Limit feeding backgrounding cattle by Dr. Aaron Grant and Dr. Scott Schake Nutrition Service Associates
December, 2009
Due to the cold and dry conditions in many parts of Alberta and Saskatchewan this summer, cattle producers are faced with a forage deficit heading into winter. This has left many producers searching for alternative methods with which to feed their cattle. Although making use of poor quality forages (Canola silage, straw etc.) may be feasible in certain situations, their nutritional value leaves a lot to be desired. Fortunately however, there are options when it comes to feeding cattle with minimum forage usage. Feeding rations containing high concentrate to forage ratios on a limited basis is an extremely effective way to maintain &/or grow cattle. This article will focus on the benefits of limit feeding backgrounding/growing cattle.
In essence, limit (or programmed) feeding is the control of an animal's feed consumption by the cattle feeder rather than by the animal itself. It is a well established fact that cattle fed high grain diets are more efficient than those fed high-forage rations. Therefore, limit feeding a high grain diet results in greater ration digestibility & energy utilization due to slower feed passage through the digestive tract, allowing more complete nutrient absorption. Additionally, the productive energy in limit-fed cattle is much more predictable vs. ad-libitum fed animals because the net energy value of grains is more consistent than that of roughages, especially those of poor or inconsistent quality. Due to the advantages in ration consistency and energy retention by the animal itself, cattle performance can be more accurately predicted with limit feeding.
Due to the improvement in energy utilization vs. ad-libitum diets, limit feeding backgrounding/growing cattle consistently results in improved feed conversion. Numerous research trials & reviews have documented improvements in feed conversion between 1% & 25%, depending on the level of intake restriction. One such literature review conducted by Oklahoma State University concluded that in cattle fed moderately restricted diets (less than 15% of ad libitum) feed efficiency improved by approximately 0.6% for each 1% of intake restriction. Canadian feedlot trials have observed similar improvements in feed efficiency. University of Saskatchewan researchers found that limit feeding improved feed conversions by 15% to 22% vs. ad-libitum feeding with similar total energy intakes. Although difficult to determine, the authors suggested the improvement in feed efficiencies may be attributed to a number of factors including slower rate of passage, increased rumen retention time, increased ruminal dry matter degradation, and lower maintenance requirements.
Because feed intake and diet net energy densities can be controlled by limit feeding, one can be extremely precise in targeting average daily gains. Formulating diets to contain an appropriate amount of energy to target specific daily gains is critical to any limit feeding program and can be a dilemma for any cattlemen who attempt it. One approach is to limit dry matter intake to a certain percentage of body weight based on the energy value of the ration. A second, and more accurate approach, is to use the NRC net energy formulas & tables. These tables can be used to calculate the energy needed for maintenance & gain of any particular class of cattle. Based on these energy values, the pounds of dry matter required can be calculated to attain the desired level of gain. Although this can be done by hand, having the assistance of a good nutritionist with access to computer formulation programs is definitely an asset. Once these calculations are made, the main determinant of a successful limit feeding program becomes good management.
Good management practices are vital to any limit feeding program. Limit feeding requires more intensive management than ad-libitum feeding and therefore, one must extremely accurate in building the ration, feeding the correct amount, & feeding at a consistent time day in and day out. As the cattle's hunger will not be completely satisfied when limit feeding, they will be more aggressive. Therefore, if any of the aforementioned management practices are not strictly adhered to, any problems that may arise will be amplified vs. ad-libitum feeding. If feed intake is restricted too much, due to inaccurate estimates of feed intake, poor ration formulation, or inconsistent feed ingredients, daily gains may suffer, resulting in cattle not meeting their projected weights for a given point in time. Alternatively if the cattle's daily gain is greater than predicted, cattle with excessive weights &/or body condition could result. Pen & bunk space are also considerations when deciding to limit feed. If the pens are overstocked or bunk space is insufficient, erratic feed intakes, increased variability in daily gain, and a greater propensity for metabolic disorders may result. Another trend that may be noted with limit-fed cattle, especially if not done correctly, is an increase in liver abscesses upon the cattle being finished. This may be attributed to high grain diets being fed for excessive amounts of time and/or increased fluctuation in feed intake or severely restricted cattle. Although there is a potential for negative effects when limit feeding cattle, the advantages in performance are evident, and can relate to economic benefits for cattle producers.
If properly managed, programmed feeding can prove economically & environmentally advantageous for cattle producers. On an energy basis, grain is almost always a cheaper source of feed than harvested roughages. This is due to the fact that grain comprises 2 to 3 times the amount of energy than most roughages. Thus, if one can reduce the amount of feed fed to cattle, while at the same time feeding a cheaper ration, the net result is a lowered cost of gain. This profit margin between limit & and ad-libitum fed cattle may be magnified when roughage &/or freight costs are high (Such as this year). Limit-feeding cattle have also proven to have environmental advantages such as decreased manure production. Due to reduced feed intake & greater feed efficiency, limit fed cattle produce less manure. This may aid in reducing nitrogen and phosphorus accretion on land, as well as reduce the costs of pen cleaning and maintenance.
Limit feeding cattle can show productive, economic, & environmental benefits to cattle producers. From improving feed conversion and reducing cost of gain, to lowering the environmental impact on farmland, limit feeding is a sound cattle production tool. However, when attempting to limit feed cattle, one must recognize the potential drawbacks and adhere to the increased management practices that go along with it.
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