Farmers' Bulletin, العدد 1167

ancestors animal breeding appearance become begins birth Blood body breeder breeding animals bull carried cattle champion chance character characteristics chromosomes color combinations common considerable depends determining domestic animals effect elements explained face fact farm fecundity female fertilized flock four germ cells gestation grading head heat herd hereditary material heredity Hereford hogs horse human identity importance impression improvement inbred inbreeding increase indicate individual inheritance July knowledge known lamb livestock look male Mare mating maturing Mendel's law merit methods months mother nature Note operation pairs parents pedigree period Photograph points polled possible practical prepotency principles probably produce progress Pure Blood purebred remarkable rule selection shown sire skillful sows species sperm cell stallion strains strong successful taken theory uniform unite usually uterus valuable vigor young