Better Pork - April 2007

Eye On Europe

Human ‘sniffers’ help set the limits for hog farm odour in Denmark

Their findings are being converted into an odour table which is being used to define the number of “standard odour units” permitted near towns or villages – all part of stiffer controls on livestock odour emissions
 
by NORMAN DUNN

Stricter controls for hog farm odour see professional “sniffer” panels being hired in Denmark to decide when neighbours are justified in calling foul.

Control of general odours from livestock housing is now the most important factor restricting further expansion of Danish hog production, according to Orla Grøn Pedersen, director of that country’s national production organisation, Danish Pig Production.
Test panels of human “sniffers” have defined an odour table after testing air emissions from more than 200 different types of pig housing in Denmark last summer. The results have been converted into European “standard odour units.”

Now the Danes have decided that a maximum seven odour units are permissible when these reach the village nearest to a hog farm and only one single odour unit is allowed to drift into the nearest town or city.

Introduced in January of this year, the livestock odour limits only apply to new livestock barns for the moment. The “sniffer” panels have already decided on average levels of smell from typical types of production barns. These are used as standards when a farmer applies for planning permission near a village or town. The wind direction and local climate also play a role. But should the odour lead to complaints after the barn is in operation, then smell levels will be reassessed and the farmer could end up having to renew outlet air filters at the least, or close down his new barn in the worst case.

Arne Grønkjær Hansen is one of the experts from the Agricultural Advisory Centre now helping farmers cope with the demands of the new odour table. His centre has produced guidelines for farmers to help them reduce potential odour through design changes in the barns. These include:
• Fitting a higher exhaust air stack;
• Decreasing the area of slatted floor in the building;
• Reducing ventilation airflow in general, and by extra cooling of intake air in summer.

… And a Danish biofilter system reduces emissions

Ammonia emission levels can also be dealt with simply through reducing protein in the feed and rather more expensively by an emission filter system, say Danish advisers. Equipment manufacturer SKOV has been developing the filter technique, which also takes out other smells.

The latest offering, presented at the Agromek exhibition this winter, features self-contained “Farm AirClean BIO” modules, which can be fitted in the roof space of hog houses. The compact double filter system involved is not cheap, costing between $110,000 and $140,000 Cdn in Denmark for a unit capable of cleaning air emissions from a 2,000-place hog feeding barn. But it is claimed to be extremely efficient with 95 per cent of dust and “almost all” odour taken out and the ammonia content of outgoing air substantially reduced.

Recirculating water is sprayed continuously on the filters and a natural colonization of micro-organisms forms a biofilter. The SKOV system comes with an automatic cleaning system which hoses dust out of the filters once per day. Danish Pig Production calculates that running the biofilter could cost from $3 to $3.60 Cdn per hog.

Chemical filtration of emission air, as offered by ScanAirclean, claims a drop of at least 90 per cent in ammonia emissions and “considerable reduction” of pig smells. The system features a central filter plant where the air is sprayed with an aqueous acid solution which chemically breaks down ammonia as well as trapping dust and odour-causing compounds. The calculated cost is $2.90 to $3.30 Cdn per feeding hog.

A system of acidification of the liquid manure takes out nearly all the ammonia from hog barn emission air, though unfortunately leaving all the other smells. It changes pH from an average 9.1 to 5.5 and effectively stops 70 to 80 per cent of all ammonia evaporation. What’s more, the acidification system is comparatively cheap. The 80 per cent pure sulphuric acid required costs the equivalent of around $0.95 Cdn to treat a tonne of slurry.

Ammonia control has already come a long way on Danish farms. In the last 20 years, emissions have been reduced by 45 per cent and the Copenhagen government wants further cuts of 25 per cent by 2009.

At Agromek this January, Pedersen concluded: “In this country, we slaughtered 25.7 million pigs in 2005 and we can perhaps expect this to rise by another 3 million in 10 years. But everything will depend on the control of emissions and smells if Denmark is to continue as world leader in pig meat export.”

Switzerland gets ready for free farrowing

As of the end of June this year, farrowing crates will be banned in all hog production farms in Switzerland. The good news for the country’s 3,000 or so sow herd owners is that 10 years of trials have shown that piglet mortality is not really any higher with so-called free farrowing.

