Performance of growing-finishing pigs fed barley-based diets containing graded levels of number 1 wheat screenings

Abstract

This experiment was conducted to determine the effect of graded levels of number 1 wheat screenings on performance, nutrient digestibility and carcass traits when fed to growing-finishing pigs. Forty crossbred pigs (Camborough 15 Line female × Canabred sire) weighing an average of 19.7 ± 2.8 kg were assigned to one of five dietary treatments in a 5 × 2 factorial design experiment. The main effects tested included level of wheat screenings and sex of pig (barrows and gilts). The levels of inclusion were 0, 18, 36, 54 and 72% in the grower diet and 0, 20.5, 41, 61.5 and 82% in the finisher diet. Screenings were added largely at the expense of barley. A botanical analysis was preformed and it indicated that the screenings contained approximately 88.5% whole or cracked wheat with the most prevalent weed seeds being wild buckwheat (6.7%), canola seed (2.8%) and cleavers (0.96%). There was a linear (P = 0.001) increase in the digestibility of dry matter, crude protein and gross energy with increased incorporation of wheat screenings in the diet. Over the entire experimental period (19.7–105.1 kg), there was no change in growth rate due to feeding wheat screenings, but feed intake declined in a linear (P = 0.044) fashion while feed conversion improved linearly (P = 0.014) as the inclusion level of screenings increased. There were no sex effects on pig performance. Dietary inclusion of wheat screenings had no significant effects on any carcass traits including dressing percent, carcass value index, lean yield, loin fat or loin lean. The carcass value index for gilts was higher than that of barrows (P = 0.038). The overall results of this experiment indicate that number 1 wheat screenings can be successfully uti lized as an energy source for use in growing-finishing diets and can be fed at levels as high as 72% for growing pigs and 82% for finishing pigs with no negative effects on pig performance or carcass quality. However, should the level of weed seeds increase or the type of weed seeds contaminating the screenings change appreciably from those reported here, then it may be necessary to reduce the incorporation level of screenings in the diet. Key words: Pigs, wheat screenings, performance, digestibility, carcass