5 February 1999

Questioning the need for AGPs

LIKE most other pig units, antibiotic growth promoters feature in most weaner and finisher rations at Easton Lodge despite a ban on four products last December and further product bans anticipated. But unit manager Jasper Renold is now questioning the need for them.

"I think we see them as necessary to safeguard performance, particularly in weaners. But if you were to ask me how much benefit they give, I couldnt tell you."

Its taken for granted that AGPs smooth the performance dip associated with weaning and boost growth rates in finishers. But Mr Renold admits that benefits from AGPs have not been quantified on-farm. "I think were continuing to use them because theyre seen as a relatively cheap form of insurance."

The units consulting vet Richard Potter says Easton Lodge is not alone. Many producers wont have changed anything following the ban. Instead, feed mills have taken the decision for them. "Although some products have been removed, mills will start using another AGP and simply inform customers of the switch," explains Mr Potter.

To determine the benefits of AGPs, two trials are now running at Easton Lodge. In the first, some weaner groups passing through the flat decks will have olanquidox at 100mg/kg of feed – used to improve growth and feed conversion – removed from diets. Health status and growth rates will be compared to those on treated diets.

However, as a precautionary measure, prescribed use of zinc oxide at 2500mg/kg of feed – used to prevent non-specific scours – will continue in weaner diets. This may be cut completely if removal of olanquidox does not significantly affect performance, says Mr Renold.

The second part of the trial is focusing on second stage grower pigs going from 40kg to 65kg liveweight. The effect of removing tylosin currently fed at 40mg/kg of feed is being monitored to give an indication of growth rate and feed efficiency in a house which hasnt been washed for three months.

It may be found that AGP use in both weaners and growers, as Mr Potter suggests, is reducing the effect of bugs affecting the gut which can be picked up from faeces. Where hygiene isnt a concern, theres likely to be a small economic benefit from ending their use. Typically, treating feed for weaners and growers costs no more than £3/t.

"I wouldnt be at all surprised if there was no dip in grower performance following AGP removal, given the right management and hygiene. However, my feeling is there will be a drop in performance for weaners," warns Mr Potter.

The trial isnt going to provide scientific results, warns Mr Renold. "It will hopefully give an indication of the benefits were getting from AGP use. I suppose really its that Im curious to see what will happen if a total ban is introduced.

"If we see a significant drop in pig performance then well move on and look at AGP alternatives such as acidifiers and enzymes."

AGPREMOVAL

&#8226 Benefits are unknown.

&#8226 Look at alternatives.

How much performance benefit do AGPs really give in pig production?

Warning about weaners

REMOVING AGPs from finishers rations is fine, but be wary of removing them from weaner feed.

Thats the conclusion of Herts producers Bill Barr, who removed AGPs from all feed after signing up to a new supply contract in August last year. Although finishers have not been affected, weaner performance has slipped, with signs of looseness in faeces. With no apparent cause for this, AGPs were soon back on the menu for weaners.

The new contract offers a 12p/kg deadweight increase in price, but conditions include removal of AGPs above 25kg liveweight and no teeth clipping or tail docking, explains Mr Barr who runs 160 sows at Dale End Farm, St Albans.

"Last summer I believed an industry ban on AGPs was likely; I wanted to know what would happen if AGPs were removed altogether. The best a feed company could say is Id lose seven to 10 days growth. My impression was that nobody actually knew," he explains.

Mr Barrs own gut feeling was he would lose two to three days growth through to finishing. Subsequently AGPs were removed from all diets.

"Almost immediately afterwards we began to see some looseness in weaner faeces, but nothing in finishers," he explains. Scrutiny for a possible cause revealed nothing. Weaners stay in the same group through to finishing; hygiene isnt a concern, and theres little chance of cross-contamination with the nearest pig unit four miles away.

But the units pig vet John Carr says faeces looseness may never be avoided completely. When feeding a single weaner ration there will be days when individual piglet growth and feed intake wont match, leading to a mild overload of the digestive system.

This can be exacerbated with erratic changes in weather conditions, particularly in winter and spring, explains Mr Carr. Introducing a feed additive, whether an AGP or an alternative may be necessary to counter digestive problems even on units with good hygiene and performance. &#42