One such trial held on commercial farms by the Swiss Research Institute for Agriculture and Farm Machinery (FAT, Tänikon) looked at piglet mortality in a total of 18,824 farrowings in pens with no crate and compared the results with more than 44,000 farrowings where the sows were confined in a standard-sized crate.

Results were recorded over two years and the outcome was that mortality to weaning at three to four weeks averaged 12.1 per cent for free farrowing – exactly the same figure reached in confined farrowing pens.

As expected, the percentage of piglets killed by the sow laying on them was higher in the free farrowing pens – at 5.5 per cent compared with 4.4 per cent. On the other hand, only 6.6 per cent of all piglets in the free farrowing pens died from “other causes,” compared with 7.6 per cent for the confined sow systems. This backs up findings from recent Danish research indicating that slower, weaker, perhaps diseased, piglets were more likely to be killed by the sow laying on them in a free farrowing environment, but would probably die anyway (although less suddenly) where they are protected from the sow.

The Swiss work showed that there was no difference made in the free farrowing mortality rate by the presence of emergency confinement gates for the sow or shelter railings for the piglets around the pen walls. The percentage of piglets killed by the sow laying on them in free farrowing systems did rise, however, in direct line with increasing size of litter. The Swiss researchers found that this percentage increased rapidly where more than 12 were born alive per litter.

Oregano – a handy replacement for growth-promoting antibiotics

A new crop is being tested in Dutch fields which provides a natural performance boost when included in the rations of young hogs. Oregano is the name of the plant involved. This herb already grows well in warmer countries, of course, but now Dutch and German research indicates that it provides a very efficient replacement for growth-promoting antibiotics in hog – and other livestock – feeds.

The problem is that the crop’s important ingredient in this case, the antimicrobial oil carvacrol, varies wildly in content and quality according to where the oregano is grown. This is why northern European farmers want to grow their own so that a standard quality of carvacrol can be produced for use in hog feed.

The work is all the more important because the use of normal antibiotics as growth promoters in feed was banned completely in Europe from January 2006.

The oregano-based substitute is certainly well worth including in young hog rations according to recent results from Thuringia Agricultural Institute in Germany. These indicated that the natural oregano component boosted weaner feed intake by 2.7 per cent from day 28 to 70.    

Daily liveweight gain over the same period was increased by an average 16 grams to 420 grams and feed conversion ratio was about the same for the groups receiving carvacrol and for those on a standard diet. The additive was tested in a conventional starter ration, being added at the rate of one kilogram per tonne of feed for the first two weeks and thereafter at 500 grams per tonne.

New trough with built-in nipples keeps piglets happy

A new trough from Denmark equipment producer Biofiber-Damino is especially designed to encourage very young piglets to start eating their first dry creep or oral iron ration.

Based on intensive study of how young piglets play, the plastic trough has an embossed diamond pattern along the bottom, which also features plastic “teats.” “These are shaped just like the sow teats the piglets are already well acquainted with,” explains Damino sales manager Kell Jensen. “We have found that they attract the young hogs to stick their noses into the trough right away. They try to suckle the teats and then the uptake of dry feed starts immediately.”

Jensen adds that the textured trough bottom works in the same way. “It has been shown in trials that it is natural behaviour for young animals to use their snouts to probe and play with such textured material, just as they would when learning to root out in the open. Once again, we have found that this helps to encourage rapid acceptance of first dry feed.”

The new trough comes with a metal bracket for attachment to the farrowing pen creep area wall and the trough can be angled to make access easier for very young piglets.

Swiss feeders turn to acid

Hog farmers in Switzerland are also searching for antibiotic growth promoter alternatives. The country’s Hendschicken Research Centre, run by animal nutrition and feed production company UFA, is trying benzoic acid in feed as another way of controlling pathogens in hog intestines and so increasing performance. Bugs such as E. coli are probably reduced through lowering intestinal pH with the acid additive, reckon the Swiss researchers.

Certainly, first results indicate a plus for this approach, with daily liveweight gain in feeding hogs increased by 2.5 per cent and almost the same increase apparent in feed conversion efficiency. The trial featured 150 hogs of the same breeding and on standard rations. Half received benzoic acid in their ration at 7.5 kilograms per tonne.