Submitted to: Journal of Dairy Science
Publication Type: Abstract Only
Publication Acceptance Date: 2/17/2006
Publication Date: 7/9/2006
Citation: Wiggans, G.R., Thornton, L.L., Neitzel, R.R. 2006. Genetic evaluation of milking speed for Brown Swiss dairy cattle [abstract]. Journal of Dairy Science. 89(Suppl. 1):248(abstr. 259). Interpretive Summary:
Technical Abstract: Genetic parameters and breeding values (EBV) were estimated for milking speed in Brown Swiss cattle. Owner recorded milking speed scores on a 1 to 8 scale (low to high) were collected by the Brown Swiss Association as part of its linear type appraisal program starting in 2004. Data were 6,483 records on 6,017 cows in 352 herds. A total of 13,192 ancestors and seven unknown parent groups, each including four years of birth, also were included. The model included fixed effects for herd appraisal date, parity-stage of lactation, and random effects for permanent environment, animal and error. Four 90-day stages of lactation were defined. An Average Information REML variance estimation procedure produced heritability of 0.22 and repeatability of 0.41. The residual variance was 1.13. There was little trend in EBV of cows born 1999 through 2002. The 109 bulls with 10 or more daughters had a range in EBV of 2.7. Speed increased with stage of lactation for first parity cows by 0.37. There was not a clear trend in second parity, and in third and later parities, there was a drop of 0.20 from the first to the third 90-day period, then an increase of 0.10 in the last period. For the 109 bulls with 10 or more daughters, significant correlations between evaluations for milking speed and other traits were 0.22 for milk, 0.53 for productive life and –0.37 for somatic cell score. The association of faster milking speed with lower somatic cell score was not expected. The milking speed information can provide useful EBV given the moderate heritability. Similar data is being collected for Holsteins, so this evaluation system could be extended to that breed.