Project focused on achieving more milk from grazed grass
Even in a difficult season, having a clear focus on grazing
grass to its best possible advantage can be worthwhile.
Jeremy Hunt reports
AIMING to produce more milk from grazed grass and total forage has been successful on one unit over the past three years; even in last years poor grass season which lasted only five months.
The 200-cow dairy herd run at Newton Rigg College at Penrith, Cumbria, has produced almost one-third more milk from forage during a three-year project organised by the Institute of Grassland and Environmental Research. Newton Rigg was one of three sites chosen for the study.
At the peak of the project, in March last year, yield from grazed forage/cow was up by 31.9% based on the rolling average being achieved when the project started in 1998. The yield from all forage/cow increased by 74.7% (see table).
Harry Martin, senior lecturer at the college, has been evaluating the results. "The herd has been producing much more milk/cow from grass and from total forage since the trial started. However, performance figures did slip back because of the poor summer and wet autumn last year.
"By October last year, the increase in milk yield was running at 17.5% and yield from all forage/cow was at 64%. These figures show a marked improvement on our starting point and highlight the benefits of aiming for more milk from both grazed grass and total forage intake," says Mr Martin.
Prior to the trial the herd was managed on a set-stocked system and was achieving an average yield of 7150 litres/cow. One of the first grassland management changes involved setting up a paddock grazing system to provide greater control over grass intakes. Sward height measurements were taken throughout the season to monitor grass growth and availability more effectively, he says.
The herd was split into two groups for grazing. At turn-out, each group comprised 90 cows – the high yielding group was made up of cows giving more than 35 litres/day at that time. All others were managed as low yielders.
As the first grazing season progressed, there was movement between the groups. The high yielding section was reduced to 60 cows, while the low yielding section increased to 120 cows. The status quo gradually returned once calving started in July.
Target yield from grass at turn-out was maintenance plus 20 litres for high yielders and maintenance plus 25 litres for low yielders. Only high yielders were fed concentrates.
By the end of June/early July the target from grass for high yielders was maintenance and 18 litres. Grazed grass was supplemented with silage from early August at a rate of 15-20kg/head offered after milking on an ad-lib basis.
In early September, silage was supplemented with 2kg of sugar beet pulp/cow/day at which point the herd was split into three groups – high, medium and low yielders – prior to winter housing.
"Because of poor weather last autumn, we had cows inside at night from Sept 13 and fully inside by Oct 10. Low yielders stayed out day and night until the end of October, but were offered silage for several weeks prior to full housing," says Mr Martin. *
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• Benefited from defined aim.
• Paddock grazing worthwhile.
• Winter management vital.
College results from start to end of trial
Nov 97 Mar 00 Oct 00
Yield from grazed forage/cow (litres) 1930 2547 2268
Yield from all forage (litres) 2302 4022 3787