are enticed by the least-cost advantages of corn silage, corn, and DDGS. Acidosis can decrease performance, but more importantly can cause laminitis which can ruin hoof structure. Mistakes in nutrition that decrease the longevity of cows are simply not acceptable with high replacement costs we are experiencing today. Keeping cows currently in the herd productive should be a focus of profit-minded cattlemen. This can pose similar problems to increased corn inclusion rates.