21 May 1999

Dont look for one alternative

NO single alternative to AGPs exists – the industry will have to turn to a combination of factors to replace them.

"Some of the more potent organic acids – such as formic acid – may give good results but in general treat these products with caution because of handling difficulties and their corrosive effect on equipment and slats," said scientist Pinder Gill.

Dr Gill said pre-fermentation of feed was the most promising way to feed pigs to promote gut health

"In an optimal pre-fermentation feeding system I dont see why some, if not all of the benefits of AGPs could be achieved."

But more work was needed before producers could introduce fermentation technology with confidence.

Fermentation warning

Caroline Bevan of Banbury Agriculture also warned of the risks of poor fermentation.

"When everything is carried out correctly fermentable feeds work well, but on farm the process must be carried out carefully and hygienically."

Of the options available, she would rather choose enzymes or an organic acid. "We know their mode of action and have proven results for them.

"When the concern is enteric, organic acids – such as calcium formate – will help, while enzymes will help improve the digestibility of starch in the diet."

Pig consultant Vernon Fowler cautioned against using the weak organic acids.

"One claim for organic acids is that for the gut to be healthy it should be acidic. But weak acids when added to the gut act as buffers and raise the pH. Only strong organic acids such as lactic, formic, and citric seem to be beneficial."

However, formic acid could be dangerous when used in large quantities and he said he was not overly enthusiastic about the acidifying approach.

Although probiotics were widely marketed, they were not very effective unless natural gut flora were inhibited. "Im not a great fan of these."

Enzymes interesting

Enzymes could help reduce enteric diseases and were quite interesting, as were fermentable substrates which encouraged friendly gut bacteria, said Dr Fowler.

Pre-fermentation of diets was worth considering, but hygiene was a problem and there was a danger of multiplying up pathogens, he said.

His preferred option was to opt for a less intensive system of production, and to feed selected fermentable substrates – readily fermentable in the small intestine.

ALTERNATIVES TO AGPs

&#8226 Probiotics.

&#8226 Organic acids.

&#8226 Enzymes.

&#8226 Nutraceuticals.

&#8226 Zeolites.

&#8226 Fermentable substrates – prebiotics.

&#8226 Pre-fermentation of diets.

&#8226 Immunisation.

&#8226 Alternative production systems.

AGPs – lessen

shock

By Sue Rider

IMPROVE husbandry and hygiene before considering alternative AGPs, warn consultants.

"The industry cant remove AGPs overnight without first minimising the impact of doing so," cautioned pig scientist Pinder Gill. Swedish experience of a total ban was an increase in enteric disease, and in the level of antibiotics used.

"UK producers must make changes to husbandry first to avoid a similar aftershock. Examine the factors impinging on stock health and see how these could be improved to minimise the shock of removing AGPs," Dr Gill advised.

"It could be that we have to follow the Swedish example of weaning later, at four to six weeks so the piglet is better able to defend itself."

Another advocate of later weaning was pig consultant Vernon Fowler. Speaking at an event seminar, he said alternative systems of production would be important.

"If we had never had access to AGPs, we would have had better systems of husbandry. We must now rethink our management. Delay weaning, reduce stocking density, improve ventilation, isolate diseased stock, reformulate diets, and pay more attention to hygiene," he said.

"I would switch to a less intensive system with later weaning -and feed selected fermentable substrates – in response to a total ban. The expense would be nothing like what the disease would cost me if I didnt do it."

Suffolk based vet Jake Waddilove also advised focusing on management.

"Substituting one growth promoter for another might only be a short-term answer. For the long term, focus on management and installing control systems to avoid pathogenic build up," he said.

Key target areas would, therefore, be later weaning, all in/all out and segregation, hygiene, environment, feeding, vaccination and medication.

"All in/all out and segregation is a major tool in controlling disease – we must drive towards this target and do it properly."

Trials showed daily liveweight gain and feed intake decreases by half over a four year period – from an average of 800g dlwg to 400g, and from 420g intake to 220g on continuous production systems. All in/all out increased dlwg from 650g to 850g, he said.

set in panel please

AGP UPDATE

Avoparcin was lost last year, and the number of AGPs available for use will be reduced further this summer with tylosin, spiramycin, virginiamycin,

and zinc bacitracin banned from June 30; carbadox and olaquindox from August 31.

Only three AGPs will be authorised for use by European pig producers – avilamycin, flavomycin, and salinomycin. Change is driven by concerns over antibiotic resistance.

Sweden banned AGPs several years ago and Denmark taxes feed containing AGPs with a total ban likely.

COPING WITHOUT AGPs

&#8226 Improve hygiene and husbandry.

&#8226 All in/all out and segregation.

&#8226 Consider alternatives carefully.

&#8226 Controlled environment.

&#8226 Enhance feed quality.

&#8226 Vaccination and medication.

AGPupdate

Avoparcin was lost last year, and the number of AGPs available for use will be reduced further this summer with tylosin, spiramycin, virginiamycin,

and zinc bacitracin banned from June 30; carbadox and olaquindox from August 31.

Only three AGPs will be authorised for use by European pig producers – avilamycin, flavomycin, and salinomycin. Change is driven by concerns over antibiotic resistance.

Sweden banned AGPs several years ago and Denmark taxes feed containing AGPs with a total ban likely.

Do check pedigrees

ALTERNATIVES to AGPs give a more variable and inconsistent response claim researchers, and many lack sufficient scientific trial data to prove efficacy.

"There are several potential alternatives to AGPs, but most havent gone through the efficacy testing thats needed. They must be properly tested before the industry can be fully confident in their use," said Pinder Gill.

He also warned that alternatives gave a variable and inconsistent response compared with antibiotics and would not completely replace their effectiveness.

BOCM Pauls nutritionist Martin Owers added: "The biggest difficulty with alternatives is their variability and inconsistency."

The compounder has been looking at AGP alternatives for the last three years. Of the 37 it screened, only 14-15 were worth looking at and just two gave a consistent benefit over the control.

"Loss of AGPs will cost from 50p-£1/pig depending on the farm – we hope to claw at least half of that back through use of these alternatives."

Banbury agriculture nutritionist Caroline Bevan suggested making sure alternatives are quality controlled. "Have some means of tracking to ensure they are in the feed when they are supposed to be."

Aberdeen Universitys Sandra Edwards also advises checking alternatives were reputable. "In the past AGPs have had to demonstrate efficacy and safety – ask the same of other products."

Cost of removal

COST of production without AGPs is likely be about £1 a pig from 35kg onwards, but will vary from farm to farm according to health status and management.

The Danish industry, which imposed a voluntary ban on all AGPs in pigs more than 35kg, reckons it costs £1.06 a pig due to reduced growth and feed efficiency. In Sweden, where AGPs were banned some years ago, the cost is £2.31 a pig.

According to Sandra Edwards of Aberdeen University, farm experience suggests the cost of producing without AGPs could be 50p-£2 a pig depending on the bug profile on that farm.

"On the average farm theres a 5% loss in efficiency – this will seriously disadvantage European producers competing on a world market," said Dr Edwards.