Dry matter yield, pasture quality and profit on two Waikato dairy farms after pasture renewal

A planned approach to pasture renewal is recommended for improved feed supply and animal production. From 2006-2010 measurements of pasture dry matter (DM) yield and quality were made on two Waikato dairy farms, where pasture renewal was implemented.

These measurements were to determine if extra DM and feed quality resulted. In each case, weekly and/or monthly measurements included comparisons with older, established pastures on the same farm.

On a research farmlet, with a majority of renewed pasture less than 3 years old, an additional 2.1 t DM/ha (+11%) of pasture was measured compared with another benchmark farmlet without renewal for a decade.

On a commercial dairy farm, 2 years of monthly cuts of pastures, representing four different stages of the Programmed Approach™ to renewal, showed a DM yield advantage of 4% and feed quality advantage of 7%, generating, according to UDDER modelling, additional profit of more than $900/ha/yr.

In study one, evidence of extra feed being available to the herd is supported by extra milk production over 3 years compared with the benchmark farmlet. After allowing for contributors to additional milk production other than pasture renewal, (eg maize silage feeding), it was estimated that an additional 151 kg MS/ha was produced from an extra 1.7 t DM/ha resulting from pasture renewal.

A limitation of both studies was the short measurement period (2 or 3 years), insufficient to determine the rate at which the benefits of pasture renewal diminish over time. This is important because under the programme implemented in study 2 it would take 10 years for the whole farm to be re-grassed.

Planned renewal of pastures produced additional higher quality pasture on both farms over a 2 and a 3 year period, compared with non-improved pastures. While it appears likely that pasture renewal was a contributing factor to this increase, limitations to the project design prevent the conclusion that increased pasture energy yield is a certain result from pasture renewal.

For further information please contact Chris Glassey of Dairy NZ directly

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