2008 Joint Annual Meeting (5-9 Oct. 2008): Behavior of Cattle Grazing Adjacent Monocultures of Tall Fescue and Alfalfa.

The use of adjacent monocultures of different forages is a valuable tool to evaluate dietary choice of livestock by minimizing constraints of searching for preferred forages which occurs in mixed swards. The distinction between active selection and grazing randomly can be achieved by offering forages in different proportions of ground area. In 48 hour periods, a 4x4 Latin Square design was used to evaluate behavior of beef steers in treatments that varied by ground area proportion of endophyte-free tall fescue (FES, Festuca arundinacea Schreb.) and alfalfa (ALF, Medicago sativa subsp. sativa L.). Treatments were, 25:75, 50:50, and 75:25 of FES to ALF, respectively, and 100% FES with 0.7 ha/ treatment and 4 day minimum between periods. Each steer (n=12, IBW=574±14 kg, 28 months old) was fitted with a Global Positioning System (GPS) tracking device to determine in which forage the steers were located, and a pedometer that recorded number of steps and time spent standing, active, and lying. There was no difference (P≥0.13) in percent time spent standing or lying among treatments (100% FES= 40, 54%; 25:75= 54, 41%; 50:50= 52, 42%; 75:25= 52, 41% of day standing and lying, respectively). Steps taken were similar (P≥0.28) among FES: ALF treatments (2556, 2757, and 2882 steps/day for 25:75, 50:50, and 75:25, respectively) but cattle took fewer (P≤0.02) steps/day (2006) when they had only FES to graze. Cattle grazing 100% FES were less (P≤0.007) active/day (3.8%) than those in FES: ALF treatments (25:75= 4.9%; 50:50= 5.4%; 75:25= 5.6%). Steers spent more (P≤0.02) minutes/day active in ALF than FES (25:75= 521:106; 50:50= 413:274; 75:25= 453:162, minutes/day in ALF: FES, respectively). Similarity in daily activity among cattle in FES: ALF treatments suggests that cattle did not move randomly between forage types by the proportion of ground area, but actively selected where to graze.