Spring and summer arrive and most producers get a little glassy-eyed over the prospects of lush grass and low or non-existent feed bills. In most cases both cows and growing calves are suitably supplied with many of the various nutrients, especially protein, during this time of the year. While the Good Lord designed the cow to take advantage of grasses and forages and to make use of materials that other animals cannot, in many cases, we've learned that to optimize production, we may have to embellish a bit on what the animal can obtain from the pasture and/or hay that it might be on.
Research and practice has shown us that it is often advantageous to supplement pasture with grain or other feedstuffs to match pasture quality with animal requirements and to obtain higher gains on pasture. Obviously the primary objective here is that grazing animals are ready for market in the fall or soon thereafter. Supplementary grain feeding on pasture can increase daily gain 0.7 to 1.0 lb or more and cause cattle to reach a desired weight 60 to 80 days sooner. In many cases producers may offer grain on a free-choice basis or as has become more popular, grain intake can be restricted. Generally, cattle make more efficient use of grain and pasture when grain or other feed intake is limited. Other supplemental feedstuffs which can be fed on pasture include roughage such as hay, silage as well as a host of by-products and commodities available (i.e. soy hulls, corn hominy, corn gluten feed, etc.).
Level of Grain Intake
When grain is fed free choice to yearlings on pasture, grain intake will increase with decreasing forage availability and quality. Research from Western Canada suggests that on
well managed pastures, yearlings self-fed grain with no limitation, on pasture will consume about 1.5 lbs. of grain daily per 100 lbs body weight. This means a 825 lb animal will consume about 12.4 lb of grain daily, given free access. One recent study showed that the daily gain of grazing steers was increased from 1.8 to 2.7 lb daily when rolled barley was fed on a free-choice basis to steers on a brome-alfalfa pasture. The intake of grain on this study was to 1.55 percent of body weight. For most pastures, grain intake would be restricted from 0.8 to 1.0 lb of grain per 100 lb body weight for cattle that will be finished out. For very lush pasture or for selling feeders at the end of the grazing season, feeding 0.5 lb of grain per 100 lb body weight would be suitable. When pasture is limited and of low quality, such as late in the season, full feeding of grain is suitable although this must be performed carefully and with much attention to cost effectiveness.
One trial with steers utilizing excellent pasture had daily gains averaging 2.6 lb for the no grain group versus 3.27 lb for the group limit fed 7.0 lb of grain daily on pasture. These groups were compared to a third group in dry-lot fed twice as much grain as the pasture group plus dry roughage for an equivalent gain of 3.3 lb per day. In yet another study, workers found the daily gains of grazing yearling cattle increased from 2.5 to 2.9 lbs. when supplemental grain was fed on mixed pastures. The steers were hand fed, gradually increasing amounts of grain during July and August, and were only self-fed for one month. The feeding of grain also allowed stocking rates to increase from 1.06 to 1.36 steers per acre and increased total gains from 244 to 403 lbs. per acre. Obviously it is advantageous in this manner to increase the pounds of beef produced per acre of land.
Limiting Grain Intake
As we discussed last week, in many cases it is very important to control feed or supplement intake in some manner or another. Limiting grain intake can be accomplished by hand feeding daily or by self-feeding grain to which salt, fat, ground roughage or other limiting agents have been added. Self feeders are commonly used because they reduce the amount of labor, time and bunk space required and they allow cattle to eat at their leisure. Another benefit an appropriately designed self-limiting supplement can provide is an increase in the number of “meals” cattle consume over a given day. Instead of one or two large meals or feedings, cattle will eat smaller amounts each time they come back to the feeder and will come back more often over the course of the day. More about this in a bit. In all cases, yearlings must become accustomed to grain in their diet. In every situation when a supplementation or feeding program is initiated, it is wise to use an adjustment period of several days of feeding low levels of grain to help the animal adjust to the dietary change.
When salt is added to grain to restrict grain intake, the amount of salt needed will depend upon the level of feed intake desired, the size of cattle, the availability and palatability of pasture and the quality of water present. Cattle will become accustomed to high salt intakes and increase consumption of the self limiting feed. The following Table 1 provides a guideline in assessing the level of salt to add.
Coarsely ground salt is more effective in limiting feed intake than finely ground salt. Use plain white salt rather than the trace mineral or cobalt-iodized salt. The latter types of salt sources are more expensive and can lead to trace mineral imbalances. The grains should be rolled or coarsely ground to prevent separation of the salt from the grain. Pelleting the feed will also prevent separation but cattle may over eat salt limiting grain mixes that are pelleted. Cattle that are not accustomed to self-feeding should be introduced to the ration at a high level of salt such as 40 percent, then reduced to the desired level of intake to avoid overconsumption.
There are some things that need to be considered, however. Cattle have a high tolerance to salt but salt toxicity can occur within 8 to 12 hours on high salt rations if water is not present or is of poor quality. Good quality water is required to flush the salt from the animal's system. Yearlings fed self-limiting rations can be expected to consume an additional 50-75 percent more water than normal, or an additional 18 to 23 four to five gallons of water per pound of salt intake.
