Silage in a silo measures 33 metres long by11 metres wide with an average depth of 2.1 metres. What tonnage of silage is in the pit?
Silage in a silo measures 33 metres long by11 metres wide with an average depth of 2.1 metres. What tonnage of silage is in the pit?

Calculate your forage requirements: Although there should be plenty of silage on farms, it is still a good idea to estimate the tonnage of silage available and compare this with your likely winter demand.

Use the tables below to estimate supply and demand on your own farm.  

As an example silage in a silo at Greenmount Campus measures 33 metres long by 11 metres wide with an average depth of 2.1 metres. What tonnage of silage is in the pit?

To calculate the volume of silage, multiply 33 by 11 by 2.1. This equals 762 cubic metres.  

Table 1: Conversion factors to convert silage volume to tonnes of silage

Silage dry matter (%) Tonnes of silage per cubic metre 20 Multiply by 0.77 25 Multiply by 0.68 30 Multiply by 0.60 Whole crop 40% dry matter Multiply by 0.67 Forage maize 30% dry matter Multiply by 0.75

To convert the volume of silage to fresh weight multiply the volume by the correct conversion factor. For our example, assuming the dry matter is 25 per cent, multiply 762 cubic metres by 0.68. This equals 518 tonnes of fresh silage.

Table 2: Estimated monthly feed requirement of stock (assuming 25 per cent dry matter silage)

Livestock Silage (tonnes per month) Dairy cow in milk 1.4 Dry cow 0.9 0-1 year old heifer 0.6 1-2 year old heifer 0.9

To estimate the demand for silage multiply the number of each class of stock by the number of months to be fed. For example, 9.8 tonnes of silage is needed to feed one milking cow for seven months (1 cow x 1.4 tonnes x 7 months).

If you are short of forage consider your options now by reducing requirements or sourcing extra supplies.

Planning for early grass next spring

Late season ground conditions and grass growth have been good on most farms. As this is probably the last rotation before housing, action taken now will effect early grazing next spring. The timing of paddock closure and residual grazing heights determines the start date for grazing and grass quality next year.

Paddocks closed now will be the first to be grazed in spring. Do not graze paddocks again even if there is good grass growth in October and November. Paddocks should be grazed to 5 cm or less on a rotational basis and closed for the winter.

Paddocks closed in late November will not have sufficient grass for grazing until the end of March or April next year.

Colostrum for calves

Colostrum management is the single most important factor determining calf survival and subsequent health. Calves are born without any immunity and rely on the protective effect of antibodies derived from their mother’s colostrum. They must get enough quality colostrum as quickly as possible after birth. Protection is achieved by ensuring the new born calf receives 10 per cent of its bodyweight or 3.5 to 5 litres of colostrum within the first hours of birth. If a calf does not suck quickly carry out stomach tubing to ensure it is properly protected.

Typical September performance

How does your farm compare with the typical performance from the Co Armagh farms I work with:

Average daily milk yield 20.4 litres per cow Average daily concentrate fed 5.7 kilos per cow Average daily milk from forage 7.5 litres per cow Average daily concentrate feed rate 0.28 kilos per litre

If enough quality grass is available grazing should maintain 14 litres of production. To support higher yields supplementation will be required. Set your feeding for 0.45 kg per litre above 14 litres. If grass is in short supply 10 kilos of fresh silage will replace 2.5 kg of grass dry matter or about a fifth of a cows daily grass intake.

Date to remember

Remember under the Nitrates Action Programme 15 September is the last day for sowing chemical nitrogen fertiliser.