*Andrea Watson, Galen Erickson, Terry Klopfenstein and Jim MacDonald are with the department of animal science at the University of Nebraska-Lincoln. To expedite answers to questions concerning this column, please direct inquiries to Feedstuffs, Bottom Line of Nutrition, 7900 International Dr., Suite 650, Bloomington, Minn. 55425, or email [email protected].

WEANED calves backgrounded on cool-season pastures have metabolizable protein (MP) requirements that are greater than the forage alone.

The crude protein content of smooth bromegrass can be as high as 18% in the early spring, when the forage is rapidly growing. Throughout the summer, the protein content decreases as the forage matures. If temperature and rainfall are adequate in the fall, there will be regrowth of smooth brome with an elevated crude protein content.

The rumen undegradable protein portion that contributes to MP follows a similar pattern throughout the summer, but digestible rumen undegradable protein is fairly constant at 5-7% of crude protein (Buckner et al., 2013).

Supplementing calves with dried distillers grains plus solubles (DDGS) provides both rumen undegradable protein and energy in the form of fat and highly digestible fiber, which have been shown to improve average daily gain.

Excess nitrogen supplied to the cattle through DDGS is excreted in the urine as urea. This urea is quickly broken down in the soil and utilized by plants, resulting in greater forage production. Rotating cattle among pastures during the growing season ensures a more even application of this nitrogen on pastures. Supplementing the cattle with DDGS also offsets forage intake, allowing for greater stocking rates.

A 10-year study (2005-14) conducted at the University of Nebraska's Agricultural Research & Development Center near Mead, Neb., evaluated three grazing strategies:

1. Pastures were fertilized in the spring with 80 lb. of nitrogen per acre and stocked at four animal unit months (AUM) per acre.

2. Pastures were not fertilized, and calves were supplemented daily with DDGS at 0.6% of their bodyweight and stocked at four AUM per acre.

3. Control pastures were not fertilized but were stocked at 2.8 AUM per acre, and cattle were not supplemented.

Cattle had an initial bodyweight of 708 lb. and grazed from late April until late September (approximately 150 days) each year. Each group of cattle was rotated through six pastures, with cattle rotated after four days of grazing at the beginning of the growing season and after six days of grazing for the remainder of the season. There were three replications of each treatment every year for 10 years.

Cattle supplemented with DDGS gained 0.68 lb. per day more than either of the non-supplemented treatments, which led to an additional 100 lb. of liveweight at the end of the grazing season (Table). Cattle on both non-supplemented treatments had similar gains throughout the grazing period, but fertilized pastures had greater production per land unit.

Pastures stocked with supplemented cattle had similar production per land unit as fertilized pastures. This was due to both decreased forage intake and increased forage production.

In 2009 (midway through the 10-year trial), forage production was measured, and forage intake was estimated assuming 42% utilization of available forage.

The pastures stocked with supplemented cattle produced 650 lb. per acre more forage than the control pastures. A 70% forage savings was calculated, meaning that for every 1 lb. of DDGS, supplemented cattle consumed 0.70 lb. less forage (Watson et al., 2012). Other research has suggested that this can vary from 20% to 50%, increasing as the amount of supplement fed increases (Griffin et al., 2012).

Providing DDGS to steers also improved nitrogen use efficiency by 144% relative to the fertilized pastures (Greenquist et al., 2011). This was due to a 42% decrease in overall nitrogen inputs compared to the fertilized treatment, supplemented animals retaining more nitrogen (greater gains) and the increased stocking rate of these pastures relative to the control treatment.

Furthermore, supplying nitrogen through the animals with DDGS supplementation provided pastures with some resistance to annual weeds compared to the control pastures (Guretzky et al., 2013).

Economics

From 2004 to 2008, there was a large increase in ethanol production, and DDGS started being priced relative to corn; however, before that time and again very recently, DDGS increased in price. Throughout the 10 years of this study, supplemented cattle received 800 lb. of DDGS per calf, on average.

In a scenario with $3/bu. corn, if DDGS costs 95% of the price of corn, it results in a cost of $48 per animal for the supplement, but if DDGS costs 115% of the price of corn, the cost is $58 per animal. If corn prices reach $5/bu., it results in a cost of $80 or $96 per animal for DDGS at the 95% or 115% rate, respectively.

