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Reprinted from Kent's Beef Producer News Most cattle feeders can tell you how a particular group of finishing cattle gained or "closed out." However, they might have a more difficult time if you ask them what type of gain curve the cattle developed in achieving that close out. What do you mean by "gain curve?" 
During the feeding period, daily gain for finishing steers and heifers is not constant, but will be on a curve (not unlike the principle of the lactation curve for dairy cattle). The type of gain curve a pen of cattle is allowed to develop depends on management, nutrition, environment, age, sex and genetics. Figure 1 gives an example of a gain curve for a set of medium-framed steers that "closed out" with a 3.1 lb. per head per day gain and a $42.20 per cwt cost of gain (feed and non-feed). What are the characteristics of a good gain curve? 1. A smooth, consistent daily gain from start to finish. 2. A high sustained curve with cattle "peaking" in gain at the right time or body weight. 3. At approximately 85 percent of "ideal" slaughter weight, gain (and often intake) will begin declining quickly. A feeder who records and pays close attention to intake can usually see this happening. 4. The chart to the right shows "gain curve" guidelines for finishing daily gains for medium-frame cattle. 
Why feed cattle with a gain curve in mind? 
1. When feeding for a gain curve, the feeder is indirectly feeding for a cost of gain curve. Note in Figure 2 how cost of gain for the cattle shown in Figure 1 is almost a mirror image of their gain curve. Developing a high, sustained gain curve promotes a lower cost of gain for a longer period of time. Feed per gain and cost of gain curves run parallel. 2. Note also in Figure 2 how breakeven decreases as cattle are fed. The difference between the cost of gain and breakeven lines is known as the feeding margin. Feeding for a high, sustained gain curve means a feeder is really working to maximize the feeding margin so that final breakeven is brought as low as possible. 3. Note how quickly cost of gain increases (Figure 2) as cattle finish and the gain curve (Figure 1) declines. When the cost of gain and breakeven lines cross, the feeder has lost feeding margin and breakeven starts increasing. By the time the two lines intersect, the cattle are well finished. Can cattle peak in gain too soon? 1. Yes, the steers in Figure 3 were allowed to peak in gain early at 700 to 750 lbs. Note how quickly their gain curve declined and the cost of gain curve (Figure 4) increased. These cattle closed out with a 2.5 lb. per day gain and a $50 per cwt cost of gain. 2. During the first 100 to 150 lbs. of gain, cattle are especially prone to acidosis resulting from poor feeding management, excessive/erratic intake and too much corn or energy. Peaking in gain too soon results in poor performance later in the feeding period because of acidosis or from cattle finishing and maturing too quickly. 
How do you feed/manage for optimum, consistent gain and cost of gain curves? 1. The diet should contain its maximum energy content (.62 to .63 Mcals NEg per lb. of dry matter) by the time steers weigh 900 and heifers weigh 850 lbs. 2. Work to keep intake consistent. Avoid overfeeding cattle and allowing erratic intake patterns to develop. Erratic intake usually means acidosis and poor gain and cost of gain curves. In many cases the gain curve will "drop off" prematurely before cattle are finished. 3. Keep cattle slightly hungry. Increase intake to where some feed is left in the bunk. At this point back off intake by 1 lb. per head and keep it there for at least seven to 10 days before considering any increases. Make sure total dry matter increases are no greater than 1 lb. per head. 4. Make diet changes gradual and systematic. 
5. Keep accurate daily intake records and constantly push the pencil to monitor dry matter intake. Daily dry matter intake of a "hot" finishing diet should be at 2.25 percent to 2.5 percent of body weight at "peak" and will drop quickly to 1.5 to 1.8 percent when the cattle finish. Avoid dry matter intakes exceeding 2.75 percent as this often occurs just before a "train wreck" and a severe intake drop due to acidosis. 6. The final finishing diet should contain at least seven to eight percent acid detergent fiber (ADF) on a dry matter basis to ensure sufficient effective or "chewable" fiber is present to promote rumen health and reduce the incidence of acidosis. 7. Make sure the cattle have an active implant in the ear up to the time of slaughter. An effective implant program can "push" the cost of gain lower independently of intake. This means knowing how long a particular implant is effective and when the bulk of the cattle will be marketed. 8. Make sure the diet contains the proper mineral fortification. Kent research has found finishing gain and cost of gain curves can be significantly enhanced with the right levels and ratios of calcium, potassium, and magnesium.  These are termed Precise Mineral Additions (PMA) and in some cases have improved return per head by $20.
9. Provide the right source and level of protein in the diet. Kent Feeds has devoted years of research to determining the ideal levels and combinations of rumen available and undegradable protein needed in the diet to provide the most profitable gain and cost of gain curves. |
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