17 November 1995

Diet of grass is never enough

EXPECTING too much from grass means some producers are using 1960s management to exploit the genetics of the late 90s.

The claim, from New Zealand veterinary surgeon Sue Macky, was made at Carmarthen in Dyfed, at the first of a series of nutrition conferences organised by complete feeding specialist Keenan.

Dr Macky said that more farmers in her home country were moving away from complete reliance on grazed grass, because they now accepted grazing was not nutritionally dense enough to provide everything high genetic merit cows needed to express their yield potentials.

High land costs of £10,000/ha and milk prices between 9p and 12p/litre, meant producers had realised they must try to improve profits by greater production efficiency. One way was to invest in genetics, but this could not be achieved through traditional reliance on extended grazing, which occasionally became a type of controlled starvation.

"New Zealands top producers now agree that they must have more control, and this means providing supplementation."

Cows needed a daily dry matter intake in excess of 4% of their body weight. This was not always possible from grass alone. Properly balanced rations could improve forage utilisation, milk composition, cow health and fertility.

One producer using supplements improved profit by over 40%, while that of neighbouring farms fell by 10%. This was achieved by a 24% increase in yield, and a 35% rise in total solids production.

With strong interest in extended grazing in the UK, Dr Macky urged producers to be aware of all the variables that could affect grass utilisation and dry matter intake. These included climate, the palatability, length and density of the sward, and the varieties it contained, the number of days between grazings, and grazing time. &#42

Milk producers in New Zealand believe grazed grass does not provide everything the high genetic merit cow needs to express her yield potential.