Pond Water Quality for Livestock in Southwestern Iberian Rangelands

ABSTRACT

Construction of small ponds that collect and store rainwater to be used for livestock watering has been one of the most widespread adaptive solutions in Iberian rangelands to cope with water scarcity, a problem that has become particularly relevant in recent decades due to the progressive increase in livestock density on farms. However, watering ponds can also be a source of health problems due to the consumption of low-quality water by livestock. In this study, we analyzed the physico-chemical and microbiological quality of water from a set of watering ponds located in Iberian rangelands and evaluated its suitability for livestock consumption by comparing the analytical results with internationally recognized water standards for livestock. In addition, seasonal and spatial variations in pond water quality and the influence of some physical and managerial factors were assessed by multivariate statistical analysis. Results showed a high seasonality in pond water composition. The quality of pond water was sufficient to be used for livestock during the rainy season, but high bacterial pollution of fecal origin was evidenced at the end of the dry season in many ponds, with consequent risk for animal health. Dilution by rainwater and evapo-concentration processes were the main mechanisms that determined the concentrations of contaminants in pond water, while livestock density did not seem to have a significant influence. We propose some strategies, such as diversification in water supply sources and regular water quality testing, that farmers could adopt to deal with the detected water quality problems.