As Greg Halich writes in his introduction to the Producer’s Guide to Pasture-Based Beef Finishing, “Bringing animals to a finishing weight on pasture in a reasonable time frame is no easy task, and requires a fundamental understanding of how beef cattle mature as well as understanding the capabilities and limitations of various forages.” In the first excerpt from the Guide, Greg provided solutions to one of the most common mistakes made – harvesting animals before they are actually finished. Last week, we added to our understanding of why grass finishing is especially difficult with research showing the two types of fat a cow’s body produces and how what it eats affects fat production. We learned that the marbling that provides important health benefits and is thus preferred by consumers, is reduced due to the fermentation pattern when animals consume grass or roughage.
You can improve marbling with good genetics and/or by allowing animals to get much older before harvest. But the more time you spend raising an animal, the more costly it becomes. With that in mind, Greg provides some reasons why a “grain-on-grass” production system may be a good option to meet customer preferences in an efficient, economical way. To help you look at how that might work, here is the second excerpt from the guide, with many thanks to Greg and his co-authors. (Please keep in mind that Greg was thinking of southern producers specifically, so you will need to adapt some of this information to your own regions and forages.)
Pure Forage vs. Grain-on-Grass
One of the most important production decisions to make with pasture-based finishing systems is whether to use a pure forage diet (pasture, hay, haylage, etc.) or to supplement with grain. The method chosen will have major implications on the remainder of the production process as well as with marketing. In general, grain supplementation will allow more flexibility in the production process and will make it easier to finish cattle. To get a finished and adequately marbled animal on a pure forage diet will require a higher degree of management. Also, it will typically take a longer period of time to finish an animal on a pure forage system as energy intake and gains will be lower. Which of these systems best fit your operation will depend on factors such as your target market, calving season, forage base, and desired finishing window, as well as your personal philosophy.
The grain-on-grass production process varies widely. Grain-on-grass systems as described in this publication assume that no more than half of total energy intake is from concentrates and that animals will at minimum be grazing pastures during periods of active vegetative growth. This process generally means 1.0 percent or less concentrate intake on a dry matter basis based on bodyweight. Typically, finishing cattle offered a high concentrate diet have an average total intake ranging from 2.25 to 2.75 percent of body weight on a dry matter basis. Higher grain feeding levels will for practical purposes more closely resemble a feedlot diet. However, there are some producers who grow calves on forage during the grazing season followed by 60 days or so of feeding a predominately high concentrate diet on their farm mimicking a conventional finishing system for a shortened time period. This type of system can work well for some producers if you have the corresponding market for it. This publication will focus on systems us- ing forage during the entire feeding period and will not cover conventional finishing systems.
With some grain-on-grass systems, a partial grain diet is fed continuously after weaning. In others, grain is fed only during the last few months before processing or during periods of low forage availability and quality. The goal of a good grain-on- grass system should be to optimize the forage resource while maintaining moderately high gains during inclement periods. The end result is a product with higher quality consistency compared to a pure forage diet for most producers. As tall fescue and other cool-season forage quality begins to decline in early summer, animal performance will also drop off. To maintain a high level of gain during the summer, you will need either energy supplementation or a high degree of forage management that does not rely on predominately fescue pastures.
The grain-on-grass approach allows for an easier transition to a finishing system for most producers compared to a pure forage approach. The use of concentrate feedstuffs and co-product feeds provides a mechanism to more consistently obtain the high rates of gain desired for finishing. The forage base and forage management can gradually be improved allowing for a transi- tion to an all-grass system if desired. Additionally, the use of concentrates arguably results in a more consistent end product in most situations, es- pecially during winter when animals are to be finished on stored feeds or during times of low pasture quality and/or availability. Table 1 highlights the broad differences between the two systems, including advantages and disadvantages.
Grain Supplementation during Grazing Season
There are several reasons to consider supplementation during the grazing season. Supplementation will improve animal performance when grazing endophyte-infected tall fescue by diluting the consumption of endophyte alkaloids and will also increase the energy level of the diet. Supplementation during July and August, when both forage quality and availability are low, is particularly helpful in the upper south in maintaining rates of gain necessary for finishing at this time with little to no reliance on alterna- tive forages such as summer annuals.
Those who want to market their beef under a certification system can start by reviewing the American Grassfed Association’s (AGA) system. The AGA has developed two protocol systems — grassfed and grass pastured. The grassfed protocol allows emergency use of supplementation up to 25 percent daily intake and 1 percent lifetime intake. The grass pastured protocol allows for 20 percent of daily intake during the growth stage and 30 percent of daily intake during the finishing stage. Both protocols have approved supplements. Since standards may have changed or been updated since the time of publication, go to the AGA’s standards page to get details of these certification systems.
Strategic supplementation during periods of low forage availability and quality will provide greater efficiency (more gain per unit of supplement) compared to year round supplementation. Table 4 shows expected increases in gains from .5 percent and 1.0 percent supplementation of common forage types in the upper south at various seasons. The information in this table can help determine realistic gains for a grain-on-grass system and how those gains relate to the required gains needed to reach the desired finishing window.
Providing supplement free-choice typically results in high rates of feed consumption (greater than 1.5% bodyweight) and low forage intakes. This system may be fine for some producers given their specific market. However, calling this type of production system “pasture-based” is debatable. Ultimately your market and customers will have to answer this question. Grain-on-grass supplementation in this publication is defined as focusing on managing forages for optimal quality and uti- lizing supplements only to maintain an adequate level of performance.
When considering which supplement to use in a pasture-based system, it is important to recognize that the animal’s rumen is naturally adapted to a forage-based diet and that the use of a high starch supplement should not be fed at high rates. Feeding high levels of a starch-based supplement will result in a rumen microflora shift, reduced ruminal pH (more acidic), and a decrease in the efficiency of forage digestion. Generally, it is recommended that not more than 3 pounds per 1,000 pounds (.3%) of body weight be offered of a high-starch feed such as corn, wheat, or barley to minimize the impact on fiber digestion. Fibrous co-products which are high in digestibility such as soybean hulls, corn gluten feed, wheat middlings, beet pulp, and dried distillers grains are supplements that will not negatively impact forage digestion.
The seasonality of forage quality and availability should be considered when developing a supplementation program for finishing cattle. For example, during the summer feeding rates of 1.0 percent of body weight may be required to achieve daily gains of 2.3 pounds (as a result of declining forage quality and heat stress) while feeding rates of .5 percent of body weight may achieve the same gain while grazing in the fall. If the focus is on optimizing forage utilization, the supplemen- tation program should be flexible to complement forage quality and availability. Typically, the greater the rate of supplementation the lower the efficiency of feed conversion. Producers should implement a for- age testing program and provide a supplement that achieves the nutritional requirements for the desired rate of performance.
There may be reasons to use strategic supplementation for finishing cattle other than improved performance. For example, during early spring when wild onions may limit the harvest window for some operations (due to off-flavored meat), the use of stored forages with supplementation provides a route to continue harvesting animals during this time frame. Another reason would be to allow for higher stocking rates on the pasture by supplementing during the summer.
In coming issues we’ll share more excerpts from this Guide covering pasture forage and grazing management. Stay tuned!