The Study of Genetic Improvement of Tolerance for Anemia Development and Investigation of Physiological Indicator.

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(1) We estimated genetic and phenotypic parameters between PCV and calf productivity in the 437 Japanese shorthorn calves. The PCV at pre-grazing (PrePCV), minimum PCV (MinPCV) and daily gain (DG) during grazing were measured from 220, 415 and 400 calves, respectively. Heritabilities of PrePCV MinPCV and DG were estimated 0.61, 0.16 and 0.67, respectively. Simultaneously improvement of anemia tolerance and productivity is expected to be quite feasible. However, this improvement will increase normal PCV, so that some selection criteria to improve anemia tolerance and productivity without the increase of normal PCV are necessary.(2) We examined mutual relationships among the anemia development, liver dysfunction and lipid metabolism and discussed which plasma component was adequate for physiological indicator for genetic improvement of anemia tolerance. By multiple traits analysis, lipid components associated with HDL, phospholipids (PL) and total cholesterol (TC), would closely related anemia development.(3) We estimated genetic and phenotypic parameters between PCV, calf productivity and physiological indicator in the 437 Japanese shorthorn calves, and discussed whether the application of physiological indicator, PL and TC, for genetic improvement was useful or not. Heritabilities of PL and TC were 0.31 and 0.09, respectively. It was suggested that more efficient improvement would realize by introduce physiological indicators into selection indices. PL and TC would be suggested sufficiently useful indicators for genetic improvement of anemia tolerance.