Fat-corrected milk and/or solids-corrected milk are really better benchmarks to help you decide how much milk you're getting. Here are two formulas you can use to accurately gauge milk production.
By Rick Lundquist, Ph.D.
How much milk are you getting? That’s how most of us compare production. Fat and protein are usually secondary. But to accurately gauge milk production, we should account for butterfat, protein and even lactose. Fat-corrected milk and/or solids-corrected milk are really better benchmarks.
With more Jersey blood and other colored breeds in many herds, higher components skew comparisons. On the other hand, milk yield with low butterfat or protein should be discounted for comparison purposes.
Two formulas can be used, depending on whether you are in a fluid or a cheese market:
1. 3.5% Fat Corrected Milk, lb. = (0.4324 x milk, lb.) + (16.218 x (milk, lb. x fat %)).
2. Solids Corrected Milk, lb. = milk, lb. x ((12.24 x fat %) + (7.1 x protein %) + (6.35 x lactose %) - .0345)
Fat, protein and lactose percent should be entered as decimals in these equations. Entering the equations into a spreadsheet will make the math easy.
If, for example, you have a Jersey x Holstein herd averaging 65 lb. of 4.2% fat milk: 3.5% fat corrected milk = ((0.4324 x 65) + (16.218 x (65 x.042)) = 72.38 lb.
If you have a Jersey herd giving 60 lb. of 5.2% fat, 3.8% protein, 5.0% lactose milk: Solids corrected milk = 60 x ((12.24 x .052) + (7.1 x .038) + (6.35 x .05) - .0345) = 71.35 lb.
It takes energy to produce fat, protein and lactose. Yet, we tend to look at just milk yield as long as components aren’t real low or real high.
When fat test in Holstein herds is high, I often hear the comment that we could get more milk if we fed for lower butterfat. And in some cases this may be true. However, I caution that feeding a ration that is potentially unhealthy is not the solution. The fat corrected milk equation can help you determine where your milk production could be if the available energy was partitioned for more volume and less fat. Using these formulas gives us a more accurate picture of production: apples to apples.
Contact Rick Lundquist at email@example.com.