# Comparison between phase feeding and diet blending on growth performance, carcass characteristics, and diet economics of finishing pigs raised in a commercial environment

## TL;DR

This study compares two feeding strategies for finishing pigs and finds that diet blending improves feed efficiency without affecting growth or carcass traits.

## Contribution

The study empirically compares phase feeding and diet blending in commercial pig production, revealing diet blending's impact on feed efficiency and cost.

## Key findings

- Diet blending reduced average daily feed intake and improved gain to feed ratio without affecting growth performance.
- Diet blending lowered feed cost per kilogram of gain, especially under high ingredient prices.
- Phase feeding and diet blending produced similar carcass characteristics and income over feed cost.

## Abstract

A total of 2160 pigs (initially 24.8 ± 0.97 kg) and 962 pigs (initially 26.5 ± 0.37 kg) were used in 2 experiments to compare diet blending with phase feeding on growth performance and profitability. Pigs were housed in mixed-gender pens with 20 and 26 pens per treatment in Exp. 1 and 2, respectively. Pens were assigned to treatment in a randomized complete block design and blocked by initial body weight. In Exp. 1, pens were assigned to treatments arranged in a 2 × 2 factorial comparing feeding strategy (phase feeding vs. diet blending) and standardized ileal digestible (SID) Lys (90 or 100% of requirement estimates). Phase-fed pigs were fed diets in 5 phases. For diet blending, low and high SID Lys diets were blended daily to achieve 90 or 100% of SID Lys requirements. Overall average daily gain (ADG) was not influenced by feeding strategy, but diet blending decreased (P = 0.002) average daily feed intake (ADFI) and increased (P < 0.001) gain to feed ratio (G:F). Hot carcass weight (HCW), fat depth, and loin depth were not affected; however, diet blending tended to reduce (P = 0.074) carcass yield and increased (P = 0.094) percentage lean. There was a tendency for greater (P = 0.066) income over feed cost (IOFC) with phase feeding under low ingredient prices, but diet blending had lower (P = 0.049) feed cost/kg gain under high prices. Lysine level did not affect overall growth performance, but pigs fed the 90% SID Lys diets had lower (P < 0.001) feed cost. In Exp. 2, two feeding strategies were compared. Phase-fed pigs were provided with diets in 3 phases until 114 kg with a common diet thereafter. Pigs fed the diet blending strategy used 2 of 3 diets mixed daily to follow the requirement estimate curve until 114 kg, then fed a common diet from 114 kg to market. Overall ADG was not influenced by feeding strategy, but diet blending decreased (P = 0.017) overall ADFI. Diet blending increased G:F (P = 0.019) from 26 to 114 kg, but not overall. In the experimental period, IOFC was unaffected by treatment, though feed cost per pig tended to be reduced (P ≤ 0.096) with blended diets. In conclusion, phase feeding and diet blending supported similar growth and carcass traits. Although IOFC was generally unaffected, diet blending reduced feed usage and feed cost/kg gain compared to phase feeding.

Diet blending resulted in improved feed efficiency but similar income over feed cost compared to phase fed finishing pigs.