Partial replacement of ryegrass and clover herbage with chicory to alter urination behaviour and soil nitrogen loading of grazing dairy cows

Abstract

Chicory (Chicorum intybus L.) is a high moisture, low fibre forage, traits that have been identified to influence protein degradation and urea metabolism. Our recent study revealed that sole diets of chicory increased urinations and diluted the concentration of nitrogen in the urine. The purpose of this study was to compare the effect of feeding a lesser proportion of chicory in the diet, and the impact of the diurnal changes in chemical composition of chicory on urinations and urinary nitrogen concentration. Thirty-six dairy cows were evenly divided into nine groups, and randomly allocated either ryegrass/white clove only (RGWC), ryegrass/white clove plus morning allocation of chicory (CHAM) or ryegrass/white clove plus afternoon allocation of chicory (CHPM). Chicory inclusion increased urinations by up to 69%, resulting in a 33% mean decline in UN concentration, independently of time of allocation. While farmers are encouraged to adopt mitigation strategies to reduce urinary N losses, there is value in offering a range of forage options to improve adoption. These results show that low moistures forages including chicory have the potential to reduce nitrogen leaching through changes in urination behaviour and urinary nitrogen loading.