27 March 1998

Early two-hour turnout gives a big lift to yields

Spring grazing benefits,

boosting silage intakes and

effect of breed on ewe

colostrum were key topics at

this weeks British Society

of Animal Science

conference in Scarborough.

FW Livestock team reports

BIG increases in both milk and protein yields occur when dairy cows are turned out early on to spring pasture for two hours a day.

Delegates at the Scarborough, Yorks, conference heard that higher yields were obtained even when silage, offered indoors, was restricted and cows grazed the sward down tightly to a residual height of 40mm.

Evidence comes from the Agricultural Research Institute of Northern Ireland, where scientists Sinclair Mayne and &#42 J Sayers studied the effects of grazing severity and/or degree of silage restriction during the indoors feeding period on the response to extended grazing.

Forty spring-calving Holstein Friesians, all offered 6kg of concentrates a day, were subjected to five treatments from Mar 7 to Apr 17.

These included cows offered grass silage ad lib and kept indoors; cows offered silage ad lib and turned out for two hours to graze perennial ryegrass down to a height of 55mm; silage ad lib and two hours grazing with the sward taken down to 40mm; silage access restricted to 80% of ad lib before two hours grazing down to 55m and restricted silage followed by two hours grazing with grass taken down to 40mm.

Silage intakes were significantly lower, with all grazing treatments with this effect being greater with the more lax grazing treatments and reflecting increased herbage intake. Milk yield was increased significantly with the grazing treatments and there was no significant effect of silage restriction on grazing severity.

There were no treatment effects on milk fat or protein concentration and consequently milk protein yields were significantly greater with the grazing treatments. Effects on cow liveweights were inconsistent with animals losing weight on two of the grazing treatments.

Grazing dairy cows for two hours a day in early spring lifts milk and protein yields… Sinclair Mayne.