The environmental factors of climate, nutrition, and management are considered major stressors on animal health and production. Those external factors or stimuli are transduced by different receptors and may result in epigenetic changes in the absence of any changes in gene sequence in cattle. Although it is well known that phe- notypes are influenced by both the genotype and the environment, major gaps still exist in the current under- standing of mechanisms by which environmental factors modulate phenotype, development and disease within an organism. For example, the level of feeding of sires was shown to affect milk production in daughters [3], and dietary treatments were shown to hasten the onset of puberty and altered gene expression in the arcuate nu- cleus of beef heifers [4]. Also, it is known that season can have major impacts on the reproduction, lactation and growth of cattle [5]. However, environmental effects on the genome and epigenome must be investigated fur- ther before they may be used to predict performance and improve selection for superior animals.