PSX-A-6 Late-Breaking: Conventional vs Heritage cattle supplement intake, weight-gains, and body condition scores on Chihuahuan desert pasture

Use of adapted beef cattle biotypes is gaining momentum as a novel management strategy for limiting the environmental footprint of ranching and adapting to climate change in the southwest. We compared supplement intake (SI), calf birthweights, cow weights, and body condition scores (BCS) of desert-adapted Brangus (BR; n = 15) vs. Raramuri Criollo (RC; n = 28) cows in four adjacent pastures (1098±85 ha) for three months (Mar 7 – Jun 9, 2020) using ANOVA for a RCBD (significance at P < 0.05). Cows had ad libitum access to 18% crude protein lick tubs in all pastures, which were weighed weekly to determine SI. Brangus cows had greater SI than RC, both overall (BR: 0.21±0.04 vs. RC: 0.08±0.03 kg×cow×d-1) and on a metabolic bodyweight basis (BR: 2.31±0.09 vs. RC: 0.95±0.09 g×kg0.75). All cows were bred to Brangus bulls and calf birth weights were not different between biotypes (BR: 31.5 ± 1.0; RC: 29.6±0.9 kg). Brangus cows weighed more at the beginning (535.0±14.8 kg) and end (582.2±14.5 kg) of the study compared to RC (beginning: 345.5±11.8 kg; end: 357.0±12.0 kg). Percent of bodyweight change was not different between biotypes (BR: 8.51±2.35; RC: 2.85±1.81 %). On a 1 to 5 scale, BCS of Brangus (4.06±0.09) was greater than RC (3.18 ± 0.07) at the onset of the study, but biotypes had similar BCS at the end of the trial (BR: 4.09 ± 0.09; RC: 3.89±0.08). Our preliminary results indicate that lighter RC cows were capable of gaining bodyweight and improving BCS with reduced SI, both overall and on a metabolic bodyweight basis. This finding may reflect lower nutrient requirements, better relative efficiencies and lesser grazing impacts on desert rangelands by RC cattle. Future studies will seek to replicate these breed-comparison trials over multiple years, research sites, and supply chains, with an emphasis on overall systems production efficiency and sustainability.

Palynological evidence from a sub-alpine marsh of enhanced Little Ice Age snowpack in the Marrakech High Atlas, North Africa

The grazing lands of the High Atlas are vulnerable to climate change and the decline of traditional management practices. However, prior to the mid-20th century, there is little information to examine historical environmental change and resilience to past climate variability. Here, we present a new pollen, non-pollen palynomorph (NPP) and microcharcoal record from a sub-alpine marsh (pozzine) at Oukaïmeden, located in the Marrakech High Atlas, Morocco. The record reveals a history of grazing impacts with diverse non-arboreal pollen assemblages dominant throughout the record as well as recurrent shifts between wetter and drier conditions. A large suite of radiocarbon dates (n = 22) constrains the deposit to the last ~ 1,000 years although multiple reversed ages preclude development of a robust age-depth model for all intervals. Between relatively dry conditions during the Medieval period and in the 20th century, intervening wet conditions are observed, which we interpret as a locally enhanced snowpack during the Little Ice Age. Hydrological fluctuations evidenced by wetland pollen and NPPs are possibly associated with centennial-scale precipitation variability evidenced in regional speleothem records. The pollen record reveals an herbaceous grassland flora resilient against climatic fluctuations through the last millennium, possibly supported by sustainable collective management practices (agdal), with grazing indicators suggesting a flourishing pastoral economy. However, during the 20th century, floristic changes and increases in charcoal accumulation point to a decline in management practices, diversification of land-use (including afforestation) and intensification of human activity.