5 July 2002


Following the success of a

herdspersons study group

in Wales, a similar West

Country group has been set

up and recently held its

third meeting at the farm

where one of the group

members works.

John Burns went along

EVER wanted to know how to calculate grazing allocations, but been too afraid to ask? This and many more questions were answered as herdspersons got together on one Wilts unit.

The West Country Herdspersons Development Group meets as often as members want, which is likely to be six or seven times a year. Members are from Devon, Somerset, Dorset, and Wilts.

Meetings are carefully structured to achieve clear objectives, but thanks to the experience and skill of consultant Debbie Kinder, those objectives are achieved in a relaxed atmosphere.

The groups third meeting, held in mid-June, was at the Riders Horton House Farm, Devizes, hosted by herdsman Allan Bailey.

Members were asked a series of questions about their herds and grassland. These included yield of milk solids a cow a day, average grass cover on the farm, grass growth rate and percentage non-return rate. The group then discussed the benefits of a tight calving pattern before moving to grazing paddocks.

In the first paddock, which the herd had finished grazing several days before, group members visually estimated the grass cover at 1850 to 1950kg DM/ha. Checks with the plate meter suggested it was nearer 2000kg.

During discussions, the group agreed target residual grass cover – whats left after grazing – should be 1600 to 1750kg DM/ha. "It has been exceptionally wet season with frequent periods of torrential rain. So more grass than usual has been muddied and cows have refused to clear it all up," explained Mr Bailey.

Mrs Kinder then guided the group through a calculation to estimate what grass cover would be in 11 days time when the herd would return to the paddock. At 60kg DM a day growth rate, there would be an additional 600kg DM after 10 days growing, giving a total of 2600kg/ha. That was close to the maximum of 2700kg/ha she recommended for grazing.

If growth rate proved higher than 60kg a day, taking grass out of the grazing rotation either by mowing for silage or hay, or leaving it for grazing later, if dry weather was expected, would help reduce grass cover, said Mrs Kinder.

But she advised against deferring grazing on farms unlikely to dry out or where stocking rate was low. "This could lead to grass accumulating and quality would rapidly decline. Where deferring is appropriate, give one feed a day of good grass and one feed of lower quality deferred grazing."

She warned against wasting money making small amounts of surplus grass into big bale silage for feeding during a dry spell, possibly only a few weeks later.

To producers concerned that deferred grass would go to seed, she assured them it would not do so after mid-July.

In the next-but-one field, due to be grazed in five or six days time, group members divided into three sub-groups, with a series of questions to answer.

"The herd of 240 Jerseys is averaging 12.5 litres a day, with a total of 50ha of grassland available for grazing. What is the herds daily dry matter requirement and what area of the paddock will meet that need? Also, given the farms target of a 30-day grazing rotation by July 20, how can this be achieved without losing grass quality?" asked Mrs Kinder.

Having given group members the chance to work out their answers, she explained the correct calculation.

"Dry matter requirement is 13kg a cow a day, so 240 cows need 3120kg a day. With 50ha available, each hectare must grow 62kg DM a day – 3120 divided by 50 – over the period if average grass cover is to remain at its present level of 2200kg DM/ha."

With 50ha (123.5 acres) to graze over 30 days, the daily allocation would be 1.7ha (4.2 acres). But it was questionable whether grass would grow fast enough on the farm.

"Average grass growth rate is 80kg/ha/day in late June, 60 in early July, and 50 in late July and August. But grass growth so far this year had been below average," said Mr Bailey.

If grazing alone could not meet the herds needs, then it must be supplemented with concentrates, silage or straw advised Mrs Kinder. "Avoid under-feeding at any stage."

She also explained why the farms grazing plan aimed for a progressive slowing down of the rotation to 30 days between July 20 and Aug 20, 40 days until Oct 1 and 60 days for the final grazing of the season. "This farm relies solely on grazing in the autumn and early spring and sufficient stocks of grass must be built up to meet the herds needs."

Moving to look at cow accommodation, group members discussed how a herd increase could be housed without risking cow health and increasing workload.

Suggestions included use of redundant silage bunkers with or without a cheap roof, an electric-fenced hardcore area currently holding machinery or a woodchip corral. More attention to grouping cows according to calving date, so more could be left outside for longer – perhaps on stubble turnips – was also offered as a possible solution. &#42

&#8226 Teach new skills.

&#8226 Assist motivation.

&#8226 Help with problem solving.

Members of a recently formed south-west based discussion group calculate grazing allocations for the host farms Jersey herd.

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