Blend feeding or feeding a single diet has no impact on growth performance or carcase value

Blend-feeding, where two extreme diets are mixed together in varying ratios (allowing the diet to be changed weekly), or feeding the same diet through the grower-finisher period (single), are alternatives to phase-feeding where three or four diets are fed during the grower-finisher period. Blend feeding or feeding a single diet have been found to have no effect on overall growth performance compared to a three-phase feeding program (Edwards 2011; Moore et al. 2013). However, there is some concern that the lysine level in the single diet used in these studies was not sufficient and as a result the true effect of feeding the single diet was not realised (Edwards 2011). The lysine requirements of Australian grower-finisher pigs have recently been reported to be approximately 10% higher than that used in these studies (Moore et al. 2015). Therefore blend feeding and feeding a single diet throughout the grower and finisher phases were re-examined using the higher lysine requirements. The hypothesis tested was that blend feeding or feeding a single diet will reduce the cost of feeding pigs compared to the phase-feeding system by minimising the excess of nutrients in the diets without adversely affecting pig growth performance and carcase quality.

A completely randomised block design experiment was conducted using 147 female pigs (Large White × Landrace × Duroc; seven pigs/pen and seven replicate pens/treatment) to examine the effect of feeding strategies on performance during the grower-finisher phases. Pigs of a similar age were blocked and randomly allocated to the following feeding strategies on the basis of initial liveweight (LW): Phase-feeding: diets changed when the average LW of pigs in the pen reached 30 kg (14.5 MJ digestible energy (DE)/kg and 0.84 g standardised ileal digestible lysine (SID Lys)/MJ DE), 50 kg (14.0 MJ DE/kg and 0.67 g SID Lys/MJ DE) or 80 kg (13.7 MJ DE/kg and 0.55 g SID Lys/MJ DE); Blend: diets changed weekly to meet the requirements of the average LW of pigs in the pen; and Single: the same diet fed throughout (formulated to meet the requirements of the pig at 60 kg LW; 13.9 MJ DE/kg and 0.65 g SID Lys/MJ DE). The experimental diets were fed for 10 weeks from 30.1 ± 0.33 to 97.3 ± 1.40 kg LW (mean ± SE). All data were analysed by analysis of variance (Genstat, 15th Edition; UK).

There was no effect (P > 0.05) of feeding strategy on growth performance (Table 1). The SID Lys intake required per kg LW gain was reduced for the Blend and Single feeding strategies compared to the Phase feeding strategy (P = 0.002). There was a trend for feed costs for pigs on the Blend and Single feeding strategies to be cheaper (4.36% and 5.05%, respectively) than those fed the Phase feeding program (P = 0.057). Single feeding or Blend feeding appears to reduce diet costs with minimal effect on growth performance and carcase value, thus confirming the results from Moore et al. (2012).

Table 1.  Growth performance, carcase quality and feed costs for female pigs using three different feeding strategies (n = 7)