Amount needed key to budgeting
Amount needed key to budgeting
GRASS budgeting is like managing a pit of silage – with the exception that you do not know exactly how much grass you will grow when you turnout, says Christian Fox, herd manager at Crouchlands Farm, Plaistow.
"When grazed grass is half your cows annual diet you need an idea of how much grass is required to get the grazing management right.
"By budgeting for each half monthly period you have more chance of having the grass you need, and feel in control of the grazing." A computer spreadsheet makes the job quicker and easier, he adds.
In 1997, Mr Fox had 200 September-to-November calving cows and 200 youngstock to feed at grass and next summer there will be 300 cows on the 114ha (280 acre) farm.
Yields average 5600 litres a cow from 1t of concentrate, with a feed cost of 6.5p/litre, including concentrates, minerals, forage additives, crop establishment, silage making and feeding out.
Mr Fox would like to lower feed costs further by increasing the proportion of grazed grass in the cows diet above the current 48%. The farms heavy wet soils restrict the grazing season, with turnout usually in mid-March and housing in early November.
But he has already started increasing the grazed grass in the diet since he began grass measurement, budgeting and rotational grazing in March 1996.
His initial feed budget used average grass growth figures, but these were soon updated with those measured on the farm using a plate meter each week to 10 days of the grazing season. Measurments are taken less often in winter, once grazing has finished.
To complete the budget, Mr Fox required information on grass growth rates, average farm cover – the amount of grass available over the grazing area, the acreage being grazed and daily cow intake estimates to work out the required intake a hectare a day and the growth rate needed to support that intake. When grass growth rates are slower than needed to support cow intakes grass cover will fall, explains Mr Fox.
For the spring, Mr Fox can predict the cover needed at the start of the year for his optimum turnout date. Budgeting for grass growth will ensure that turnout is not too early or too late to maintain average farm cover at 1700-2500kg/ha in each half month period on his budget through the year, providing a good supply of grazing.
When actual measured grass growth is below or above the prediction, then adjusting the budget will allow cover to be managed by increasing or decreasing the acreage for grazing or cow numbers by drying off or introducing supplementary feeding at the correct time.
"If we overgrazed in the winter, the budget shows that with too little cover at turnout we would struggle through to the summer when we dry cows off." Too low, in this case, would be about 1400kg/ha, the level which cows would normally graze down to – and much higher than sheep leave swards, he warns. Leaving average cover at 1600 at the end of the grazing season means swards range from 2000 to 1400, giving a range of cover at turnout for rotational grazing.
The budget shows that at the start of the year the cows need 1600kg/ha of cover to give 1950kg/ha by turnout. They will graze once around the farm and then the grazing acreage will be restricted in April to allow a silage cut.
That reduced acreage will see average cover drop on the grazing area but it will remain acceptable at above 1700kg/ha. The silage is still important for autumn calving cows, he adds.
"However, there is no point in making silage and having to feed it two weeks later, either cut less or cut earlier for a faster recovery."
Then through the rest of the summer he will aim to keep grass covers at 2000-2500kg/ha. But in summer cows will be dried off, relieving pressure on grazing. *
INFORMATION NEEDED
• Cow numbers and ave DM intake.
• Average grass cover.
• Grass growth rates.