EFFECTS OF COMBINATIONS OF WHEAT, CORN OR HULLESS BARLEY WITH HULLED BARLEY SUPPLEMENTED WITH SOYBEAN-MEAL OR CANOLA-MEAL ON GROWTH-RATE, EFFICIENCY OF FEED-UTILIZATION AND CARCASS QUALITY OF MARKET PIGS

In two factorial experiments involving 200 barrow pigs, 23-100 kg, three types of wheat, hulless barley and yellow corn replaced 0, 25, 50, 75 and 100% of the regular barley in the grain mixture. Diets were supplemented with soybean meal (SBM) or canola meal (CM):SBM 3:1 and in Experiment 3, two levels of lysine were compared in grower (0.8% and 0.9%) and finisher (0.7% and 0.8%) diets fed to 48 gilts and 48 barrows. The pigs were penned in groups of four and fed in individual feeding stalls. Replacing barley with high-energy grain had little effect on daily gain or feed intake in the grower period (23-57 kg pigs). Daily gains averaged 700 g. Efficiency of feed utilization was not improved as hard wheat replaced barley, but was improved as com, hulless barley or HY-320 wheat replaced barley. With pigs 57-100 kg, replacing barley improved daily gain and efficiency of feed utilization without affecting feed intake. The grower pigs fed 0.9% lysine had improved feed efficiency only when fed all-wheat diets. Finisher pigs showed no response to increased lysine. Replacing 100% of the barley improved dressing percentage from 76.7 to 78.3 but increased backfat from 22.3 to 26.3 mm, resulting in reduced lean yield and sale value which offset the benefit of increased carcass weight. The net advantage of using high-energy grains therefore related to reduction in days-to-market by 6-9 days, in 4-10% less feed required and to feed costs, which are specific to time and location.