A. L. Sutton

DIETARY PROTEIN AFFECTS NITROGEN EXCRETION AND AMMONIA EMISSION FROM SLURRY OF GROWING-FINISHING PIGS

The effects of dietary protein on nitrogen excretion and ammonia emission from slurry of growing-finishing pigs were studied both in vitro and in a pig house. The three diets had similar contents of NE, minerals, vitamins and ileal digestible lysine, methionine + cystine, threonine and tryptophan, but differed in CP content (16.5, 14.5 and 12.5%). In the balance experiment, 18 castrated males of about 55 kg body weight were allotted to the three diets. The experiment lasted 9 weeks, which were divided into three 3-week periods. In each period, urine and faeces were collected separately for 7 days in metabolism cages and mixed as slurry. A sample of this slurry was placed in a laboratory system to measure ammonia emission for 7 days. In the barn experiment, 216 pigs were housed in three compartments and fed the experimental diets. Ammonia emission was measured directly from the compartments for 7 days during each of the 3-week periods. There was no effect of dietary CP level on faecal nitrogen excretion. Urinary nitrogen excretion and slurry pH decreased when dietary CP decreased. Both balance and barn experiments showed similar effects of dietary CP on ammonia emission from slurry. Ammonia emission was reduced by 10-12.5% for each percent decrease in dietary CP. It is concluded that lowering dietary CP and supplementing essential amino acids while maintaining normal growth rate reduces urinary nitrogen and ammonia emission from the slurry of growing-finishing pigs.

Controlling Salmonella infection in weanling pigs through water delivery of direct-fed microbials or organic acids. Part I: Effects on growth performance, microbial populations, and immune status1

Pigs (n = 88) weaned at 19 ± 2 d of age were used in a 14-d study to evaluate the effects of water-delivered direct-fed microbials (DFM) or organic acids on growth, immune status, Salmonella infection and shedding, and intestinal microbial populations after intranasal inoculation of Salmonella Typhimurium (10(10) cfu/pig). Pigs were challenged with Salmonella 6 d after commencement of water treatments. Treatments were 1) control diet; 2) control diet + DFM (Enterococcus faecium, Bacillus subtilis, and Bacillus licheniformis) in drinking water at 10(9) cfu/L for each strain of bacteria; 3) control diet + an organic acid-based blend (predominantly propionic, acetic, and benzoic acid) in drinking water at 2.58 mL/L; and 4) control diet + 55 mg/kg of carbadox. Serum samples were taken on d 6, 8, 10, and 14 for determination of tumor necrosis factor α (TNFα) concentrations. Fecal samples were taken on d 0, 5, 7, and 11 for determination of Salmonella shedding and enumeration of coliforms. Pigs were euthanized on d 6, 8, 10, and 14. Intestinal and cecal tissue and digesta and mesenteric lymph nodes were sampled and analyzed for Salmonella. Duodenal, jejunal, and ileal mucosal scrapings were sampled for measurement of mucosal TNFα concentrations. Water delivery of DFM prevented a decline in ADG on d 2 to 6 postchallenge compared with the negative control (P < 0.05). Coliform counts tended to be greater (P = 0.09) in the cecum of the DFM treatment group on d 2 postinfection compared with the negative control and acid treatment groups. However, Salmonella prevalence in the feces, gastrointestinal tract, or lymph nodes was not affected by water delivery of acids or DFM. Serum and mucosal TNFα concentrations were not affected by treatment throughout the study with the exception of ileal concentrations on d 4 postchallenge, which were greater in the negative control group compared with all other treatments (P < 0.05). The in-feed antibiotic was the only treatment that reduced Salmonella prevalence and this was localized to the cecum on d 8 postinfection. In conclusion, the DFM and organic acid treatments used in this study offered little or no benefits to pigs infected with Salmonella and should not be considered under the constraints of this study as viable alternatives to in-feed antibiotics in a pathogen challenge situation.