In comparison, it takes approximately 190 lb. of urea per animal to apply 80 lb. of nitrogen per acre. Using a price of $430 per ton with an application fee of $4 per acre results in a cost of $45 per animal to fertilize pastures with urea.

The economics of utilizing fertilizer or DDGS depends on the price of grass, the price of the nitrogen fertilizer and the price of the DDGS. The price of grass has been steadily increasing over the past few years. In Nebraska, the average 2014 rental rate was $40 per month for a 700 lb. stocker animal (Jansen and Wilson, 2014).

Paying $596 per ton for urea results in the same cost of gain for the fertilized and unfertilized (control) treatments; this is a ratio of 14.9 for fertilizer cost to grass cost. Therefore, if urea is less expensive than $596 per ton, it would be economical to apply fertilizer. Conversely, if the fertilizer is more expensive than $596 per ton, it would be more economical to use a lower stocking rate on more acres.

The ratio of DDGS to grass price, to give equal cost of gain, was 8.0. Therefore, if grass costs $40 for each animal to graze for one month, a producer could pay up to $320 per ton for DDGS. The ratio of fertilizer to DDGS was 1.53. If urea fertilizer costs $430 per ton applied, then it would be more profitable to feed DDGS if it could be delivered to the cattle for less than $281 per ton of dry matter.

The Bottom Line

Supplementing calves being backgrounded on bromegrass pastures with DDGS provides both protein and energy to the animal. More specifically, it provides bypass protein to meet the calves' MP needs, allowing for greater gains on pasture.

Pastures also benefit from the protein in DDGS, as excess nitrogen is excreted as urea. This, combined with a 0.7 lb. decrease in forage intake for every pound of DDGS consumed, allows calves to be stocked at the same rate as pastures receiving 80 lb. of nitrogen per acre.

In most scenarios, supplementing with DDGS is more profitable than fertilizing or stocking at lower rates; however, this is not a common practice, at least in Nebraska. The prices of DDGS, fertilizer and grass — and their relation to each other — are all factors that have to be considered when developing a grazing management plan.

Moderately priced feed and high-priced calves today are encouraging producers to beef up weights with summer supplementation. However, feedlots are also willing to pay a lot for those calves that would typically go to pasture for the summer, keeping margins tight.

This research will be presented at the national American Society of Animal Science meeting in Orlando, Fla., in July (Welchons et al., 2015).

References

Buckner, C.D., T.J. Klopfenstein, K.M. Rolfe, W.A. Griffin, M.J. Lamothe, A.K. Watson, J.C. MacDonald, W.H. Schacht and P. Schroeder. 2013. Ruminally undegradable protein content and digestibility for forages using the mobile bag in situ technique. J. Anim. Sci. 91:2812-2822.

Greenquist, M.A., A.K. Schwarz, T.J. Klopfenstein, W.H. Schacht, G.E. Erickson, K.J. Vander Pol, M.K. Luebbe, K.R. Brink and L.B. Baleseng. 2011. Effects of nitrogen fertilization and dried distillers grains supplementation: Nitrogen use efficiency. J. Anim. Sci. 89:1146-1152.

Griffin, W.A., V.R. Bremer, T.J. Klopfenstein, L.A. Stalker, L.W. Lomas, J.L. Moyer and G.E. Erickson. 2012. A meta-analysis evaluation of supplementing dried distillers grains plus solubles to cattle consuming forage-based diets. Prof. Anim. Sci. 28:306-312.

Guretzky, J.A., W. Schacht, L. Snell, J. Soper, S. Moore, A. Watson and T. Klopfenstein. 2013. Nitrogen input effects on herbage accumulation and presence of pasture plant species. Agron. J. 105:915-921.

Jansen, J., and R. Wilson. 2014. Nebraska farm real estate market highlights 2013-2014. Department of agricultural economics, University of Nebraska-Lincoln.

Watson, A.K., T.J. Klopfenstein, W.H. Schacht, G.E. Erickson, D.R. Mark, M.K. Luebbe, K.R. Brink and M.A. Greenquist. 2012. Smooth bromegrass pasture beef growing systems: Fertilization strategies and economic analysis. Prof. Anim. Sci. 28:443-451.

Welchons, C.A., T.J. Klopfenstein, J.C. MacDonald, A.K. Watson and R.G. Bondurant. 2015. Performance and economics of supplementing calves with distillers grains or fertilization of smooth bromegrass pastures. Proceedings of American Society of Animal Science national meetings, abstract 341.

Volume:87 Issue:23