Effects of Sward Height and Season on Herbage Intake of Strip-grazed Dairy Cows

Abstract Herbage intake by strip-grazed dairy cows was estimated, using chromic oxide as marker, during experimental periods covering different parts of the grazing season, different sward heights and different years. Herbage mass, herbage composition and the milk yield, live weight, lactation week and age of experimental animals were also registered with the objective of including those variables that were significant in a model for studying the influence of sward height and season on herbage intake. Pastures were grazed when planned target sward height was obtained. Average sward height over all experimental periods was 15.0 cm (range 7.4-21.2). The grazing season was divided into early season (May 17 to June 19), mid-season (June 20 to July 31) and late season (August 1 to August 20). The data comprise herbage intake measurements on 69 dairy cows with an average milk yield and live weight of 15.6 kg/day and 546 kg, respectively. Pasture allowance was 30 kg dry matter/cow and day. The content of metabol...