Grazing management practices on Waikato and Canterbury dairy farms diverging in bulk milk urea content

Authors

DOI:

https://doi.org/10.33584/jnzg.2023.85.3649

Abstract

New Zealand dairy farmers have little realtime information on surplus nitrogen (N) in their herd’s diet to help manage farm-scale N loss. By understanding the influence of management on bulk milk urea (BMU), farmers could potentially use milk components to identify changes in dietary N surplus. Our study examined the relationships between grazing management and BMU concentration on 38 dairy farms selected for low or high BMU in Canterbury and Waikato. Measurements included pre- and post-grazing herbage mass, perennial ryegrass leaf stage at grazing, and botanical and chemical composition (crude protein (CP) and metabolisable energy (ME) content) of herbage on four occasions over a year. Herds with Low BMU tended to graze pastures with a greater pre-grazing herbage mass (+153 kg DM/ha), a more advanced leaf stage (+0.13 number of leaves), and longer grazing intervals (+11 days). Consistent with this, herbage on Low BMU farms had lower CP (-2.7%) compared with High BMU farms. We identified grazing management differences between Low and High BMU groups, which could be linked to reductions in N surplus in the herd’s diet through the lower CP% of pasture offered. Future work should determine the importance of this in relation to other farm management factors such as
supplement and N fertiliser use.

Downloads

Download data is not yet available.

Downloads

Published

2023-11-10

How to Cite

Glassey, C., Woods, R., Reed, C., Puriri, N., Scott, G., Hodgkinson, A., & Bryant, R. (2023). Grazing management practices on Waikato and Canterbury dairy farms diverging in bulk milk urea content. Journal of New Zealand Grasslands, 85, 275–283. https://doi.org/10.33584/jnzg.2023.85.3649

Issue

Section

Vol 85 (2023)

Categories

Most read articles by the same author(s)