02505naa a2200241 a 450000100080000000500110000800800410001902400460006010000190010624501720012526000090029730000090030652017070031565000160202265300230203865300230206165300200208465300250210470000150212970000170214470000220216177300800218320434532022-08-10       2015    bl uuuu     u00u1 u    #d7 ahttps://doi.org/10.5713/ajas.15.04982DOI1 aPADILHA, A. H.  aRandom regression models are suitable to substitute the traditional 305-day lactation model in genetic evaluations of holstein cattle in Brazil.h[electronic resource]  c2015  a9 p.  aThe aim of this study was to compare two random regression models (RRM) fitted by fourth (RRM4) and fifth-order Legendre polynomials (RRM5) with a lactation model (LM) for evaluating Holstein cattle in Brazil. Two datasets with the same animals were prepared for this study. To apply test-day RRM and LMs, 262,426 test day records and 30,228 lactation records covering 305 days were prepared, respectively. The lowest values of Akaike?s information criterion, Bayesian information criterion, and estimates of the maximum of the likelihood function (?2LogL) were for RRM4. Heritability for 305-day milk yield (305MY) was 0.23 (RRM4), 0.24 (RRM5), and 0.21 (LM). Heritability, additive genetic and permanent environmental variances of test days on days in milk was from 0.16 to 0.27, from 3.76 to 6.88 and from 11.12 to 20.21, respectively. Additive genetic correlations between test days ranged from 0.20 to 0.99. Permanent environmental correlations between test days were between 0.07 and 0.99. Standard deviations of average estimated breeding values (EBVs) for 305MY from RRM4 and RRM5 were from 11% to 30% higher for bulls and around 28% higher for cows than that in LM. Rank correlations between RRM EBVs and LM EBVs were between 0.86 to 0.96 for bulls and 0.80 to 0.87 for cows. Average percentage of gain in reliability of EBVs for 305-day yield increased from 4% to 17% for bulls and from 23% to 24% for cows when reliability of EBVs from RRM models was compared to those from LM model. Random regression model fitted by fourth order Legendre polynomials is recommended for genetic evaluations of Brazilian Holstein cattle because of the higher reliability in the estimation of breeding values.  areliability  a305-Day Milk Yield  aBrazilian Holstein  aBreeding Values  aLegendre Polynomials1 aCOBUCI, J.1 aCOSTA, C. N.1 aBRACCINI NETO, J.  tAsian-Australasian Jounal of Animal Sciencegv. 29, n. 6, p. 759-767, 2015.