Effect of feeding reduced crude protein and phosphorus diets on weaning-finishing pig growth performance, carcass characteristics, and bone characteristics

Two experiments were conducted to determine the effects of feeding a corn- and soybean meal-based diet (control) or a low nutrient excretion (LNE) diet, formulated with reduced dietary CP and additional synthetic AA, low phytic acid corn, and phytase, on pig growth performance during the grower (BW=32 to 77 kg) and finisher (BW=78 to 126 kg) periods and on carcass and bone characteristics at slaughter. Pigs (32+/-1.3 kg of BW, Exp. 1; 6.7+/-0.27 kg of BW, Exp. 2) were blocked by sex and BW and randomly allotted to a control or LNE diet. Pigs were housed in 4 rooms during the nursery period and in 2 rooms during the grower and finisher periods, with individual and identical ventilation systems. Pigs were phase fed 3 nursery diets for 5 wk (Exp. 2) and phase fed 2 grower and 2 finisher diets for 16 wk (Exp. 1 and 2). Pigs were housed 4 or 5 pigs/pen with 9 pens x sex(-1) x treatment(-1) during the nursery period and 4 or 5 pigs/pen with 5 pens x sex(-1) x treatment(-1) in the grower phase and 2 or 3 pigs/pen in the finisher phase. Individual BW and pen feed disappearance were recorded weekly in the nursery period and every 2 wk in the grower-finisher period. Pigs were scanned ultrasonically at d 34 of the nursery period and wk 8 and 16 of the grower-finisher period to determine backfat depths and LM area. Ten pigs x sex(-1) x treatment(-1) were slaughtered at wk 16 of each experiment to determine carcass characteristics. Overall growth performance was not different during each experiment. However, nursery G:F (control=0.65; LNE=0.60), grower ADG (Exp. 1 and 2), and grower G:F (Exp. 2) were reduced (P<0.05) when the LNE diets were fed. Diet had no effect on 10th-rib carcass data in either experiment. Metatarsal bone ash percentage was reduced (P<0.05) when the LNE diets were consumed in both experiments. Feeding LNE diets resulted in the maintenance of overall growth performance, bone variables, and carcass characteristics. However, further refinements are still required in the nursery and grower phases of pig production to optimize LNE diet use by the swine industry.

Phytase and cholecalciferol supplementation of low-calcium and low-phosphorus diets for pigs

The effects of different levels of calcium, phytase, and cholecalciferol in low-phosphorus diets were studied in individually-penned 20-kg pigs for 28 d. The positive control diet, used in all three experiments, was formulated to contain 6 g Ca and 5.4 g P kg−1. In the first experiment, four barrows and four gilts received one of seven diets arranged as a positive control plus 2 × 3 factorial of phytase (0 or 1, 600 units kg−1) and calcium (3, 4.5 or 6 g kg−1) containing phosphorus at 3.4 g kg−1. Phytase addition increased (P < 0.05) plasma phosphorus concentration, weight gain and gain:feed ratio. Plasma phosphorus, weight gain and gain:feed ratio were linearly reduced (P < 0.05) as dietary calcium level increased in the low-phosphorus diets but not in the phytase-supplemented low-phosphorus diets. The second experiment was similar to the first experiment, except that phytase was reduced to 800 units kg−1 and dietary calcium levels were 2.5, 3, or 3.5 g kg−1. Phytase addition increased (P < 0.05) weight ...

Effect of fermentation of cereals on the degradation of polysaccharides and other macronutrients in the gastrointestinal tract of growing pigs

