Beef Cattle Performance on Three Forage Systems

Linda Benedict, Scaglia, Guillermo  |  11/12/2014 9:45:31 PM

Figure 1. Acres dedicated to each pasture type within forage system.

Figure 2. Schematic representation of the forage sequence for the different forage systems evaluated at the Iberia Research Station.

Figure 3. Average daily gains (pounds per day) of steers in different periods (summer, hay-feeding and winter) and overall (year-round) by forage system.

Steers on ryegrass, rye, clover mix pastures (March 2012)

No-till planting of sorghum-sudan (May 2011)

Pastures were rotationally stocked. Ryegrass, rye, clover mix (February 2012).

Steers on Tifton-85 bermudagrass (July 2012). Photos by Guillermo Scaglia

Guillermo Scaglia

Consumer interest in the benefits of forage-finished beef has led to an increased demand for this product and prompted the U.S. Department of Agriculture-Agricultural Marketing Service to define forage-fed beef. According to the 2007 Federal Register, forage-fed beef is considered such “when grass and forage are the feed source consumed for the lifetime of the ruminant animal, with the exception of milk consumed prior to weaning.” Additional labeling claims are usually made that forage-fed beef is produced without using growth promoters, ionophores – a type of antibiotic that improves gain efficiency – or sub-therapeutic antibiotics.

Based on this definition, the evaluation of three different year-round forage systems (Figure 1) began in May 2009 with the main objective of developing a feasible forage finishing program that would allow for the production of 1,100-pound steers at 17 to 19 months of age. This provided the opportunity to evaluate production systems differing in complexity that can result in an economic and sustainable alternative to produce forage-fed beef in the Gulf Coast region of the country. It should be emphasized that these are not the only forage systems possible in this region, which has weather that allows year-round grazing. Some challenges that the region faces are the heat and humidity of summer and the transition periods when summer and winter forages are not available.

Annually from June to May and for four consecutive years, 54 crossbred steers (25 percent Brahman influence) were assigned to one of three forage systems (three groups of six steers per system) a few days after weaning with an average weight of 550 pounds. The steers remained in their systems until harvest. The area dedicated to each system was 45 acres (15 acres for each group of six steers), so steers were stocked at 2.5 acres per steer. All pastures were rotationally stocked and grazed until a pre-determined forage stubble height, which differed depending on the forage grazed. It may appear that the number of acres per animal (stocking rate) is too high. However, in a year-round system the fluctuations of forage mass and nutritive value of the different forages limit the performance of animals. When defining annual stocking rates, these fluctuations must be considered as well as the animal’s nutritional requirements.

Excess forage in summer was harvested as hay and fed within the system when needed (Figure 2). Hay produced but not consumed was considered revenue for the system. Records of inputs and outputs were kept for economic evaluation of the forage systems. Figure 2 shows when the different pastures were grazed during the course of the year and the time and duration of the hay feeding period.

System 1 represented a very common system with bermudagrass for the summer, ryegrass for the winter and bermudagrass hay for the transition period. Ryegrass was no-tilled on bermudagrass sod (BG/RG) in a section of the system. Systems 2 and 3 should have had greater animal performance because there was an increase in forage mass production and quality, although management complexity and inputs used increased, too.

Systems 2 and 3 incorporated an area of dallisgrass – a high nutritive value summer grass – and a mix of white, red and berseem clovers for multiple-season grazing. In addition, the same clover mix and cereal rye were added to ryegrass for winter grazing. Since these clovers have a different growth pattern, determined through pasture measurement, they extended the time that, with some overlap, clovers are available. Berseem is available first, then red and, finally, white clover. Cereal rye provided forage mass earlier than annual ryegrass, but it was not enough to start the winter grazing period earlier.

System 3 was the most productive in terms of dry matter production and nutritive value because sorghum-sudangrass hybrid and forage soybeans (only difference to System 2) were added for summer grazing. This same area was planted with ryegrass for winter grazing (RG/SS and RG/SB) (Figure 1). The rest of the forages for System 3 were similar to System 2 (Figure 1).

Average daily gains of the steers in the different forage systems were similar across the systems regardless of the time of year (Figure 3). Even though the sorghum-sudangrass/soybeans area produced better-quality forage during summer in System 3, the period during summer when animals grazed that area was too short (45-60 days, depending on the year), and they spent the rest of the time on bermudagrass (Figure 2). Although gains were greater during that period, the overall gain for summer of steers in System 3 did not differ from the other two systems. It should be emphasized that steers were young (recently weaned, 8 to 9 months of age) when placed on summer pastures. Steers’ nutrient requirements are greater than bermudagrass or sorghum-sudangrass can provide, hence their small gains. Older steers (14 to 16 months old) could gain more on the same pastures. Because of the greater area dedicated to bermudagrass in System 1 (Figure 1), it was possible to extend the grazing season for this system, reducing the hay feeding period (Figure 2) and allowing a small weight gain while steers in Systems 2 and 3 with longer hay-feeding periods lost weight (Figure 3).

Overall, gains were very similar across forage systems allowing steers to reach the target final weight of 1,100 pounds. Under the conditions of the present project, complex and high-input year-round forage systems did not guarantee greater body weight gains. Partial improvements of performance provided during summer when steers grazed forages other than bermudagrass were offset by the shorter grazing season. Another key period is the time between when summer forages play out and before winter forages are ready to graze. This is the so-called transition or gap period, which is represented as the hay-feeding period. Better quality of the conserved forages used or other forages can be used to ameliorate the negative effect of this period on animal performance. In the following articles, researchers will present additional information concerning the economics of these systems, carcass characteristics of the steers, meat quality, properties and consumer evaluation of the meat produced, marketing possibilities, and producers’ attitudes toward forage-fed beef.

Guillermo Scaglia is an associate professor at the Iberia Research Station in Jeanerette.

This article was published in the fall 2014 issue of Louisiana Agriculture.

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