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

Abstract

Chicory (Chicorum intybus L.) is a high moisture, low fibre forage with the potential to alter urinary nitrogen (N) excretion. The following study compared the effect of replacing ryegrass/clover (Lolium perenne L./Trifolium repens L.; RGWC) with chicory in the diet, and the impact of diurnal changes in composition of chicory on urination frequency and volume and nitrogen (UN) concentration. Thirty-six, mixed-age dairy cows in 2nd to 4th parities were stratified according to days in milk (155 ± 3.3 days), body weight (483 ± 13.8 kg) and milk yield (21.3 ± 0.97 kg/cow/day) and assigned to one of three diets. The diets were either RGWC, RGWC replaced with 50% chicory either in the morning (CHAM) or in the afternoon (CHPM). Chicory inclusion increased urination frequency by up to 69%, with a 33% decline in UN concentration, independent of time of feeding. The ratio of non-structural carbohydrates to protein was greater for CHPM compared with CHAM or RGWC diets, though offering chicory in the morning was more likely to reduce urinary N loss. High moisture forages such as chicory can be used to reduce urinary N load by increasing the spatial distribution of urine from cows.