The main objective of the present investigation was to study the impact of fermentation of cereals on the degradation of polysaccharides and other macronutrients in the small intestine and total tract of growing pigs. Eight pigs (initial BW, 34.5 ± 0.9 kg) were used in a replicated 4 × 4 Latin square design. Pigs were cannulated and housed individually in metabolism pens during sample collection. The 4 cereal-based diets were nonfermented liquid barley (NFLB), nonfermented liquid wheat (NFLW), fermented liquid barley (FLB), and fermented liquid wheat (FLW). The fermented feeds were prepared by storing the dietary cereals (barley and wheat) and water [1:2.75 (wt/wt)] in a closed tank at 25 °C for 2 d, after which 50% of the volume was removed and replaced with an equal amount of fresh cereals and water after each afternoon meal. At the time of feeding (0730 and 1430 h), the remaining dietary ingredients were added. Water was added to the dry nonfermented feeds [1:1 (wt/wt)] immediately before feeding. The fermentation process reduced the amount of DM in both cereals (P<0.001), whereas the amount of DM was similar (P=0.626) between the fermented cereals. There was an interaction of cereal and treatment for ileal flow of DM (P=0.014), OM (P=0.013), and protein (P=0.006), which were less in pigs fed the NFLB than the FLB diets, but unchanged in pigs fed the NFLW and FLW diets. Conversely, the ileal flow of protein was similar (P=0.605) in pigs fed the barley diets (average, 47.5 ± 1.7 g/kg of DMI) and increased with the FLW diet compared with the NFLW diet (43 vs. 35 g/kg of DMI, respectively). Ileal fat and CH(2)O digestibilities were 7.6 (P=0.002) and 8.9% (P<0.001) greater, respectively, when pigs were fed wheat compared with the barley-based diets, and the ileal digestibility of CH(2)O was greater when pigs were fed the fermented than nonfermented diets (86.5 vs. 84.5%, respectively; P<0.001). Fermentation reduced (P<0.0001) the fecal excretion of DM, OM, and protein in pigs fed the barley diet, but not when fed the wheat-based diet (P=0.305). Fermentation had no effect (P=0.243) on the fecal digestibility of nonstarch polysaccharides in either of the cereals but their digestibility was 10.0% greater (P<0.001) in pigs fed wheat than the barley-based diets. In conclusion, fermentation of cereal before feeding altered the dietary composition and influenced flow and composition of polysaccharides and other macronutrients at the ileum and in feces to a larger extent for barley than wheat.

Controlling Salmonella infection in weanling pigs through water delivery of direct-fed microbials or organic acids: Part II. Effects on intestinal histology and active nutrient transport1

The objective of this study was to evaluate the effects of water-delivered, direct-fed microbials (DFM) or organic acids on intestinal morphology and active nutrient absorption in weanling pigs after deliberate Salmonella infection. Pigs (n = 88) were weaned at 19 ± 2 d of age and assigned to 1 of the following treatments, which were administered for 14 d: 1) control diet; 2) control diet + DFM (Enterococcus faecium, Bacillus subtilis, and Bacillus licheniformis) in drinking water at 10(9) cfu/L for each strain of bacteria; 3) control diet + organic acid-based blend (predominantly propionic, acetic, and benzoic acids) in drinking water at 2.58 mL/L; and 4) control diet + 55 mg/kg carbadox. Pigs were challenged with 10(10) cfu Salmonella enterica var Typhimurium 6 d after commencement of treatments. Pigs (n = 22/d) were harvested before Salmonella challenge and on d 2, 4, and 8 after challenge. Duodenal, jejunal, and ileal mucosal tissues were sampled for measurement of villus height and crypt depth. Jejunal tissue was sampled for determination of active nutrient absorption in modified Ussing chambers. Duodenal villus height was greater in pigs fed in-feed antibiotic before infection (P < 0.05). Jejunal crypts were deeper in DFM- and acid-treated pigs on d 4 after infection compared with all other treatments (P < 0.05). Salmonella infection resulted in a linear decrease in phosphorus (P < 0.001) and glucose (P < 0.05) active transport, and an increase (P < 0.001) in glutamine uptake immediately after challenge. Salmonella infection reduced basal short-circuit current (I(sc)); however, water-delivered DFM or organic acid treatments caused greater basal I(sc) on d 2 after challenge than did carbadox. Carbachol-induced chloride ion secretion was greatest in negative control pigs before infection (P < 0.01) and DFM-treated pigs (P < 0.05) after infection. In conclusion, both the DFM and acidification treatments induced increases in basal active ion movement and jejunal crypt depth, which could be interpreted as responses consistent with increased Salmonella pathology, but none of the additives markedly affected intestinal absorptive and secretory function in response to Salmonella challenge.

