Direct and indirect effects of climate and vegetation on sheep production across Patagonian rangelands (Argentina)

Abstract

Extensive sheep production is an important agricultural industry in the Patagonia region of Argentina, where the most important production metric is the effective lambing rate of the sheep (L%). Climate factors can affect sheep production in two ways: (i) directly on the survival of the lamb, and (ii) indirectly by determining the start of the growing season, aboveground net primary productivity (ANPP) and the availability of forage. The aim of this study was to determine the relationships between climatic variables and vegetation attributes as the major drivers of sheep productivity (ewe live weight pre-mating (ELW) and effective lambing rate (L%)), using structural equation modelling. We observed that precipitation in late autumn/winter and vegetation productivity in late spring/summer were the main drivers and were positively associated with ELW. The ELW was highly and positively correlated with L%. Additionally, the maximum temperature in late spring showed a strong direct and negative relationship with L%. These results indicated that ELW should be taken into account when modelling L%. Regional Patagonian climate change models predict, for the next century a decrease in precipitation and an increase in temperature. Thus, according to our findings, sheep production systems would be affected by a decrease in primary productivity, as well as ELW and L% since these variables are positively associated with precipitation and negatively with temperature. The use of strategic supplementation to meet nutrient requirements and protection from climatic stressors during physiologically demanding production stages of pregnancy and lactation through additional shelter and housing for the sheep could mitigate the effects of climate change by having a positive effect on L% and, therefore, on the total farm income.