Feeding elevated levels of corn silage to reduce liver abscesses
By Erin Laborie
Liver abscesses are the main culprit for liver condemnation in finishing cattle. Feeding high-grain diets with little roughage can make the rumen environment more acidic and potentially cause damage to the rumen wall, which can expose bacteria to the bloodstream and lead to the development of liver abscesses.
Including an adequate amount of coarse roughage in the diet helps stimulate rumination and increases saliva production, which serves as a buffer in the rumen. Severe cases of liver abscesses can not only negatively impact cattle performance and carcass value, but also create concern for animal well-being.
The antimicrobial, tylosin, is often included in finishing diets to reduce the incidence of liver abscesses, which requires veterinary approval through a Veterinary Feed Directive (VFD). In an effort to reduce the use of antibiotics and need for a VFD, the University of Nebraska-Lincoln (UNL) conducted a study to determine if feeding higher levels of corn silage without the use of tylosin would decrease the prevalence of liver abscesses in finishing cattle.
In this study, cattle were fed 15 percent or 45 percent corn silage – on a dry matter basis –with or without tylosin.
Replacing up to 45 percent corn in the diet with corn silage resulted in lower daily gains, poorer feed conversions and required 28 more days on feed to reach a common backfat endpoint, but had greater final body weights compared to cattle fed 15 percent corn silage.
Liver abscesses were most prevalent – at 34.5 percent – in cattle fed 15 percent corn silage without tylosin and decreased to 19 percent when tylosin was included in the diet. However, increasing corn silage inclusion to 45 percent of the diet reduced the prevalence of liver abscesses to 12.4 percent, regardless of whether tylosin was fed.
Economic returns were greatest for cattle fed 45 percent corn silage without tylosin due to greater final body weights and lower ration cost. This increase in pounds sold and decrease in feed costs offset the increase in days on feed and poorer feed conversions for cattle fed higher levels of corn silage.
As the price of corn increases, it becomes more cost-effective to feed corn silage at higher inclusion levels. For example, cattle fed 45 percent corn silage returned $11.87 per head more than cattle fed 15 percent corn silage when corn was $3 per bushel and $40.64 per head more when corn was $5 per bushel.
Feeding elevated levels of corn silage in finishing diets can help reduce the incidence of liver abscesses without antibiotic use and can be an economical feeding option, especially for farmer feeders who can market their corn through their cattle.
Erin Laborie is a Beef Systems Extension educator at the University of Nebraska-Lincoln and is based in Beaver City, Neb. She can be reached at firstname.lastname@example.org.