31 March 2000

Big milk yields need not call for high use of concentrates

YIELDS of 7500 litres can be achieved in a variety of production systems, and the most economic is likely to vary from farm to farm.

The finding comes after one year of a study which fed high merit cows on four different diets at the Agri-cultural Research Institute of Northern Ireland, Hillsborough, Co Down.

"The study shows you do not necessarily have to feed 2.5t of con-centrate; you can achieve a 7500-litre yield with 1t of concentrate," said the Institutes Conrad Ferris.

"Costings for the trial indicated a similar margin/litre and margin a cow across the four diet groups."

Each diet was based on grass silage and grazed grass and was fed to 20 November-calving cows. Two groups were fed high quality grass silage and 6kg of concentrate in winter. One of these was grazed from late February to October and the other from April. The other two groups were fed a mix of medium quality silage and 12.5kg of concentrate a day in winter, with one group grazing for an extended season and the other from April.

"But margin a hectare was higher on the high concentrate system, which requires less land."

The choice of most economic system for any farm is likely to depend on its input costs, level of management, labour and land available.

Replacement rate and fertility are also to be examined in the trial. &#42

Dairy cow performance on four diets

A B C D

Concentrates (kg DM) 8,57 1,279 1,627 2,050

Silage quality High High Medium Medium

Turnout date Feb Apr Feb Apr

Milk yield (kg) 7,365 7,490 7,363 7,640

Yields of 7500 litres are achievable with 1t of concentrates, says Conrad Ferris.