Editor's note: The following ran in the May 2010 edition of Dairy Herd Management.

When milk prices declined, parts of the country saw dramatic decreases in the number of dairy herds that participated in Dairy Herd Improvement Association (DHIA) testing. When times are tight, it is more important than ever to have reliable information to make sound decisions. Test day provides you with more health and production information than any other single daily activity.

If you are one of those that dropped this service, here’s what you are missing.

  • Production. Milk production is the most obvious data. Productive cows are healthy cows. Look at milk production by pen, peak milk, milk deviations from test to test, performance of cows by lactation group, low cows, high cows and persistency, to name a few.
  • Components. Many times, component information is the first area of a test to be cut. However, there is a lot of insight about health gained from analyzing components. For example, fat and protein ratios tell us about acidosis, energy and the transition period of the herd. Many farms think they can solely rely on bulk tank or string sample components. While these are great tools for monitoring the herd, relying on averages can be quite misleading. 
  • Somatic cells. Somatic cell information is a great indicator of udder health. This information tells us about the effectiveness of the dry cow program, pen hygiene management, parlor routines, infection status of the herd, effectiveness of lactation therapy, chronic mastitis cows and subclinical mastitis status.
  • Milk urea nitrogen. MUN levels in individual cows are a useful gauge for evaluating carbohydrate and protein levels in the diet. Examine the average level of MUN by pen, as well as to look at the minimum and maximum levels in a pen and to follow the median by pen from test to test. I caution my clients not to focus on individual cow MUN values, but look for trends within a group. 
  • Reproduction. While many on-farm software systems do a great job in tracking and evaluating reproduction, DHIA reports can provide an easy way to benchmark and find hidden profits. Evaluate conception rates, pregnancy rates, average days to first service, average days open and age at first calving. To help benchmark, your farm can be compared to other dairies in your region and across the nation.
  • Other health add-ons. There has been a lot of activity in the area of developing tests that utilize test-day milk. This is an efficient means of testing an entire herd or portions of the herd with no added farm labor. Currently, bovine viral diarrhea, Johne’s disease, leucosis and mastitis pathogen tests are available on test-day milk.
  • Inventory. Not only is it handy to have a third-party inventory, but this information is obviously important for day-to-day management. As it relates to health, stocking densities are important information when troubleshooting health problems. 
  • Quality control for on-farm meters. For farms that utilize on-farm metering systems for daily milk production, DHIA testing will allow for quality control of those meters. Just ask your tester to provide a comparison of the weights for a few turns. This will quickly identify if any maintenance is needed on any of those meters. Because daily milk-weight variation is an important and early indicator of health, it pays to have accurate information. 

Test-day information provides a wealth of health information for you and your consulting team. Both your veterinarian and nutritionist utilize this information to look for trends, evaluate the effectiveness of programs and gain an understanding of what is really going on with cows. Maybe today is the right time to give your DHIA tester a call.

Angela M. Daniels is a veterinarian with Circle H Headquarters LLC, a dairy and swine veterinary practice, food safety laboratory and DHIA milk-testing and contract research organization in Dalhart, Texas.