CASE STUDY: Environmental benefits of ractopamine use in United States finisher swine12

Ractopamine (RAC) is a feed ingredient for use in finishing pigs that increases pork carcass muscle protein and improves production efficiency. A mathematical analysis of the environmental effects of increased rate of gain, improved feed efficiency, and increased carcass leanness was conducted, and for the analysis, it was assumed that RAC was implemented in all finishing pig diets in the United States at 5 or 10 mg/kg of diet, while producing the same amount of pork protein that is currently being produced. The average responses to 5 or 10 mg/kg RAC fed for the last 28 d before market included a 5.3 or 5.9% increase in carcass protein percentage, a 0.31 or 0.81% increase in carcass yield, a 12.0 or 10.9% increase in ADG, a 0.5 or 2.5% reduction in ADFI, and a 9.3 or 14.3% improvement in G:F, respectively, and approximately 3 fewer days to market. Using these assumptions, the current amount of pork could be produced with 5.3 or 6.3% fewer pigs. Because of improved efficiency and the reduction in animal numbers, 2.8 or 3.4 billion fewer kilograms (equivalent to 0.29 or 0.35 million hectares) of corn and 0.16 or 0.34 billion fewer kilograms (equivalent to 0.059 or 0.127 million hectares) of soybeans would be needed for pork production each year, respectively. This reduction in cropland acreage would lead to an annual reduction of 79 or 97.4 million kilograms of fertilizer, 0.8 or 1.05 million kilograms of pesticides (herbicides and insecticides), and 184 or 233 billion liters of water, respectively. In conclusion, the implementation of RAC in swine diets results in a reduced natural resource demand for pork production and improved environmental stewardship.

Impact of Weaning Weight and Early Postweaning Growth of Pigs to Late Finishing Growth When Fed Either Corn- and Soybean Meal-Based Diets or Low Nutrient Excretion Nutrient-Dense Diets

ABSTRACT The BW growth of 1,385 barrows and gilts was evaluated from d-21 weaning to 130 kg BW. The pigs were assigned to a 2×2 factorial arrangement of treatments. The pigs were fed a series of either standard corn- and soybean meal-based control diets or low nutrient excretion nutrient-dense (LNE-ND) diets from 1 wk postweaning to 130 kg BW and assigned to rooms with either deep pit or pull plug-recharge manure storage treatments. The pigs were weighed at weaning, at 7 and 14 d postweaning, and at approximately 2-wk intervals from 28 d postweaning to a mean BW of 130 kg. Mixed model nonlinear equations including pig-specific random effects were evaluated for the generalized Michaelis-Menten function. The serial postweaning BW data were fitted to a mixed model generalized Michaelis-Menten equation. Relationships of weaning BW to late finishing BW and days to 125 kg BW were different for each dietary treatment. Late finishing BW and days to 125 kg BW had nonlinear relationships with weaning BW for pigs fed the LNE-ND diets and had linear relationships for pigs fed the control diets. The predicted changes in subsequent BW of the LNE-ND diets per kilogram of change in weaning BW were greater for pigs with the lightest weaning BW than for pigs with average to above-average weaning BW. Across both dietary treatments, pigs with greater weaning BW and greater early postweaning ADG required fewer days to achieve target market BW.

CASE STUDY: Implementation of feed management as part of whole-farm nutrient management

ABSTRACT In 2006, the USDA Natural Resources Conservation Service (NRCS) Conservation Innovation Grant program funded a project to develop the infrastructure for the systematic development and implementation of the USDA-NRCS Feed Management (FM) Conservation Practice Standard 592 (CPS 592). The overall goal of CPS 592 is to encourage adoption of FM practices that can have a positive impact on soil, water, and air quality. Implementation documents, templates, decision aid tools, and supporting fact sheets were developed for the species of beef, dairy, poultry, and swine. Specific objectives of the project were to 1) assist USDA-NRCS staff and agricultural professionals to increase their understanding of FM and its impacts on environmental sustainability of livestock and poultry operations, 2) improve the proficiency of agricultural professionals in the development and implementation of a FM plan as part of a Comprehensive Nutrient Management Plan, 3) provide the American Registry of Professional Animal Scientists with certification exams, and 4) provide methodology on how to assess the financial implications of different ration strategies on whole-farm nutrient balance and economics of use of manure nutrients at agronomic rates. Implementation of CPS 592 is described for the states of California, Maryland, Pennsylvania, and Wisconsin.