Phase-feeding strategies based on lysine specifications for grow-finish pigs1

Abstract

Four experiments were conducted using 1,100 to 1,188 pigs each (PIC 359 × 1,050) from ~27 to 127 kg BW to evaluate phase-feeding strategies based on Lys specifications and number of dietary phases for grow-finish pigs. Different phase-feeding strategies were used in each experiment with treatments consisting of a combination of 3 Lys specifications at 96%, 98%, or 100% of estimated requirement for growth rate and 4 phase-feeding strategies with 1, 2, 3, or 4 dietary phases. A single-phase-feeding strategy reduced (P < 0.05) overall growth performance, live BW, and HCW whether Lys specifications were at 98% or 100% of estimated requirements compared with multi-phase-feeding strategies. Lysine specifications at 96% of estimated requirements in a 4-phase-feeding strategy reduced (P < 0.05) overall growth performance compared with feeding strategies with Lys at 100% of estimated requirements, unless Lys specifications were increased to 100% of estimated requirements in the late finishing phase. Lysine specifications at 98% or 100% of estimated requirements in a 2-, 3- or 4-phase feeding strategy led to similar (P < 0.05) overall growth rate, live BW, and HCW of grow-finish pigs. Pigs fed 1, 2, or 3-phase feeding strategies or feeding strategies with Lys below the requirements in early grow finish had improved growth performance driven by improved feed efficiency in the period following low Lys levels, indicating the occurrence of compensatory growth. For carcass characteristics, there was no evidence (P > 0.10) for differences in carcass yield, back fat, loin depth, or lean percentage across feeding strategies in any of the experiments. In conclusion, phase-feeding strategies provide performance advantages over feeding a single dietary phase throughout the grow-finish period. Simplification of feeding strategies from 4 to 3 or 2 dietary phases with Lys specifications at 98% to 100% of estimated requirements for growth rate does not compromise overall growth performance and carcass characteristics of grow-finish pigs from 27 to 127 kg BW. Although, using feeding programs with fewer dietary phases and Lys set slightly below the requirements can compromise growth performance if initial BW and feed intake in the grow-finish period are lower than expected.

Increasing Dietary Lysine Impacts Differently Growth Performance of Growing Pigs Sorted by Body Weight

“…However, as the diets were only tested on low BW pigs, doubts arise whether some response would have been observed on the heavier pigs. Although studies involving different phase-feeding strategies might give an indication if growth of small pigs is impaired or improved by different strategies, these effects have not been reported in those works [ 7 , 8 ].…”

“…Pigs with a low body weight (BW) continue to be a major concern in all-in all-out swine production systems, as they have been associated with a longer time to reach marketing [ 1 , 2 , 3 ], a greater mortality rate [ 2 , 3 , 4 ], and the resulting inefficiency of phase feeding strategies [ 5 ]. The latter, being a widespread feeding system, aims to mimic the reduction in the optimal concentration of lysine in the diet required for growth with increasing BW [ 6 , 7 , 8 ]. Practical application of phase feeding programs consists in delivering a specific amount of each feed to the farm, aiming to fulfill the requirements of the average pig.…”

“…However, as light pigs are known to have a lower feed intake than their heavier mates [ 9 , 10 , 11 , 12 ], they might eat a lower amount of the first feeds, and therefore less lysine during the early stages both in the nursery and growing facilities. Even though phase feeding focuses on feeding pigs more precisely [ 7 ], the inherent BW variability of swine production systems [ 13 ] might represent that the requirements of the lightest pigs might not be fulfilled when applying this strategies [ 14 ].…”

A review of compensatory growth following lysine restriction in grow-finish pigs1

“…Recent studies with grow-finish pigs reared in commercial research conditions validate the database analysis and indicate that compensatory growth can occur in the field ( Menegat et al, 2019 ). The same criteria and methods used to develop the database were applied to commercial studies.…”

“…The distribution of the field comparisons into quadrants depicts a similar pattern to the database comparisons, indicating the occurrence of complete, incomplete, and no compensatory growth. The growth patterns and the occurrence of compensatory growth throughout the grow-finish period are further illustrated in Menegat et al (2019) .…”