|HOUDEK, ERIC - University Of Minnesota|
|HEINS, BRADLEY - University Of Minnesota|
|HAZEL, AMY - University Of Minnesota|
|HANSEN, LES - University Of Minnesota|
Submitted to: Journal of Dairy Science
Publication Type: Abstract Only
Publication Acceptance Date: 3/10/2019
Publication Date: 6/23/2019
Citation: Houdek, E.S., Heins, B.J., Hazel, A.R., Hansen, L.B., Cole, J.B. 2019. Alternative input parameters for Wood’s curve within Best Prediction used by USDA-AGIL for genetic evaluation of production traits in the United States. Journal of Dairy Science. 102(Suppl. 1):399(abstr. 468).
Technical Abstract: Best Prediction (BP) was developed by USDA-AGIL to predict 305-day lactational production for genetic evaluation in the US. Mean and SD of test days for all production traits are used by BP to predict either primiparous or multiparous 305-day production based on a Wood’s lactation curve. Fixed Holstein (HO) breed parameters for Wood’s curve currently used by BP since 2009 were compared to alternative parameters that were newly estimated. The new parameters were implemented to determine if increased production of cows and reduced use of rBST over the past decade has impacted the effectiveness of BP to predict 305-day production of milk, fat, and protein. Test-day observations of HO cows from 7 high-production dairies in Minnesota that have participated in research with the University of Minnesota were used to estimate the alternative BP parameters. The primiparous cows calved from 2011 to 2016, and the multiparous cows calved from 2012 to 2016. All lactations of cows were required to have at least 250 days in milk and were also required to have at least 6 test days by 265 days in milk. Shapes of Wood’s lactation curves for these three production traits from BP were noticeably different for the currently used versus alternative fixed breed parameters. However, when the 305-day production records of cows were deviated within months of calving according to procedures used for genetic evaluation in the US, the differences between the two alternative predictions of 305-day production were of no practical consequence.