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Virginia Cooperative Extension - Knowledge for the CommonWealth

The DHI system contributes to better dystocia proofs

Dairy Pipeline: August 2002

Bennet Cassell
Extension Dairy Scientist,
Genetics and Management
(540) 231-4762
email: bcassell@vt.edu

A recent note in Pipeline was about USDA research to develop a new genetic evaluation for dystocia in cows called "Daughter calving ease." Producers already have access to dystocia proofs for service sires called "Percent difficult births in heifers" or %DBH. Daughter calving ease proofs will use the same calving difficulty scores, but only if the sire of the cow giving birth is identified. A record of calving difficulty on a calf whose sire is known, but whose dam has no sire ID, cannot contribute to daughter calving ease proofs. Submitting calving ease information is easy. When test day approaches, list cows/heifers that have calved since the last visit by the DHI tester and record a calving difficulty score for each cow or heifer as follows: 1 for no difficulty, 2 for minor problem, 3 for needed assistance, 4 for considerable force, or 5 for very difficult. Report scores for all births, not just the easy ones or the difficult ones, as selective reporting distorts the information. The DHI technician can easily enter calving difficulty scores with each calving record as long as the producer has the information available. Plan ahead, because no score will be entered if the producer is in the hay field on test day and the milker has no idea what difficulty score should be assigned to Helga or Frosty. By using the DHI system, all the available pedigree information about each calf sire, dam, maternal grandsire, and further back is automatically associated with the calving difficulty record. DRMS Raleigh forwards the assembled data to USDA for genetic evaluations. Accurate data files depend on professionals using good computer software, which DHI provides. The key to accurate original data, however, is the dairy farmer who must consistently evaluate and record birth difficulty. There is no information system that can make informative and useful proofs out of misleading, incomplete, or biased data. The real key to accurate genetic evaluations for service sire dystocia or the soon-to-be daughter dystocia proofs is the dairy producer who observed the birth directly.



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