WHAT DO YOU NEED TO KNOW ABOUT CHANGES IN DHIA?
Allen J. Young
USU Extension Dairy Specialist
Starting last January, DHIA changed the way it did business. The intent is to get out of the "policing" business and to let the end-user of the records determine how accurate the records are. To do this the portion of DHIA previously called rules has been changed to procedures, dairy producers were asked to sign a code of ethics, and a special herd summary called a Herd Profile (don't confuse this with the Herd Profile which is available from Provo-DHI) has been developed. This profile is available to the dairy producer and end-users of that producer's record. The intent of the Profile is to give
information that can help a person or organization determine how "good" the records are.
In addition, the designations of "official" and "unofficial" are no longer valid. Again, the end-user determines the value to place on records coming from individual dairy producers. For example, now owner-sampler herds can have their records used for genetic evaluation and used in the sire summaries. However, to be considered, these herds must meet the following minimum requirements:
1. 40% of the animals in the herd must have a complete ID (a unique number, sire ID, and birth date).
2. Amount of milk shipped (average of bulk tank pickup) must be between 81 and 117% of the sum of individual cow's milk from that DHIA test.
3. Weighing equipment must meet DHIA quality control standards.
4. Herds must have less than a certain portion (approximately two - this comes from the Herd Profile) of probable outliers (cows that are statistically extremely high or low).
If you meet the minimum requirements, the records from your cows may be used in genetic evaluations.
There is one final adjustment given to the records. This is related to the number and type of DHIA tests which an animal has. The Animal Improvement Programs Laboratory (AIPL) from USDA, the Holstein Association, and most A.I. organizations have developed something called a Data Collection Rating (DCR). This is a weighting factor which tells how much information that animal/herd will contribute to the evaluations. The greater the number of supervised DHIA tests a dairy has within a year, the greater the value ascribed to that record. For example, AIPL puts 100% value on a cow which has 10 supervised tests in a lactation, but only 76% if it is an owner-sampler herd with the same number
of tests. If an animal or herd is only tested five times in a year then AIPL assigned a weighting of 75% for a supervised test and the Holstein Association assigns it a 93% value. The Holstein Association suggests a minimum score of 91% for milk to be classified under its Premier option. My understanding is that A.I. organizations are using a similar DCR to manage their young sire programs. Which DHIA testing schedule you decide on will depend on what your records are used for. The major concern for many dairies should be that in order for the record of a cow to be used in any program (AIPL, Holstein, etc.) she MUST have a least one test within the first 75 days after calving. If she doesn't, her records, and possibly those of the herd, will not be used because there is no way to calculate a lactation curve for the animal.
If you have any questions relating to your DHIA testing schedule and how it will affect the way you do business, contact your DHIA technician, Holstein representative, or A.I. organization (if you are involved with a young sire program). I also have information on interpreting the new Herd Profile if you should need it.