October 05, 2020

Interpretive Summary: Stocking rate, advancing season and supplemented DDGS in steers grazing in the northern Great Plains

Interpretive summary: Influence of stocking rate and advancing season on forage intake, digestibility and ruminal fermentation in steers supplemented with dried distillers grains with solubles while grazing northern Great Plains rangelands.

By: Dr. Emily Taylor

The number of animals per acre or live weight per acre is more commonly referred to as stocking rate. This management factor can have major impacts on animal performance, producer profitability, and long-term sustainability of native range-based ecosystems. As stocking rate increases, individual animal growth rates decline, usually due to the increased competition for preferred herbage. In addition, dietary chemical compositions of grazed forage when coupled with forage intake and digestion are important factors also impacting livestock performance. Therefore, the objectives of this study, published in Translational Animal Science, were to evaluate the effects of stocking rate and advancing season on diet chemical composition, intake, digestibility, and ruminal fermentation in steers supplemented with distillers grains with solubles while grazing northern Great Plains rangelands.

One hundred and eighty-eight steers were utilized to meet targeted stocking rates with 12 being ruminally cannulated and used for diet sampling. There were five 10-d collection periods from May through September. Steer body weight and average daily gain did not differ throughout the trial. Forage nutrient composition, intake, fermentation, and digestibility were influenced more by seasonal factors than stocking rate. As season advances, rangeland forages increase in fiber and decrease in N. Authors hypothesize that supplementing with DDGS may have mitigated the impact of stocking rate through forage substitution or improved forage digestibility if the forage had become limiting