Impact of somatotropin and other biochemical products on sire summaries and cow indexes.

This paper outlines the potential impact of bovine somatotropin on dairy cattle improvement programs and pinpoints research needs. Recording of manufacturer, dosage, and date of start and finish of somatotropin administration is recommended in order to allow analysis of data for cow and sire ranking. Alternatives, such as restriction of somatotropin administration to certain lactations or parts of the cow's lactation are discussed. Cooperator herds or nucleus breeding schemes as alternatives to the random sampling of AI bulls may become more practical if somatotropin is widely used in the future.