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Prairie Swine Centre is an affiliate of the University of Saskatchewan
Prairie Swine Centre is grateful for the assistance of the George Morris Centre in developing the economics portion of Pork Insight.
Financial support for the Enterprise Model Project and Pork Insight has been provided by:
Nitrogen transformations during biological aerobic treatment of pig slurry: effect of intermittent aeration on nitrous oxide emissions
Posted in: Environment by admin on January 1, 2002 | No Comments
Low-Phytic Acid Barley Improves Calcium and Phosphorus Utilization and Growth Performance in Growing Pigs
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Thirty-five crossbred barrows averaging 13.5 kg starting BW were used in a 35-d experiment to compare the availability of P and the nutritional value of two near-isogenic progeny of the barley cultivar ‘Harrington’. Low-phytic acid barley (LPB, 0.35% total P, 0.14% phytic acid P) was homozygous for the low-phytic acid 1-1 allele, and the normal barley (NB, 0.35% total P, 0.24% phytic acid P) was homozygous for the normal allele of that gene. Pigs were fed individually twice daily in metabolism pens. Barley was the only source of phytate in semipurified diets, 1 to 3. Diet 1 contained 75% NB, 0.14% estimated available P (aP), and 0.50% Ca. Diet 2 contained 75% LPB, 0.22% aP, and 0.50% Ca. No inorganic P (iP) was added to Diets 1 and 2 in order to measure the animal response to the different concentrations of aP in these cultivars. Diet 3 was NB Diet 1 supplemented with iP to equal the concentration of aP in LPB Diet 2. Practical barley-soybean meal (SBM)-type diets, NB Diet 4 and LPB Diet 5, were formulated to meet all minimum nutrient requirements, and contained 0.30% aP and 0.65% Ca. For the semipurified diets, pigs fed LPB Diet 2 had higher (P less than or equal to 0.05) bone ash weight, bone breaking strength, P absorption and retention, and Ca absorption and retention compared with pigs fed NB Diet 1, with a trend (P = 0.10) for pigs fed LPB Diet 2 to have a higher ADG and gain:feed ratio than pigs fed NB Diet 1. However, pigs fed LPB Diet 2 or NB Diet 3 were not different (P greater than or equal to 0.3) in growth performance, fresh bone weight, fat-free dry bone weight, bone ash, bone breaking strength, or N utilization. This indicates that LPB and NB were equal in nutritional value after supplementation of NB with iP to equal the estimated aP in LPB. For the practical barley-SBM diets, there were no differences (P greater than or equal to 0.4) between pigs fed NB Diet 4 or LPB Diet 5 for growth performance, fresh bone weight, bone breaking strength, the percentages of P and Ca utilization, or N, DE, and ME utilization. The use of LPB in pig diets reduced P excretion in swine waste by 55% and 16% in our semipurified and practical diets, respectively, compared with NB. Using our in vitro procedure designed to mimic the digestive system of the pig, the availability of P for pigs was estimated at 52% for LPB and 32% for NB.
Nutrient composition of Kansas Swine Lagoons and Hoop Barn Manure
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Calculating Direction-dependent Separation Distance by a Dispersion Model to avoid Livestock Odour Annoyance
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Using a dispersion model to calculate ambient odour concentrations, the separation distance between
livestock buildings and residential areas is defined by the odour impact criteria incorporating the probability of exceeding a pre-selected odour threshold in odour units (OU) per cubic metre. The dynamic Austrian odour dispersion model (AODM), a Gaussian model, is used to calculate the direction-dependent separation distances for several combinations of these two values, which represent the protection level of various land use categories. The calculated direction-dependent separation distances are a function of the prevailing wind velocity and atmospheric stability conditions. At a site in the Austrian North-alpine foreland, the directiondependent separation distance for a 1000-head pig unit (calculated on the basis of a 2-year time series of meteorological data) for pure residential areas (3% probability of threshold exceedance over the year for an odour threshold of 1OUm3) lies between 99 m(for northerly winds with a probability of less than 3% per year) and 362 m(for westerly winds with a probability of 34%). For themain wind directions, West and East, odour sensation can be expected more often for higher wind velocities and a neutral or stable atmosphere
around sunset. North and South winds show the typical diurnal variation of a local valley wind system with predominantly northerly daytime up-valley and southerly nighttime down-valley winds. Odour sensation is therefore most likely around noon for North winds and during nighttime for South winds.
