Use of winter hybrid Rye in diets for organic growing-finshing pigs

Abstract

This study evaluated the effects of replacing 50% of corn with hybrid rye in growing-finishing pig diets on pig performance, carcass characteristics, and phosphorus concentrations in fecal and manure samples. A total of 500 pigs (initial body weight = 18.9 ± 2.94 kg) were assigned to either a Control or Rye treatment (50 pigs/pen; 5 pens/treatment) based on sex and body weight. Control pigs received a corn-soybean meal diet, while Rye pigs were fed a diet where hybrid rye replaced 50% of the corn. Pigs were housed in a hoop barn, with wheat straw bedding provided to Control pigs and rye straw for Rye pigs. Pig performance, including body weight (BW), average daily gain (ADG), average daily feed intake (ADFI), and feed efficiency (G:F) were recorded every 28 days. At the end of the trial, carcass traits such as final BW, hot carcass weight (HCW), backfat thickness (BF), and loin eye area (LEA) were measured. Feed samples from each dietary phase were analyzed for nutrient composition, including phosphorus and phytic acid concentrations. Fecal samples from 80 pigs (40 Rye and 40 Control) were collected and analyzed for phosphorus and phytic acid concentration. Manure and bedding samples were also collected before, at the start and end of the trial and during manure clean-out to assess composition. There were no differences in BW, ADG, ADFI, or G:F between Control and Rye fed pigs (P > 0.05). However, carcass yield and LEA were lower in Rye-fed pigs (P < 0.05). Mortality was lower in Rye-fed pigs (P < 0.05), while morbidity was not different between treatments (P > 0.05). Phosphorus concentrations in Rye diets were higher across most phases (P < 0.05), but there were no differences in phosphorus or phytic acid concentrations in the fecal samples between treatments. There were no differences between treatments for most manure traits collected during and after the trial and at manure clean out (P > 0.05). In conclusion, replacing 50% of corn with hybrid rye in growing-finishing pig diets did not affect growth performance but resulted in reduced some carcass traits, including carcass yield, back fat, and loin eye area.