This article was originally featured in the Wyoming Livestock Roundup.
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 creates 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 conducted a study to determine if feeding greater concentrations 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% or 45% corn silage (dry matter basis), with or without tylosin.
Replacing up to 45% 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% corn silage. Liver abscesses were most prevalent (34.5%) in cattle fed 15% corn silage without tylosin and decreased to 19% when tylosin was included in the diet. However, increasing corn silage inclusion to 45% of the diet reduced the prevalence of liver abscesses to 12.4% regardless of whether tylosin was fed.
Economic returns were greatest for cattle fed 45% 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 corn price increases, it becomes more cost-effective to feed corn silage at higher concentrations. For example, cattle fed 45% corn silage returned $11.87 per head more than cattle fed 15% corn silage when corn was $3.00/bu and $40.64 per head more when corn was $5.00/bu.
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.
For more information, see the 2021 Nebraska Beef Cattle Reports: https://go.unl.edu/silage-liver-abscesses and https://go.unl.edu/silage-economics.
This research was funded in part by the Iowa Beef Industry Council.
Interviews with the authors of BeefWatch newsletter articles become available throughout the month of publication and are accessible at https://go.unl.edu/podcast.
