Many rangelands in the southwestern United States have experienced increased shrub cover and lower and more variable forage resources during the past 100 years. Criollo cattle are descendants of cattle brought to the Americas by European explorers that spread throughout North and South America. These cattle were displaced in many areas as British breeds became popular, but isolated populations remained that had undergone natural selection for nearly 500 years. Scientists at the Jornada Experimental Range in Las Cruces, New Mexico introduced Raramuri criollo genetics from the Tarahumara region of Chihuahua, Mexico to the research herd about 15 years ago in an effort to capitalize on their ability to thrive in harsh landscapes of the Chihuahuan Desert. They hypothesized that this smaller framed animal might be more suited to extensive shrubby landscapes and exert a lower environmental footprint than cattle of European descent. Preliminary observations during the early years of this project suggested that behavioral characteristics of this biotype could potentially be used to improve utilization of extensive rangelands with restricted water distribution. Raramuri criollo generally traveled farther per day and farther from water than Angus x Hereford crossbreds typically raised on these rangelands. Approximately five years ago, the Jornada expanded this program by joining forces with scientists from New Mexico State University, Mexico, and South America. Several studies were initiated that encompassed aspects of behavior, distribution, habitat and ecological site use, maternal behavior, diet selection, heat tolerance, and performance of Raramuri criollo cattle. Many of the results from these collaborations are reported in this special issue.

在过去的 100 年里，美国西南部的许多牧场都经历了灌木覆盖增加和草料资源减少和变化更多的情况。克里奥罗牛是由欧洲探险家带到美洲的牛的后代，这些牛遍布北美和南美。随着英国品种的流行，这些牛在许多地区流离失所，但经过近 500 年自然选择的孤立种群仍然存在。大约 15 年前，新墨西哥州拉斯克鲁塞斯的 Jornada 实验范围内的科学家将来自墨西哥奇瓦瓦塔拉乌马拉地区的 Raramuri criollo 遗传学引入研究群，以期利用它们在奇瓦瓦沙漠的恶劣景观中茁壮成长的能力。他们假设，与欧洲血统的牛相比，这种体型较小的动物可能更适合广阔的灌木丛景观，并且对环境的影响较小。该项目早期的初步观察表明，这种生物型的行为特征有可能用于改善水资源分配受限的大片牧场的利用。与通常在这些牧场上饲养的安格斯 x 赫里福德杂交种相比，Raramuri criollo 通常每天旅行更远，离水更远。大约五年前，Jornada 通过与来自墨西哥和南美洲的新墨西哥州立大学的科学家联手扩大了该计划。发起了几项研究，涵盖行为、分布、栖息地和生态场地使用、母性行为、Raramuri criollo 牛的饮食选择、耐热性和性能。本期特刊报道了这些合作的许多成果。