Sprague Dawley Rats (CD® IGS)

Known for their calm demeanor, adaptability, and genetic reliability, the Sprague Dawley (SD) rat has become indispensable for advancing our understanding of human health and disease. From pharmacology to cancer research, SD rats play a crucial role in helping scientists answer complex questions. Our Sprague Dawley rat, the caesarean-derived (CD) IGS rat, originated in 1925 by Robert W. Dawley from a hybrid hooded male and a female Wistar rat. This rat was given to Charles River in 1950 by Sprague Dawley, Inc. In 1991, eight colonies were selected to form the IGS foundation colony. The Sprague Dawley rat was rederived into an isolator foundation colony in 1997.IGS refers to animals bred using the Charles River International Genetic Standardization Program, including the Crl:CD(SD) rat. The IGS program is a management system used to minimize inbreeding and manage random genetic drift that would otherwise lead to colony divergence among colonies bred in different locations worldwide. The IGS program is validated by direct genetic analysis of animals from the foundation colony and the barrier rooms.Note: We also offer the CD® (SD) IGS SOPF Rat, which is bred in France.