Application of BLUP AM in Russian Ayrshire Cattle Breeding Value Evaluation

Contemporary comparison method is used officially in Russian Federation to predict bulls breeding values (BV). In genomic era Russian farmers are interested in getting genomic predictions for animals their are keeping, especially heifers and young bulls. To make a gap to genomic prediction, from old system, it is necessary to use Internationally approved system of BV evaluation. Among plenty of BLUP models, Repeatability Animal Model was chosen as effective tool for BV evaluation in Russian Ayrshire cattle. Leningrad district is placed on north-western part of Russia, having borders with Finland and Kareliya region, who actively use and breed Ayrshire cattle. Data from 8 large herds (>700 cows) were used to develop the Repeatability Animal Model BLUP. Pedigree records of 80000 animals born in 1990-2015 were available together with 32000 milk records, including 305d milk yield, fat yield and protein yield in kg. Milk yield, fat and protein contents were measured once a month during lactation (~10 measurements). Average 305d milk yield was 6357 kg (SD=1431), average fat yield was 254 kg (SD=57), and average protein yield was 227 kg (SD=54). A repeatability animal model with five lactations was used for variance component estimation and for breeding value estimation. Model included herd-year-season and age at calving x days open fixed effects. Outliers with records +/-3 SD from the mean were excluded from the analysis. DMU software package was used to estimate variance components. Heritability and repeatability estimates were for milk h2=0.23 and r=0.4, for fat h2=0.24 and r=0.37, and for protein h2=0.25 and r=0.38, respectively. DMU4 was used to estimate breeding values. Average genetic trend for milk yield for cows born from 2002 to 2014 was +20 kg per year.