1. Sokoine University of Agriculture Official Publications

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Browsing 1. Sokoine University of Agriculture Official Publications by Author "Estell, Richard E."

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    The use of a heritage cattle breed as an adaptation strategy to new challenges imposed by climate change in Chihuahuan desert rangelands in the Southwest United States
    (Rangeland Society of Tanzania (RST), 2023) Nyamuryekung’e, Shelemia; Cibils, Andres F.; Estell, Richard E.; Utsumi, Santiago A.; McIntosh, Matthew M.; Spiegal, Sheri
    This review synthesizes research comparing conventional (Angus X Hereford; AH) vs. heritage (Raramuri Criollo; RC) cattle foraging behavior, heat tolerance, and cow-calf interactions using telemetry devices in the context of determining adaptation strategies related to climate change effects. The AH and RC cows grazed separately in two adjacent pastures in a crossover design during summer and winter for three consecutive years. Rectal fecal samples were collected twice (day 14 and 28) in each experimental period and fecal-DNA (fDNA) meta-barcoding analyses were performed to characterize diet compositions. A subgroup of individuals in each herd was fitted with sensors to track their location (GPS collars), body temperature (iButton thermal loggers), and cow-calf contact events (proximity loggers). The RC cows traveled farther, spent less time resting, more time grazing, and explored larger areas than AH cows. The RC cows showed a stronger preference for ecological patches with greater shrub density and avoided areas with a high density of black grama (an ecologically sensitive forage species) during winter (period when vegetation is most vulnerable). Our fDNA study revealed that RC cows select less black grama and more mesquite than their AH counterparts, which corroborated our vegetation electivity findings. During summer, RC cows maintained a lower internal body temperature than their AH counterparts, providing evidence of heat tolerance in RC. The RC calves appeared to impoVe feZeU conVWUainWV on WheiU damV¶ moYemenW paWWeUnV; nursing RC dams covered a daily grazing area almost three times larger than AH dams. Differences in foraging strategies documented in this review support our hypothesis that RC (heritage breed) cattle are better equipped to cope with hotter and drier climates and are better able to adjust their grazing behavior according to forage availability.