Robert W. Everett - Professor
PhD from Michigan State U.
Graduate fields: Animal Science, Animal Breeding
Area(s) of interest: statistical and quantitative genetics, dairy cattle breeding
Email: rwe2@cornell.edu
Current Research
Evaluating individual dairy cows and the management of a dairy herd has become increasingly complex as farmers adopt new technologies and improve their herd management programs. Improved production efficiency increases the profitability of individual farms and reduces the cost of food for the consumer.
Using 305-day mature equivalent lactation records. However, this requires a national set of factors for adjustment of cows' records for age, stage of lactation, gestation, etc. Furthermore, it is difficult to evaluate treatments during parts of a lactation using 305-day records.
The Test-Day Model(TDM) evaluates production of cows on test day rather than on 305-day production records. This allows each herd to have its own adjustments for age, days in milk (DIM), days carried calf (DCC), and month of freshening (MF). Test-day production residuals (adjusted for age, DIM, DCC, MF, and management milk) are excellent indicators of a cow's performance. Test-day residuals can be combined to form lactations of any length, which are free from many sources of variation. This suggests TDM residuals have higher heritability, which produces higher accuracy in genetic evaluations. With TDM residual records, alternatives to the traditional dairy progeny testing program become more practical and economical.
Our work over the past few years has been with the Test-Day Model. Future work will emphasize the implementation of the TDM for herd and genetic evaluation programs.