Impact of Nutrition, Behavior and Other Stressors on Embryonic Loss and Fertility

Introduction Reproduction efficiency of the herd is optimal when replacement heifers attain puberty as yearlings and calve at 2 years of age, and cows are able to become pregnant early during the annual breeding season (Bagley, 1993). Nutrition is the environmental factor that most influences reproductive efficiency of cattle (Bagley, 1993; Diskin et al., 2003); therefore, beef females should be managed for optimal nutritional status. Moreover, under and over nutrition are perceived by the organism as an insult to its homeostasis, which is the classical definition of stress (Moberg, 2000). In turn, stress also directly impairs reproductive efficiency in cattle, with stressors originated from environmental sources (i.e. dietary change, shipping) as well as the individual animal (i.e. excitable temperament).