| Abstrakt: |
Three 5-wk nursery trials using 264 crossbred weanling pigs (6.7 kg initial weight) were conducted to determine the effects of adding 5% soybean oil to starter diets on nursery air quality and performance of weanling pigs. Four dietary treatments were fed in two nurseries of similar design: 1) basal diet (corn-soybean meal), 2) basal diet + 15.6% soybean hulls, 3) basal diet + 5% soybean oil and 4) basal diet + soybean hulls and soybean oil. Diets 1 and 2 without oil were fed in one nursery and diets 3 and 4 with oil were fed in the other nursery during trial 1 and in the alternate nursery with each subsequent trial. Diet 4 was made isocaloric (metabolizable energy) with diet 1 so that the effects of reduced dustiness could be assessed independently of increased caloric density. Ammonia (1.1 to 2.8 ppm) and carbon dioxide (900 to 1,900 ppm) concentrations, which were well within normally accepted levels, were not consistently influenced by the addition of soybean oil to the diet. Settled dust was reduced by 45 to 47% when 5% soybean oil was added to the diet (P<.01). Total aerosol bacterial colony counts increased over time and were 27% lower for pigs fed diets with added soybean oil (P<.01). The addition of soybean oil and soybean hulls to the basal diet had no overall effect on average daily gain, but added soybean oil tended to reduce average daily feed intake (4.3%; P<.13) and improved feed per gain (F/G) by 4.1% (P<.05). Added soybean hulls increased average daily feed intake (ADFI) by 5.8% (P<.05) and F/G by 3.6% (P<.05). However, the effects of soybean hulls (increased ADFI and F/G) were less when soybean oil was added to the diet. A comparison of pigs fed isocaloric diets (diet 1 vs diet 4) showed no differences in performance. The addition of 5% soybean oil to a starter diet was effective in reducing settled dust, bacterial colony counts and improving feed efficiency, but when isocaloric diets were fed in the nurseries, with and without soybean oil, pig performance was not different. |
