How Efficient is Your Ration?

Dr. Allen Young
USU Extension Dairy Specialist

Efficiency is the name of the game right now. It is a measure of how many pounds of milk you are getting for each pound of dry matter that you feed your cows. This was the take-home message from Dr. Mike Hutjens� talk at the IFA meetings. It has also become important to dairy farmers now that Rumensin has been legalized for lactating cows. If you understand the claim that comes with this product, you realize that you need to be calculating feed efficiency or you may not know if it is working for your cows. In addition, there are 19 different feed additives on the market that all make claims of success for your cows. The following is a reminder of how to go about doing this on your dairy given the several management constraints in feeding cows.

The first item you need is the pounds of milk per cow per day. As simple as this sounds, it is sometimes a problem to correctly derive these numbers on a dairy. You can use DHIA numbers and/or if you have meters, you can get the pounds of milk per cow from daily readouts. If you don�t have meters, use the bulk tank pickup pounds and divide by the number of cows whose milk went into the tank. Remember to divide the milk by 2 if you have every-other-day pickup. If you want to be completely accurate, add back in the estimated pounds of milk taken out for calves. It is suggested that you use fat-corrected milk (3.5 FCM) or solids-corrected milk (SCM) values. This means you need the fat or fat and lactose percents to complete the calculations. Again, you can use DHIA values or the average bulk tank milk fat and lactose % to complete the calculations. I have looked at the values using the actual milk compared with 3.5 FCM and I haven�t seen very many differences, assuming the fat percent is fairly stable. Now that you have the pounds of milk per cow (whole-herd or by strings), you need to determine dry matter intakes (DMI).

This is usually where the process breaks down. If you have a feeding management program such as EZ-Feed or Feed Track, you can pull out the pounds of DM fed per cow per day easily (again whole-farm or by string). All you have to do now is match the DM with the milk weights. If you don�t have a program like this, you are going to have to work a little harder to get the numbers you need. If you are feeding a TMR, write down the total pounds fed per day and divide by the number of cows fed. You will still need to estimate the DM % so you can make the conversion from as-fed to DM. If you want to be more precise, record the pounds of each commodity as it goes into the mixer wagon and convert to DM by commodity, then sum the pounds for the day and divide by the number of cows for the herd or sting. If you don�t do any of the above, you can still estimate the pounds of feed by counting the bales fed per day and divide by the cow number and add the pounds of concentrate fed per cow.

Now that you have two required numbers, divide the pounds of milk by the DMI to get a milk per DMI efficiency number. Dr. Hutjens suggested the following guidelines as benchmarks for efficiency:

One-group, all cows >1.4
High group, 1st lactation >1.5
High group, 2nd + lactation >1.6
Fresh cow group 1.2 to 1.4
Problem herds <1.3

If your number indicates a problem, talk with your nutritionist to devise means to resolve the problem.

I hope you make the effort to calculate this value, especially if you are using Rumensin or some other feed additive. I do this for several herds I work with and have found it to be an extremely useful exercise in evaluating ration changes and general problems on the dairy. For more information contact Allen Young at alleny@ext.usu.edu or (435) 797-3763. ©