Effect of Previous Experience on Grazing Patterns and Diet Selection of Brangus Cows in the Chihuahuan Desert

The ability to adapt to different critical environments is critical when livestock are moved because of drought or other management considerations. The impact of previous experience oil grazing patterns and diet selection of Brangus cows in desert conditions was evaluated. Cows originating from a hUmid-subtropical environment (Leona, Texas) were brought to the Chihuahuan Desert (naive) and evaluated against cows that spent their life in the Chihuahuan Desert (native) and cows that were born and raised in the Chihuahuan Desert but were moved to Leona, Texas during the preceding 3 yr (tourist). In addition, native cows with recent experience in desert conditions were compared with naive cows and tourist cows that had not been in the Chihuahuan Desert for at least 3 yr. All cows were mature and had similar pedigrees (n = 21). Cows from the three groups were tracked in three extensive pastures (> 1000 ha) for three 8-10-d periods during winter, early summer, and later summer. Cows never grazed ill the experimental pastures before the study, but native and tourist cows had grazed adjacent pastures. Fecal near-infrared spectroscopy was used to estimate diet quality. Naive cows used 335 ha +/- 83 standard error (SE) less area (P = 0.06) and were 479 m +/- 105 SE closer to water (P = 0.03) than cows born and raised in the Chihuahuan Desert (native and tourist cows pooled) when first evaluated in winter. After pooling all data, native cows were farther (P = 0.06) from water (730 m +/- 283 SE) and spent less time at water (1.0.53% +/- 3.93 SE) than cows that did not spend their entire life in the desert (naive and tourist pooled). During winter and early summer (drought conditions), naive cows selected diets with lower (P < 0.05) crude protein (CP) than cows born in the desert, but during late summer after abundant precipitation naive cows selected a diet with higher (P = 0.07) CP. Although Brangus cows are highly adaptable, animals raised in nearby pastures appear to have advantages over naive animals when grazing Chihuahuan Desert rangeland.