Additionally, salt limiting mixes are not fool-proof. Cattle can become adapted to the higher salt levels and maintaining intake control can be difficult. Additionally, use of high salt inclusive supplements in self feeders is corrosive and will reduce the life of metal self feeders. It is advised that if you plan to use a salt mix in your metal self feeders, they need to be cleaned and washed thoroughly every few months. Also, clean the areas where rusting begins and apply a coat of rust protectant to reduce metal degeneration.
A second method of self-limiting grain on pasture can be achieved with stabilized animal fat (non-ruminant sources such as pork or poultry fats as well as fish oils), by itself or in combination with salt. Fat at the four to five percent level has been used in feedlot rations to increase energy intake. However, when fat levels exceed 5 percent of the ration, consumption is decreased. In one study, researchers added 10 percent tallow to a rolled grain supplement and fed this combination to yearling steers on a mixed pasture of grass and legumes. They reported a 15 percent reduction in grain intake from 1.55 percent to 1.3 percent of body weight. Even though grain intake was reduced, average daily gains were maintained at approximately 2.7 lbs. per head per day. In the same experiment, the addition of seven percent salt to the supplement reduced intake from 1.55 percent to one percent of body weight resulting in an average daily gain of 2.4 lb. In still other studies, workers have found that the addition of seven percent salt or seven percent salt plus three percent fat, to ground wheat reduced the grain intake of heifers from one percent to 0.8 percent of body weight when compared with free-choice feeding of grain without the added limiting agents. Daily gains were similar even though grain intake was approximately 20 percent less with the fat-salt or salt limiting ration than the wheat alone. The researchers proposed that the wheat with salt resulted in greater forage consumption.
There are several advantages to using stabilized fat in self-limiting rations. They include:
*A higher energy content of the grain mixture.
*Reduced dust and reduced loss of feed through dustiness and sifting.
*Increased stability of vitamins and carotene if feed is pelleted.
*Improved feed conversions.
*Reduced settling of ingredients.
*Reduced incidence of frothy bloat.
Another method of limiting intake has been addition of coarse roughages to grain. This method relies on palatability and bulk rumen capacity to limit intake. From field experience, it appears that a 50 percent grain, 50 percent roughage mix will limit grain intake to approximately 5.5 lb for an animal weighing around 800 lbs. However, the animal has eaten 5.5 lb of coarse roughage to obtain the grain. As a result there is only a minimal increase in dietary energy concentration. That is, the animal could have consumed 1.1 lb of a mixed pasture and received a similar amount of energy and a lot more protein. This method could be used to decrease grazing intensity by providing more dry matter than pasture alone and may be useful in situations where pastures may be short due to drought or other environmental conditions. It needs to be recognized that increased animal gains will be minimal since nutrient intake, primarily energy will be limited.
Other methods of intake limitation include the addition of products such as fishmeal or anionic salts which effect palatability (another effect of the feeding of fats) and reduce the amount of time cattle will stand at the feeder and eat. As mentioned before the result here is that cattle will eat larger numbers of smaller meals at the self feeder. This spreads out grain intake through the course of the day and reduces the effect that consumption of large amounts of grain or supplement may have on the rumen environment. Remember that when we introduce larger amounts of grains (i.e. starch) to the rumen, the effect is that it reduces ruminal pH. This has a negative effect on the rumen bacteria that digest roughages. Subsequently this reduces the amount of roughage (pasture, hay) cattle can consume in a day. When this occurs, supplementation can actually have a negative effect on gains. This same effect is noted when producers hand feed supplements once per day or once every few days. Cattle consume larger amounts of grains and will seriously reduce fiber digestion for a period of time. This should be avoided at all costs.
By using limiting agents such as noted above to reduce meal size but increase feeding frequency reduce this negative effect on ruminal pH and in fact can improve forage intake and digestion by providing protein and energy to the ruminal bacteria in an effective form without creating a detrimental environment. This has been successfully accomplished not only with grain supplements but with liquid feeds as well although liquids will address protein supplementation more successfully than providing for energy deficiencies in many cases. Remember that the producers primary goals is to maximize the use of his forage source and only “fill the holes” in the animal's diet to maximize performance. In many cases this simply requires increasing the extent to which cattle consume and digest existing roughages.
Properly designed supplement and supplement programs can go a long way to improving performance and reducing labor requirements. Normally a combination of the aforementioned limiters can effectively manage intake levels but it will take other physical management such as feeder placement, water and free-choice mineral availability to make the program truly successful. Also, each group of cattle is different and must be managed as such. What is effective in limiting intake in one group may need to be modified to control the next. Doing your homework, strategizing and a little experience will go a long way to implementing an effective supplementation program.
Dr. Steve Blezinger is a nutritional and management consultant with an office in Sulphur Springs, TX. He can be reached at P. O. Box 653, Sulphur Springs, TX 75483, by phone at (903) 885-7992 or by e-mail at email@example.com.