He received his bachelor's degree in dairy science from Texas A&M University in 1983, his master's in animal science with an emphasis in dairy cattle nutrition from Texas A&M University in 1990, and his doctorate in animal science with an emphasis in dairy labor management in 2002. Dr. Holub served as a County Extension Agent from June 1984 until January 1996. From June 2001 until June 2006, he served as a dairy cattle nutritionist in North Central Texas and Eastern New Mexico. Currently, Dr. Holub is conducting dairy calf nutritional research and effects of heat stress on dairy calves.