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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, Salmonellainfection and shedding, and intestinal microbial populations after intranasal inoculation of SalmonellaTyphimurium (1010cfu/pig). Pigs were challenged with Salmonella6 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 109cfu/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 Salmonellashedding 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, Salmonellaprevalence 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 Salmonellaprevalence 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 Salmonellaand should not be considered under the constraints of this study as viable alternatives to in-feed antibiotics in a pathogen challenge situation.

A completely random design experiment was conducted to determine the effect of dietary arsonic acids on the performance of laboratory swine waste anaerobic digesters. Fortified corn soybean meal diets containing no arsonic acids (control), 100 ppm arsanilic acid or 75 ppm roxarsone were fed to growing-finishing pigs. Fresh waste (including urine) from all treatments were collected daily for 74 days and loaded at a rate of 2.4 kg volatile solids/m3into nine 25-liter anaerobic digesters heated to 34 C with continuous agitation and total gas collection. After a 60-day acclimation period, daily gas production and composition and nutrient composition data were obtained from the anaerobic digesters. Inclusion of the arsonic acids in swine diets reduced dry matter and volatile solids content. Dietary arsonic acids also increased nitrogen in the ammonium form. Alkalinity was high in all the digesters; however, arsonic acids decreased alkalinity. Dietary arsonic acids reduced the ratio of methane to carbon dioxide in the gas compared to the control. Significant amounts of arsenic accumulated in the digesters. Acetic, propionic and butyric acids were increased by roxarsone, and arsanilic acid increased the butyric acid concentration over the percentage in both the roxarsone and control digesters.

Selected microbial organisms were counted in swine wastes during three studies in which the primary objective was to investigate the effects of feed additives and waste management systems on swine waste composition. Dietary salt (NaCl) levels (.2, .5%), dietary arsanilic acid levels (0, 100, 200 ppm), supplemental copper levels (0, 125, 250 ppm) and waste management systems (oxidation ditch, anaerobic deep pit, anaerobic lagoon) were compared in this series of studies. Dietary salt level did not affect total coliform and fecal streptococci concentrations in swine waste. Supplemental copper and arsanilic acid increased total coliform counts (dry matter basis) in anaerobic pit wastes over counts observed with the control. Salmonella sppconcentrations were increased in the anaerobic pit waste at the end of the 104-day feeding trial, especially with the 250-ppm copper diet. Staphylococci spporganisms were not affected by supplemental copper. In all studies, concentrations of the microorganisms cultured were higher in freshly excreted waste than in waste stored and partially treated in the waste systems studies. Temperature, dilution and waste handling systems had some effects on microbial populations

To determine whether manure gases can influence onset of puberty in gilts, 42 crossbred gilts were reared from 10 to 40 wk of age on concrete slats over a 1.22-m deep pit that was drained and refilled with clean water biweekly (clean group). Forty-one gilts were reared over a similar type pit where manure was allowed to accumulate (control group). Treatments were in two separate rooms of the same building with similar feeding, water, floor space, lighting and room temperature. Ventilation fans with timer controls in each room were set so fans in the clean environment ran twice as long as fans in the control environment. Aerial concentrations of ammonia in the control room were fourfold higher than in the clean room (21 vs 5 ppm), while aerial concentrations of hydrogen sulfide were similar. Average daily gain and feed efficiency were similar for both groups [.69 vs .72 kg/d (P=.3D and 1.61 vs 1.54 kg feed/kg gain (P=.52)] . From 20 to 40 wk of age, all gilts were exposed to a mature boar three times weekly, utilizing four boars in rotation. Blood samples were collected weekly from each gilt by venipuncture and analyzed for progesterone to establish time of first ovulation. A greater proportion of gilts in the clean group attained puberty by 24 to 26 wk (P<.05) and 27 to 29 wk of age (P<.10) compared with the control group. At 20, 26 and 32 wk of age, 15 prepubertal gilts from each treatment were fitted with jugular cannulas, and blood samples were drawn at 20-min intervals for 4 h. Mean serum concentration of luteinizing hormone (LH) increased (P<.05) as gilts approached puberty but were not different (P=.60) between groups. No difference in frequency of LH secretory spikes (P=.41) or in mean serum concentrations (P=.56) of follicle stimulating hormone (FSH) was found as gilts approached puberty or between groups. Frequency of FSH secretory spikes did not increase (P=.43) as gilts approached puberty but was higher (P<.05) in control gilts. All gilts were slaughtered at 40 wk of age. Nasal turbinate and lung condition standard scores were similar between control and clean treatment groups (P=.20 and P=.46, respectively). In conclusion, a greater proportion of gilts reared in the clean environment reached puberty by 29 wk of age, although secretory patterns of serum LH and FSH were not altered.

