High-index herd high in table
THE Grins family run farm is said to be typically Dutch, but its high genetic index dairy herd is far from the 7500kg national average yield.
The 100-cow herd averges 9500kg, at 4.45% fat and 3.50% protein, ranking it high in the Dutch production listings.
"In the early 1980s we introduced index breeding for milk production and use Holstein sires over the herd," says Piet Grin of Kolhorner Farm, Biddinghuizen. His 52ha (130-acre) mainly all-grass farm includes 17ha (42 acres) of forage maize.
Bull selection is based on Dutch INET value (the economic index for milk, fat and protein) and udders, legs and feet. The chosen bulls are used almost exclusively for up to six months, if the progeny milk well a bull will be used again, says Mr Grin. Current sires include Jabot, Celsius, Labelle and Sunny Boy.
One dam line, Frona, now dominates the herd accounting for a third of the cows. "The original Frona cow has now retired from production but still lives on the farm, and several of her sons have been progeny tested."
Feeding management is critical for performance on the twice-daily milked herd. Cows graze from May to August and are zero-grazed one month either side of this.
"Zero-grazing uses the grass more efficiently at these times. We also zero-graze cows in hot weather to keep feed intakes and yields up," he claims. In addition cows are offered 4.5kg dry matter (DM) of maize silage a cow and 2kg DM of potato chip residue a cow a day. Concentrates are fed to yield in the out of parlour feeders.
Cows are fed 7kg DM maize silage, 7.5kg DM grass silage, 2kg DM potato residue and 2kg a cow a day of a soya-based parlour concentrate.
In addition a 25% crude protein concentrate is fed to yield up to a maximum of 9kg a cow a day in out of parlour feeders. "After 180 days in milk, the ration is cut to 2kg of high crude protein concentrate in the parlour."