A modified management intensive grazing system: Effects on pasture plants and pastured dairy cows

Biodiversity may confer several important benefits to grassland agroecosystems. During the first two years of a five-year study, a management intensive grazing system was modified to increase sward heterogeneity and possibly biodiversity. Three levels of grazing management intensity in a randomised complete block design were: intensive management, semi-intensive management, and extensive rotational management. There was also a fourth, non-randomised, delayed grazing management. Sward nutritive quality and grazing utilisation were greatest in the intensive and semi-intensive management treatments. Biomass accumulation was highest in the extensive rotational treatment. No differences in plant biodiversity were observed among management treatments. Few differences were observed in milk yields, milk composition, body weight or body score in paired (n = 8) Holstein cows. One group grazed only the intensive and semi-intensive treatments, while the other grazed all treatments. Behavioural observations showed no grazing preference among management treatments. The biodiversity-supporting management modifications did not negatively affect the sward or pastured dairy cows.