03080naa a2200325 a 450000100080000000500110000800800410001902400520006010000180011224501100013026000090024052021450024965000220239465000230241665000170243965000170245665000110247365000180248465000140250265000100251665000220252665000140254865300190256270000190258170000250260070000220262570000190264770000200266677300680268621729362025-02-19       2025    bl uuuu     u00u1 u    #d7 ahttps://doi.org/10.1007/s11250-025-04287-w2DOI1 aLIGORI, V. A.  aEconomic values and selection indexes for dairy traits in Guzerat breed in Brazil,h[electronic resource]  c2025  aEconomic efciency is afected by several traits, and as the unit of selection is the individual, in artifcial selection, to promote the maximization of economic genetic gain, the traits to be improved must be weighted by their respective economic values. In Brazil, breeding goals are defned empirically, and not based on an economic evaluation, therefore, the aim of this study was to estimate economic values for traits of economic importance in dairy farming systems based on the use of purebred and crossbred Guzerat animals. The economic values for 305-days milk yield (MY), fat yield (FY), protein yield (PY), and somatic cell count (SCC) were calculated for diferent production systems based on the feed management: System 1, based on pasture grazing with Brachiaria brizantha or Panicum maximum cv. Mombaça during rainy season, and corn-silage supplementation during the dry season; System 2, based on pasture grazing with Brachiaria brizantha or Panicum maximum cv. Mombaça during rainy season, and the mixture of sugarcane including urea supplementation during the dry season. Bioeconomic models were applied to estimate economic values, and a sensitivity analysis was performed. Four selection indexes were defned, each one with diferent goals: milk (I1), milk+protein yield (I2), I2+fat yield (I3) and I3+somatic cell count (I4). The economic values for MY and PY were positive for both production systems. However, for FY, the values were positive for System 2 but negative for System 1. The economic value for SCC was negative (-7.33 per SCS per lactation). The selection responses for I1 were higher than those for I2, I3 and I4, for both production systems. I4 presented the highest expected genetic gain for each trait, except for fat yield, whose expected genetic gain was greater with the use of I2, in both production systems. The results indicates that the inclusion of milk quality traits in the selection index provides better economic return, and due to the small diferences in expected genetic superiority, I1 is still the most suitable for crossbred Guzerat herds whose main activity is milk production in Brazil.  aAnimal production  aBioeconomic models  aDairy cattle  aMilk quality  aBovino  aGado Leiteiro  aGado Zebu  aLeite  aProdução Animal  aQualidade  aBreeding goals1 aCARDOSO, V. L.1 aPEIXOTO, M. G. C. D.1 aBRUNELI, F. A. T.1 aCARRARA, E. R.1 aZADRA, L. E. F.  tTropical Animal Health and Productiongv. 57, article 46, 2025.