Heat recovery unit costings

8 January 1999

Farrowing pen assessment

A £300,000 study is being launched to assess whether the benefits of free farrowing pens outweigh the drawbacks.

The work at CAMBAC will look at sow and piglet performance, mortality, and behaviour to determine whether group farrowing systems – where sows have free access between individual farrowing nests and which are seen as welfare-friendly – can benefit commercial production, says CAMBACs Jane Guise.

The trial aims to provide comparable results from a comprehensive range of free farrowing systems managed with the same staff, feeding and management on one unit, which has not been done before, she suggests.

Two new farrowing houses to be used in the trial will feature part or fully slatted pens; slatted or straw-based solari-type pens; and hinged gate stalls or hinged crates to compare group farrowing in different types of housing, explains Dr Guise.

Litter performance, piglet mortality and labour use will be monitored in the largely MAFF-funded study to judge whether welfare-friendly free farrowing systems can be used widely in commercial practice.


&#8226 SHEEP producers can take advantage of a free analysis service investigating the impact of toxoplasmosis – the second most important cause of abortion – on barrenness in ewes.

The Intervet service, available to unvaccinated flocks of over 250 ewes, involves blood testing first pregnancy ewe lambs or shearlings after scanning. Producers interested in taking part should mark non-pregnant ewes at scanning so they know which to blood-test.

Interested producers should contact their vet, who will blood test six barren and six pregnant ewes for comparison. While there is a charge for blood testing, analysis is free.

&#8226 A NEW £230,000 MAFF sponsored project assessing ammonia emissions from farms it to be undertaken by scientists at the Institute of Grassland and Environmental Research.

The project aims to look at the entire ammonia cycle and find cost effective ways of limiting the release of ammonia into the atmosphere from farms before likely implementation of control measures by the EU.

Confusion rife over land sludge disposal position

By Simon Wragg

CONTROVERSY looms over disposal of sewage sludge on land after the Jan 1 ban on dumping at sea. Producers are being told by some organisations that retailers will accept livestock reared on sewage-treated pasture, while others say retailers wont.

These mixed messages are leaving producers in confusion. While Scottish NFU officials say use of sewage sludge should be regarded with extreme caution, SQBLA dismisses any notion that retailers will find fault with sewage use where applied in accordance to current legislation.

But Scottish NFU policy director Craig Campbell is adamant: "We must urge extreme caution. Its the lack of any indemnity for producers using sewage sludge that they wont be discriminated against that gives cause for concern. Until a retailer code is signed, sealed and delivered producers must be extremely cautious."

SQBLA chief executive Brian Simpson dismisses this: "We have talked to some, but not all, retailers and dont foresee any problems provided legal requirements for handling sewage sludge are met."

South of the border, FABBL is taking the same line, but its chief executive Phillipa Wiltshire suggests meetings will be held with retailers to review the situation. Assured British Meat hasnt yet considered the consequence of sewage disposal on land, but chief executive David Pearce says it could also appear on its agenda.

Common concern surrounds the possibility of sewage sludge transferring bacterial pathogens into the food chain. According to Mike Paine, sewage consultant to NFU, risks include E coli 0157. "Land disposal of sewage sludge can never be regarded as entirely risk free, it will be up to producers to decide if they want to use it."

ADASs Brian Chambers says there are economic reasons to use sewage sludge as a fertiliser. It is often sold treated or digested for a nominal fee of as little at £1/t, yet an application of 125 cubic m/ha (11,000 gal/acre) can provide 150kg N/ha (120 units/acre) and 190kg P/ha (150 units/acre) over a rotation worth up to £94/ha (£38/acre), he says.

Recent industry figures suggest sewage sludge is applied on 80,000ha (197,600 acres) of agricultural land, 40% of which is pasture. But the annual volume of sewage sludge to be disposed is expected to double to 1t million/annum this year.

To pre-empt retailer demands, the water industry and British Retail Consortium – to which all big retailers belong – have agreed that untreated sludge can no longer be applied to grass or silage ground. Digested sludge can be directly applied to silage ground or injected at a depth of at least 15cm (6in) on grazing pasture.

Producers can find guidelines for sewage application in MAFFs Code of Good Agricultural Practice for the Protection of Air, Soil and Water, in an updated Department of Environment, Transport and the Regions booklet and from local authority waste disposal departments.

Despite these guidelines, retailers have yet to collectively and comprehensively give a decision on sewage use. This is forcing Scottish NFU legal and commercial committee convenor Henry Murdoch to warn producers to be wary of spreading sewage on land.

Mr Murdoch told farmers weekly: "Ive already been told by one producer that a quality retailer has threatened to tear up his contract if sewage is spread on the farm." He advises producers at the very least to ask buyers if they will continue to accept stock where sewage is spread.

The Soil Association says that organic farmers are automatically excluded from using sewage sludge.

Sewage Sludge

&#8226 Viewed as cheap fertiliser.

&#8226 No unanimous retail vote.

&#8226 Ask buyers before use.


&#8226 Viewed as cheap fertiliser.

&#8226 No unanimous retail vote.

&#8226 Ask buyers before use.

Much more sewage sludge will be disposed of on land this year after the Jan 1 ban on dumping at sea.

Heat recovery unit costings

DAIRY producers can expect to wait six to eight years to see a return on investment in heat recovery units for heating milking parlour circulation water.

Thats the conclusion of a Farm Energy Centre and Milk Development Council study.

FECs Tim Pratt explains that the study compared savings possible with two types of heat recovery units used on bulk tank compressors.

Although savings of £100-130 were possible using heat recovery units, the units cost £600-800, ma-king them a long-term investment. But where a plate cooler was installed to pre-cool milk, savings through heat recovery would be reduced. He considers a plate cooler a better investment than a heat recovery unit.

Greater savings could be made using an Economy Seven tariff to heat all circulation water and by improving tank insulation, according to Mr Pratt.

A producer heating 230 litres (50gal) for each wash could save £300 a year by investing in a second boiler to heat water for the afternoon milking on E7. The boiler would cost £600-800, producing a quicker return on investment than a heat recovery unit, he says.

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