Odour Generating Bacteria in Swine Manure and Composted Swine Manure Identification by Molecular Techniques
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One of the most important objections to the expansion of the Manitoba livestock industry is the problem of odour from animal wastes. Bacteria ferment manure under anaerobic conditions to produce most of the objectionable odour compounds. Little is known about the microbiology of anaerobic bacteria in manure. Microbiological research has relied on conventional techniques such as growing the bacteria and measuring biochemical properties. Techniques that rely on growing bacteria underestimate the population and the diversity of species of microorganisms present in manure. Most bacterial species present in an environment such as manure cannot be grown. If we cannot culture these bacteria, we cannot measure their contributions to odour compound generation. To overcome this problem, new techniques from the field of molecular genetics have been applied in this study. For each sample, the DNA from all of the bacteria was isolated. The polymerase chain reaction (PCR) technique was applied to produce enough of a specific gene which every bacterium carries, the 16S rRNA gene. While every bacterium carries this gene, the precise sequence of nucleotides of the gene varies amongst different species and can be used to identify a particular bacterium. Nucleotides are the individual building blocks of all genes. Determining the nucleotide sequences is expensive so, in this study, a technique was first used to determine how many different 16S rRNA genes were present. Once this was accomplished, then the most abundant genes actually had their individual nucleotide sequences determined. The technique to indicate the number of different 16S rRNA genes present is called denaturing gradient gel electrophoresis. This technique is based on the principle that each different type of 16S rRNA gene a
Effects of Dietary Proetin and Oathull Fiber on Nitrogen Excretion Patterns and Postprandial Plasma Urea Profiles in Grower Pigs
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The objectives of this study were: 1) to determine if dietary protein reduction or oathull fiber inclusion would reduce urinary N excretion in grower pigs, 2) to determine if plasma urea could predict urinary N excretion among diets differing in protein and fiber content with an expected range in N excretion patterns, and 3) to determine the postprandial time point to sample blood for the best prediction. Three dietary protein concentrations (high, 19.7; medium, 16.9; low, 13.8%) and two fiber levels (high, 5.0; low, 3.6% crude fiber) were tested in a 3 x 2 factorial arrangement. Diets (wheat, barley, soybean meal; oathulls as fiber source) were formulated to 3.25 Mcal of digestible energy (DE)/kg and 2.2 g of digestible lysine/Mcal DE for low- and medium-protein diets, and 2.4 g/Mcal of DE for high-protein diets, and supplemented with lysine, methionine, tryptophan, threonine, isoleucine, or valine to meet an ideal amino acid profile. Pigs (32 +/- 3.4 kg; n = 42) were housed in metabolism crates for 19 d. On d 10 or 11, catheters were installed by cranial vena cava venipuncture. Daily feeding allowance was adjusted to 3x maintenance (3 x 110 kcal DE/kg body weight(0.75)), and was fed in two equal meals. Feces and urine were collected from d 15 to 19. Five blood samples were collected in 2-h intervals on d 16 and 19. Fecal, urinary, and total N excretion was reduced linearly with a reduction of dietary protein (P < 0.001); the reduction was greater for urinary (48%) and total N excretion (40%) than for fecal N excretion (23%). Similarly, the ratio of urinary to fecal N was reduced linearly with a reduction of dietary protein (P < 0.001). Retention of N (g/d) was reduced linearly. but N retention as a percentage of N intake was increased linearly with a reduction of dietary protein (P < 0.001). The addition of oathulls did not affect N excretion patterns and plasma urea (P > 0.10). Dietary treatments did not affect average daily gain or feed efficiency (P > 0.10). A dietary protein x time interaction affected plasma urea (P < 0.001). For medium- and high-protein diets, plasma urea increased postprandially, peaking 4 h after feeding, and then decreased toward preprandial levels (P < 0.05). Plasma urea did not alter postprandially for the low-protein diet (P > 0.10). Urinary N excretion (g/d) was predicted by 3.03 + 2.14 x plasma urea concentration (mmol/L) at 4 h after feeding (R2 = 0.66). Plasma urea concentration is indicative of daily urinary N excretion and reduction of dietary protein is effective to reduce total and urinary N excretion.