Report no. 471
25.05.2000
3-phase feeding of finishers with differentiated phosphorus standard
Abstract
A test of 3-phase feeding compared to feeding with one diet
throughout the entire growth period (the unit mix for finishers
30-100 kg) has been carried out.
The test was carried out in three herds with pigs in the growth
interval 32 to 100 kg. Dry feeding was used ad libitum. The test
comprised 121 blocks (replicates) and a total of 4,845 produced
finishers.
The feed analyses showed 3-6% surplus content of crude protein in
herds A and B, and deviations in mineral content in all herds in
the interval –7 to +43%.
The results showed that for all herds in general there was no
significant difference in the production value between the control
group and the phase feeding group when average prices of 5 years
were used. However, phase feeding resulted in a significant
decrease in the lean meat percentage of 0.4 percentage units.
In herd A, phase feeding had a significantly negative effect (4%)
and in herd B a significantly positive effect (4%) on the
production value, whereas in herd C there was no evident effect of
phase feeding on the production value. It is likely that the higher
production value of phase feeding in herd B may partly be due to a
deficiency of calcium and phosphorus in the control group, and
partly to the concentration of energy being graduated – as opposed
to herds A and C – into the lowest level in the final diet. This
may improve the lean meat percentage, especially for the castrates
when fed ad libitum.
In this test, 3-phase feeding resulted in a reduction of 4.5% in
discharge of nitrogen, and of 2.5% in discharge of phosphorus per
produced finisher compared to the unit mix (control).
It is problematic to attempt phase feeding when the aim is to
reduce protein and phosphorus by 4-5% if or rather when the mixing
uncertainty is 5-6% or above. This creates a great risk of a
deficiency of nutrients of the pigs.
On the basis of this test, phase feeding for finishers is only
recommended when it can be conducted without any or only few extra
investments as a consequence eg. at multisite and certain liquid
feeding systems. Furthermore, thorough analyses of the ingredients
and a good mixing certainty are perquisites for phase
feeding.
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