Doubts cast over phase-feeding

PHASE-FEEDING pigs fails to improve any of the main production measures or cut feed costs despite matching pig diets with nutrient needs, according to the latest MLC research funded by BPEX and DEFRA.

In trials at the MLC’s Stotfold research unit, pigs were fed either a phase diet – adjusted daily according to liveweight – or a single diet from 35kg to 105kg liveweight, says MLC pig scientist Jayne Thompson.

“Phase feeding means a diet’s nutrient content is more carefully matched to pigs needs as they change over the growth period. In theory this means nutrients are used more efficiently and can result in reduced nutrient wastage and should mean growth potential is better exploited.”

Under or over-supplying nutrients, which can happen when pigs are fed the same diet at all stages of growth, can result in reduced growth efficiency and nutrient waste, says Dr Thompson. But this was not evident from the 1040-pig trial.

“In the trial, phase-fed pigs were given a diet blended using one diet formulated to meet the exact requirements of a 30kg pig and one formulated to meet the exact requirements of a 110kg pig diet. The inclusion rate of each was changed daily according to liveweight. But pigs on the single diet were fed a 70kg pig diet throughout the trial.” Both groups were fed ad-lib liquid diets.

“Pigs were weighed every two weeks and the phase diet was adjusted to meet target nutrient requirements according to their growth curve.”

With phase feeding, pigs consumed more of a higher specification diet early in their life and more of a lower specification diet later. But there were no differences in overall intake in the two extreme rations between phase and single-fed pigs.

“At Stotfold, pigs fed the single diet throughout had higher growth rates, gaining 886g a day compared with 860g a day for phase-fed pigs. The same trend was demonstrated over both stages of the trial, the grower stage and the finisher stage.” Feed conversion rates were the same for phase-fed and single diet-fed pigs. Both groups required 2.36kg of feed to gain 1kg of liveweight.

Health status was also similar for both groups with both showing almost no salmonella and stomach ulceration levels similar in both groups, reports Dr Thompson. “Overall, phase feeding failed to deliver any benefits in terms of performance or cost compared with feeding the single diet.”

LIVE T P4 FEEDING TRIALS

True phase feeding no benefit

Fermented feed more expensive

Improved meat quality with fermented cereal