Conventional  and genomic breeding value for clinical mastitis

ZAVADILOVÁ, Ludmila, ŠTÍPKOVÁ, Miloslava and BAUER, Jiří. Conventional  and genomic breeding value for clinical mastitis. Náš chov, 2016, vol. 76(1), p. 55-59. ISSN 0027-8068.
CathegoryPublication in specialized journals
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The conventional and genomic breeding values were estimated, based on a dataset of cows 15,905 (36,250 lactations) from 10 farms calving from 1996 to 2014. The number of genotyped bulls was 2647 and 799 of them had offspring among the surveyed cows. Pedigree consisted of 64,306 individuals. The analyzed trait was defined as the incidence of clinical mastitis per standard lactation. Parity was limited to 1 to 7. The highest proportion of mastitis disease was observed in early lactation and decreased with month of lactation, while there was a rise of diseases with parity. Genetic trend for cows showed a deteriorating tendency for clinical mastitis. From 1992 to 2010 there was a rise in the relative values of breeding values from 88% to 112% (worsening). Relative breeding values of the bulls in those years, on average lie above 100%. Possibility of selection of cows by breeding values for the number of cases of clinical mastitis per lactation was shown in heifers calving year 2012. The correlation between classical genomic breeding values and the values were high: 93% for the whole sample, 81 % to 48 young genomic bulls without daughters born in years 2011 and 2012.