The beef herd can be straightbred or crossbred, or combinations thereof.[1-3] Heterosis (hybrid vigor) derived from breed crossing increases reproductive performance in cows and bulls. Production involving crossbred cows bred to a bull of a third breed can increase total production by up to 20%. Genetic goals can be attained through planned matings, culling, and selection. Selection progress depends on trait heritability, accuracy of trait measurement, and intensity of selection.[4] Heritabilities of reproductive performance are low, but must not be ignored. Heritabilities of reproduction components, e.g., age at puberty, are higher, and selection response is more rapid. A selection/culling strategy for improving reproduction should include: 1) selecting cows and replacement females that calve early in the calving season, that calve with minimal obstetrical difficulty, that have superior maternal ability and sound udders with moderate milk production, and are physically sound; and 2) culling nonpregnant and late-calving females. Sires (natural service) must exceed minimum criteria for testicle size (scrotal circumference), semen quality, mating capacity, and physical soundness, in addition to desired growth and carcass traits. Sires used for artificial insemination (AI) are selected on individual and offspring performance records appropriate for achieving management goals.

Pregnancy Nutrition

Pregnancy Nutrition

Are You Expecting? Find Out Everything You Need to Know About Pregnancy and Nutrition Without Having to Buy a Dictionary. This book is among the first books to be written with the expertise of a medical expert and from the viewpoint of the average, everyday, ordinary,

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