Foraging behavior of Raramuri Criollo vs. commercial crossbred cows on rangelands of the southwestern United States and Northern Mexico

Abstract

Matching livestock genetics to climatically variable and nutritionally challenging environments is critical to the success of livestock ranching in the Southwest US, Northern Mexico, and arid rangelands elsewhere. We compared foraging behavior patterns of Raramuri Criollo (a heritage breed) and British beef cows at the Jornada Experimental Range (JER) in southern New Mexico, USA, and Rancho Experimental Teseachi (RET) in central Chihuahua, Mexico, during spring and fall of 2005. The study design comprised four animal monitoring weeks per site and season and each animal monitoring period consisted of four replicates, each of which included a set of six mature cows per breed equipped with a GPS tracking collar. GPS-derived movement, activity, and vegetation use variables were analyzed by sets of mixed models considering the fixed effects of breed, site, season, and all interactions (significance; P < 0.05). Compared to the British cows, Raramuri Criollo counterparts traveled further and grazed across larger areas of flat desert rangeland at JER and explored and grazed higher elevation rangelands with steeper slopes at RET. Breed differences were greatest when forages were dormant or scarce. Similarly, habitat use differed by vegetation class and breed with British cows spending more time in open grassland areas dominated by palatable herbaceous plants at JER and RET. Breed differences observed in this study likely reflected the outcomes of natural (Criollo) vs. artificial (British) selection pressure through time. Foraging behavior traits observed in Raramuri Criollo cows could be critical for adaptation of cow-calf production systems of the region to increasingly variable foraging environments caused by climate change.