11 April 1997

High yielders can fulfil potential if grass is managed

By Jessica Buss

MANAGEMENT of grass and forages must encourage higher feed intakes if the high genetic merit cows of the future are to be managed on a high forage diet.

Speaking at the Genus Nat-ional Forage Conference, Sinclair Mayne of the Hillsborough, Agricultural Research Institute of Northern Ireland, warned that modern £85 PIN cows can average over 35 litres a day at turnout. The 32.5-litre cow must eat 19kg of grass dry matter to support that yield without concentrates, but current intakes of grazed grass are 15-17kg DM.

The correct sward cover after grazing for maintaining sward quality fails to allow these high yielders to achieve maximum grass intakes, he explained.

"Rotational grazing is the only way to present forage to these cows, but more grass will have to be left behind after the field is grazed. Moving to a leader-follower system makes harvesting the grass a lot easier for the high yielder. Young or dry stock, or cutting after every second grazing could then be used to tidy the sward."

Dr Mayne also said that silage must be high in energy and well fermented for high intake potential. A good silage could save £10,000 through increased performance and reduced concentrate use for a 100-cow herd over a 100-day winter.

"To achieve high quality silage this year crops may need cutting before the end of April, if good weather continues, as grass is three weeks ahead of average years."

"Ensiling technique is the most important factor – including rapid clamp fill, minimal soil and slurry contamination, good consolidation and rapid sealing.

Sinclair Mayne: More grass will have to be left behind after grazing to secure intakes needed by high yielding cows.


&#8226 Rotational grazing essential for high intakes.

&#8226 Silage must have high intake potential.

&#8226 Managing on high forage diets will be challenging.