Supplementing yearling stocker cattle in late summer
August 25, 2014
Record high cattle prices and relatively low feed prices suggest that supplementation of grazing cattle may be economically feasible this year. There have been some recent columns suggesting that creep feeding should be considered, and I would like to address supplementation of yearling stocker cattle from now until they are pulled from pastures this fall.
The first question should be what type of feed would be best to provide? Particularly, would a less expensive, grain-based energy supplement work well, or should they be provided a protein supplement? As we progress through late summer and into fall, grass will become increasingly more mature with more stems and fewer leaves. This means it will have less soluble nutrients such as protein but more fiber and lignin. While fiber is digestible by rumen microbes and a good source of energy for ruminant animals, lignin is not digestible and it impedes digestion of fiber, protein and other nutrients. Thus, forage quality will be declining as time passes.
Typically, protein supplements provide the best response in low-quality forages such as crop residue or dormant winter range, but late summer grass is not that low in quality. In fact, whether a protein or energy supplement should be used depends on the year, and particularly the weather that summer. Research conducted many years ago at the KSU Hays Research Center in western Kansas indicated that grain-based energy supplements worked best in drought and near-normal precipitation years, but protein supplementation worked best in high-rainfall years. Presumably, with high rainfall and abundant plant growth, there is a large supply of digestible fiber and other carbohydrates for energy, but a relatively diluted supply of protein.
To further support this, John Moore, a now-retired beef cattle nutritionist, reviewed all research about supplementation of grazing cattle and concluded that supplementation with protein was most beneficial when the ratio of TDN:CP was greater than 7. For example, if late summer grass selected and consumed by cattle in a wet year has TDN (total digestible nutrients is a laboratory measure of energy content) of 57 and CP (crude protein) of 8, then the TDN:CP is 7.1. This suggests that a protein supplement should be recommended.
Much of the Tri-State Livestock News region has had a high-rainfall year, suggesting this is a year to use a protein supplement. This can be any feed that has more protein than the expected level in the grass. Because the grass being selected and consumed by grazing yearlings likely has a crude protein content in the 7.5 to 10 percent range, any feedstuff with protein content in the mid-teens or higher would make a viable protein supplement. Examples could include distiller's grains (e.g. DDGS), wheat midds, or oilseed meals, among others.
Those producers in the pockets of continuing drought throughout the region should probably consider grain-based energy supplements, assuming they have enough grass remaining to leave the stocker cattle on pasture.
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The next question to consider is how much supplement should be provided. In his review, John Moore recommended that any level of supplemental crude protein greater than 0.1 percent of animal body weight caused increased ADG in growing stocker cattle. To put this in perspective, three pounds of DDGS containing 30 percent CP fed daily to 700 pound yearlings would provide supplemental CP at 0.13 percent of body weight. Increasing levels of supplement appeared to directly improve ADG up to about 0.25 percent of body weight, with levels higher than that not providing additional improvement in ADG. In this example, 0.25 percent of body weight would be about 5.8 pounds of DDGS. On the average across all of the studies that Moore reviewed, this range of supplemental protein should lead to a range in additional ADG from one-half to one pound per day.
The final question to consider is the economic feasibility of supplementation, particularly now that I have recommended feeding more expensive protein feedstuffs. This is a great opportunity to use a partial budget, which is a tool to compare the economic value of two or more alternative management practices. Lets consider an example: grazing stocker cattle for an additional 45 days (mid-August to the end of September) with or without a protein supplement:
Without the supplement, lets assume we are working with 800 pound steers that will gain 1.4 pounds per day in August and September (based on performance of yearling steers I worked with in northern South Dakota last summer). That will lead to 63 pounds of additional gain and I will market 863 pound steers in early October. Ignoring shrink to keep this simple, the recent market suggests they would conservatively be worth $200 per cwt. for a steer value of $1,726. There will be no costs associated with not providing a supplement.
With supplementation, lets assume that providing 3 pounds of DDGS boosts ADG to 1.9 pounds per day. In this case, final steer weight would be 885 lb. Assuming no slide to keep things simple, the market value per steer would be $1,770. If DDGS, including the cost of delivery to the cattle, were $165 per ton, the cost for supplement for 45 days per steer would be $11.14, for a net value per steer of about $1,758. Thus, supplementation pays because the supplemented steers will have a net improvement in value of about $33 per steer.
We are living in amazing good times in the cattle business. They are worth record values and practically any wisely chosen management practice provides the opportunity to significantly increase their value.