Animal wastes were regarded as valuable fertilizer resources 75 yr ago. With the advent of intensive animal production systems the wastes were regarded as pollutants and nuisances. During the past few years, again, the wastes have been recognized as valuable resources. The primary uses of animal wastes are as sources of plant nutrients (fertilizer), animal nutrients (feedstuffs) and feedstock for energy (methane) generation. The wastes are valuable sources of plant nutrients and provide organic matter which is useful to improve soil structure. Due to the usually high fiber content and frequently high levels of non-protein nitrogen, wastes are more valuable for feeding ruminants than non-ruminants. Animal wastes should be processed prior to feeding to enhance palatability and destroy potential pathogens. A number of processes have been used successfully. There is minimum health hazard from feeding processed animal wastes if withdrawal periods are used for waste containing medicinal drugs. The wastes can be used for methane (CH4) generation by anaerobic fermentation. The wastes are most valuable when used as feeds for animals and least valuable when used for CH4generation. Their value for CH4generation is enhanced when the residue is used as feedstuffs or fertilizer. Considerable amounts of wastes are being utilized for feed, fertilizer and CH4generation, but efficiency of these uses has not been optimized. Research needs on animal waste should include multidisciplinary efforts applying principles of systems analysis. Additional research is needed to determine how to control nutrient losses effectively during storage and from soil application. Nitrogen conservation deserves special attention. Research is needed on preservation of waste to be used for feeding. Efficiency of nutrient utilization, especially minerals, deserves attention. The main research needs in CH4generation are in the development of equipment to improve efficiency and on . more efficient utilization of the residue.

An experiment was conducted to determine the effect of copper sulfate in swine diets on fresh waste composition and on decomposition of the waste stored in anaerobic pits. Vitamin and mineral fortified corn-soybean meal diets with 0, 125 and 250 ppm copper were fed to growing-finishing pigs (18 to 91 kg) in spring and summer trials with daily fresh waste collection and addition to anaerobic pits.Copper concentrations (wet basis) in the anaerobic pits from pigs fed the 0, 125 and 250 ppm copper diets for trial I were 3.15, 34.27 and 44.63 ppm, respectively. For trial II, copper concentrations were 3.55 and 48.61 ppm, respectively, for diets containing 0 and 250 ppm copper. Average elemental copper excretion for the 250 ppm copper diets ranged from 433 to 490 mg per head per day.The presence of copper sulfate in swine diets did not affect fresh waste composition. Copper sulfate decreased the decomposition of the waste in anaerobic pits as shown by the greater reduction of dry matter and volatile solids in waste from pigs fed no copper sulfate. Dry matter content was reduced 65% in anaerobically stored waste from pigs fed 0 ppm copper, while the dry matter content was reduced only 55 and 51% from pigs fed the 125 ppm and 250 ppm copper diets in trial I. In trial II the dry matter was reduced 41% for the 0 ppm stored waste and 31% for the 250 ppm stored waste.

A complete random design experiment was conducted to determine the effect of dietary arsonic acids on swine waste composition and decomposition in anaerobic pits. Vitamin and mineral fortified corn-soybean meal basal diets with either 75 ppm roxarsone or 100 ppm arsanilic acid were fed to growing-finishing pigs (14 to 91 kg) with daily fresh waste collection and addition to model anaerobic pits.Arsonic acids in the diet influenced (P<.001) pH, dry matter, volatile solids, Kjeldahl nitrogen, ammonium nitrogen and arsenic content in the model anaerobic pits. Compared to the control there was a significant decrease in dry matter and volatile solids. Arsanilic acid in the diet increased (P<.001) the amount of nitrogen in the ammonium form compared to the control and roxarsone diet. Arsanilic acid increased (P<.05) the acetic acid content in the anaerobic pit compared to the control when expressed as a percentage of total volatile fatty acids measured.Elemental arsenic losses to the atmosphere were measured in anaerobically stored waste from all treatments.

