Three experiments, using 344 pigs, were conducted to evaluate the influence of beta-glucan on growth performance, neutrophil and macrophage function, haptoglobin production, and resistance to Streptococcus suis challenge in weanling pigs. In Exp. 1, 144 pigs were used to evaluate the influence of .1% dietary beta-glucan in a soybean meal- or milk protein-based diet on growth performance and neutrophil function. Pigs fed beta-glucan from d 7 to 14 after weaning had lower ADFI (P < .01) and, although not significant, ADG was lower for pigs fed beta-glucan than for pigs fed control diets. However, no differences were observed in growth performance or neutrophil function for pigs fed control or diets containing beta-glucan from d 7 to 35 after weaning. Experiment 2 was a 28-d growth assay in which pigs were fed a diet with or without .1% beta-glucan, containing 7.5% spray-dried plasma protein and 25% dried whey from d 0 to 14 after weaning. Pigs then were fed corn-soybean mealbased diets containing 2.5% spray-dried blood meal and 10% dried whey. No differences in growth performance were observed. Experiment 3 was a 35-d assay to evaluate growth performance, neutrophil and macrophage function, and plasma haptoglobin concentration. Pigs were challenged on d 28 postweaning with intravenous S. suis. In Exp. 3, pigs were fed diets without or with .025 or .05% beta-glucan. Dietary beta-glucan did not influence neutrophil or macrophage function. However, pigs fed diets containing .025% beta-glucan had increased (P < .05) ADG and ADFI and were heavier (P < .05) on d 28 after weaning than pigs fed the control diet. No differences in feed efficiency (G/F) were detected between treatments. Pigs fed beta-glucan had decreased (P < .10) plasma haptoglobin on d 14, 21, and 28 after weaning. However, Fisher's Exact test revealed that more (P < .04) pigs fed a diet containing .025% beta-glucan died by d 12 after challenge with S. suis. In conclusion, these data suggest the existence of a complex interaction involving growth performance and resistance to S. suis in pigs fed .025% beta-glucan.

We conducted four experiments to examine the effects of adding zinc oxide (ZnO) and(or) copper sulfate (CuSO4) to diets for weanling pigs. In Exp. 1 and 2, weanling pigs (initially 5.3 kg and 19 +/- 2 d of age) were fed diets containing 250 ppm of added Cu (CuSO4) and either 110 or 3,110 ppm of added. Zn (ZnO). No differences (P > .10) were observed in either experiment for ADG, ADFI, or feed efficiency (G:F). In Exp. 3,240 pigs (initially 4.45 kg and 15 +/- 2 d of age) were used to determine the interactive effects of added dietary ZnO and(or) CuSO4. Dietary treatments were in a 2 x 2 factorial arrangement; Zn (165 or 3,000 ppm) and Cu (16.5 or 250 ppm) were the main effects. Pigs were fed a high nutrient dense diet from d 0 to 14 after weaning and a less complex diet from d 14 to 28 after weaning, both containing the same mineral fortifications. From d 0 to 14, pigs fed 3,000 ppm Zn, with or without 250 ppm Cu, had improved ADG (P < .01) compared with pigs fed the control (16.5 ppm Cu and 165 ppm Zn) or diets with only added Cu. From d 14 to 28, pigs fed the diet containing 3,000 ppm added Zn, without 250 ppm Cu, had greater ADG than pigs fed the other diets (Zn x Cu interaction, P < .01). In Exp. 4, 264 pigs (initially 4.17 kg and 12 +/- 3 d of age) were fed a high nutrient dense diet supplemented with 3,000 ppm of Zn (ZnO) from d 0 to 14 after weaning. On d 14, pigs were switched to the diets containing experimental mineral levels identical to those of Exp. 3. From d 14 to 28 after weaning, added Zn improved ADG but not when the diet contained 250 ppm Cu (Zn x Cu interaction, P < .05). Feeding 3,000 ppm of Zn from ZnO is a viable means of improving nursery pig performance, but additive responses to growth-promotant levels of CuSO4 (250 ppm Cu) were not observed.

Eighty-four crossbred gilts were used to evaluate the effects of dietary choice white grease (CWG) or poultry fat (PF) on growth performance, carcass characteristics, and quality characteristics of longissimus muscle (LM), belly, and bacon of growing-finishing pigs. Pigs (initially 60 kg) were fed a control diet with no added fat or diets containing 2, 4, or 6% CWG or PF. Diets were fed from 60 to 110 kg and contained 2.26 g lysine/Mcal ME. Data were analyzed as a 2 x 3 factorial plus a control with main effects of fat source (CWG and PF) and fat level (2, 4, and 6%). Pigs fed the control diet, 2% fat, and 4% fat had greater (P < 0.05) ADFI than pigs fed 6% fat. Pigs fed 6% fat had greater (P < 0.05) gain/feed (G/F) than pigs fed the control diet or other fat levels. Subcutaneous fat over the longissimus muscle from pigs fed CWG had more (P < 0.05) moisture than that from pigs fed PF. Feeding dietary fat (regardless of source or level) reduced (P < 0.05) the amount of saturated fats present in the LM. Similarly, 4 or 6% fat decreased (P < 0.05) the amount of saturated fats and increased unsaturated fats present in the bacon. No differences (P > 0.05) were observed for ADG, dressing percentage, leaf fat weight, LM pH, backfat depth, LM area, percentage lean, LM visual evaluation, LM waterholding capacity, Warner-Bratzler shear and sensory evaluation of the LM and bacon, fat color and firmness measurements, or bacon processing characteristics. Adding dietary fat improved G/F and altered the fatty acid profiles of the LM and bacon, but differences in growth rate, carcass characteristics, and quality and sensory characteristics of the LM and bacon were minimal. Dietary additions of up to 6% CWG or PF can be made with little effect on quality of pork LM, belly, or bacon.

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A regional experiment was conducted at 8 experiment stations, with a total of 320 sows initially, to evaluate the efficacy of adding 13.35% ground wheat straw to a corn-soybean meal gestation diet for 3 successive gestation-lactation (reproductive) cycles compared with sows fed a control diet without straw. A total of 708 litters were farrowed over 3 reproductive cycles. The basal gestation diet intake averaged 1.95 kg daily for both treatments, plus 0.30 kg of straw daily for sows fed the diet containing ground wheat straw (total intake of 2.25 kg/d). During lactation, all sows on both gestation treatments were fed ad libitum the standard lactation diet used at each station. Response criteria were sow farrowing and rebreeding percentages, culling factors and culling rate, weaning-to-estrus interval, sow BW and backfat measurements at several time points, and litter size and total litter weight at birth and weaning. Averaged over 3 reproductive cycles, sows fed the diet containing wheat straw farrowed and weaned 0.51 more pigs per litter (P