By Jason M. Warner
Short on pasture? Consider feeding a mixture of ethanol co-products with low-quality forage to replace grazed forage and increase stocking rate for cow-calf pairs grazing smooth brome pastures.
Locations in Nebraska where smooth brome dominated pastures are the primary resource for summer grazing is also where there is often readily available harvested cornstalk residue and ethanol co-products. These locations tend to be where pasture availability is limited. This research study examined feeding ethanol co-products mixed with low-quality forage to cow-calf pairs on smooth brome pasture to replace grazed forage.
This study occurred over a three year period at the Agricultural Research and Development Center located near Mead, Nebraska from 2011 – 2013. Pastures were grazed from early-May until mid-September annually. The study consisted of two treatments. The first treatment consisted of cow-calf pairs that were stocked to graze an estimated 3.82 animal unit month equivalents of forage per acre during the grazing season without any substitution feed provided (this is the recommended stocking rate for this location.) An animal unit month is equivalent to approximately 780 pounds of air dried forage.
The second treatment was double the recommended stocking rate at 7.63 animal unit month equivalents of forage demand per acre. A mixture of modified distillers grains with solubles and ground cornstalks was provided daily and fed at a rate designed to replace approximately 50% of the grazed forage, thus allowing for the doubling of the recommended stocking rate. The mixture consisted of 30% modified distillers grains with solubles and 70% ground cornstalks on a dry matter basis.
The cow-calf pairs fed the mix were provided 0.6% of their body weight on a dry matter basis daily at the start of the grazing season. Increasing levels of this feed mix were fed throughout the grazing season to account for declining forage quality/quantity, as well as the increasing consumption by the calf. Pairs were group-fed once a day in metal bunks that provided 3 feet of bunk space per pair.
1. There was no statistical difference in cow and calf body weight between the two treatments at the end of the grazing season, although there was a tendency for cows and calves receiving the feed mix to weigh more than cows and calves that were only grazing smooth brome pastures.
2. The pastures in this study received the same treatments for four consecutive years and little difference was observed visually in condition or residual forage at the end of the grazing season each year between treatments.
3. Supplemented pairs were provided on average 15.7 pounds on a dry matter basis of the feed mix per day. This was estimated to reduce their intake of grazed forage by approximately 37%. One pound of the feed mix replaced 0.94 pounds of grazed forage.
4. Feeding of a significant level of fibrous, low quality forage with the ethanol co-products is necessary to reduce dry matter intake of grazed forage. As shown in other studies, feeding only highly digestible ethanol co-products would likely not have resulted in the same “grass saving” effect.
Results from this study would indicate that feeding a combination of ethanol co-products mixed with low-quality forage to cow-calf pairs grazing smooth brome pasture at levels estimated to replace 50% of the diet can effectively replace grazed forage. This management practice provides the opportunity to increase the number of cow-calf pairs that can be placed in a smooth brome pasture for the summer grazing season by replacing a portion of grazed forage with fed feed.