A complete random design experiment was conducted to determine the effect of arsanilic acid in swine diets on fresh waste production and composition and on decomposition of the waste stored in anaerobic pits. Vitamin and mineral fortified corn-soybean meal diets with 0, 100 or 200 ppm arsanilic acid were fed to growing-finishing pigs (14 to 91 kg) in winter and summer trials with daily fresh waste collection and addition to anaerobic pits.Average daily total waste production (wet basis) per pig, including hair, dust, wasted feed, waste water and excreta, was 3.8 kg during the winter trial and 4.8 kg during the summer trial. Average elemental arsenic excretion ranged from 35.7 mg to 62.8 mg per head per day. Arsenic concentrations (wet basis) in the anaerobic waste from pigs fed the 0, 100 and 200 ppm arsanilic acid diets for both trials were .54, 6.29 and 11.23 ppm, respectively.The presence of arsanilic acid in swine diets did not affect fresh waste production or composition. Arsanilic acid did enhance the decomposition of waste as shown by the reduction of dry matter and volatile solids in waste from arsanilic acid fed pigs. Dry matter content was reduced more than 60% in each trial in anaerobically stored waste from pigs fed arsanilic acid, while the dry matter content was reduced 23% and 39% in the waste from pigs fed the control diet. The presence of arsenic in the waste resulted in the retention of more total nitrogen (dry basis) and nitrogen in the ammonium form compared to waste with no arsenic but did not affect phosphorus, potassium and nitrate nitrogen levels.

A 2-year experiment was conducted to study the effects of .2 or .5% salt (NaCl) in growing-finishing swine diets and aerobic (oxidation ditch) or anaerobic (deep pit) liquid waste systems on swine performance and waste nutrient composition.Neither dietary salt content nor waste handling system affected pig gains or feed conversion. Waste from pigs fed .5% salt contained higher sodium levels than waste from pigs fed .2% salt. During the study, the sodium level increased in the waste pits beneath pigs fed the .5% salt diet, whereas the sodium level in the waste pits beneath pigs fed the .2% salt diet remained relatively constant.Aerobically treated waste contained lower dry matter and higher dissolved oxygen concentrations, had higher pH and temperature on a wet basis, and lower ammonium nitrogen and higher nitrate nitrogen, potassium and sodium concentrations on a dry weight basis that anaerobic waste. The average percentage of ammonium nitrogen to total Kjeldahl nitrogen was 42% in aerobic pits, 53% in anaerobic pits, 45.5% in waste from pigs fed .5% salt diets and 49.5% in waste from pigs fed .2% salt diets.Copper and phosphorus levels in wastes were directly related to the dry matter content of the waste. Sodium and potassium concentrations (dry weight basis) were higher in aerobically treated waste from pigs fed the .5% salt diet compared to anaerobically treated waste from pigs fed the .2% salt diet.

Balance trials and a rumen and blood study were conducted to evaluate nitrogen utilization in feeder lambs fed alfalfa preserved as hay, low-moisture and high-moisture silages. Utilization of nitrogen by lambs fed hay was greater than that from fermented forages as shown by higher dry matter and nitrogen digestibilities and nitrogen balance. Utilization of nitrogen from high moisture silage was intermediate and from low moisture silage the lowest. Considerable nutrient changes were observed in alfalfa during the fermentation process. Total nitrogen content changed to a more soluble and nonprotein nitrogen form. Soluble nitrogen as a percentage of total nitrogen changed from 32% for hay to 52% and 71% for low- and high-moisture silages, respectively. Soluble carbohydrate percentage decreased from 7.2% for hay to less than 3% for the fermented forages. Rumen ammonia and blood urea values were significantly higher (P<.05) in hay-fed lambs than in lambs fed silages. Values for blood urea and plasma alpha-amino nitrogen and rumen ammonia were affected by the intake, digestibility and the amount of readily available nitrogen and energy in the forages.