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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:
Sexing of sperm using single stranded DNA oligonucleotides
Posted in: Ontario Pork, Pork Insight Articles by admin on August 15, 2012 | No Comments
The sex of an animal can have large economic implications on a large producing farm. One example is an egg farm where the male sex does not contribute to production therefore half the offspring is undesirable. The ability to control sex can have great benefits to genetic progress and herd management. The objective of this study was to test new methods for identification sex specific markers on the sperm surface which can be used to develop new sperm sexing technology. The researchers used aptamers to help detect slight molecular signatures within biological systems. A procedure was developed to select two aptamer families, X- and Y. The X- and Y-aptamer families were found to have increased binding to X- and Y-sorted sperm. Current results have shown that binding of a X-aptamer might be sex-specific but more tests will have to be done to make sure. If the specific X-aptamer was found to be sex-specific it would be the first confirmed presence of a sex-specific membrane marker on mammalian sperm. This would have large scientific implications as well as commercial benefits to herd management.
Nitrogen transformations and losses following application of liquid swine manure to agricultural soils as determined by 15N tracer methods
Posted in: Ontario Pork, Pork Insight Articles by admin on August 13, 2012 | No Comments
Hog manure can be an important supplier of N to soils but mismanagement of the manure application can lead to air and water pollution. Manure loss is known to happen but a more in-depth look at where losses are occurring can help minimize them. In this study liquid manure was used mixed with 15N to track N transformations and to directly measure manure N recovery in crops, retained in soil, and total losses by leaching and gaseous emissions. The experiment took place at two sights each of which had different soil characteristics and draining systems (one was sloped, the other not). The manure was enriched with 15N by feeding it to the pigs. Manure was spread in three different time periods: late fall, spring, and side dress in June. Several rates of inorganic N were applied along with one control with no manure or fertilizer. All the plots were planted with corn, and regular soil and water sampling from drainage was carried out. Also samples of the corn were taken. For the manure applied in late fall there was 29% loss of manure N recorded over the winter at one sight. Sights which had manure applied (all but the control) produced water samples that tested positive for Nitrate N, suggesting that manure N was leaching into the drainage water. The amount of N absorbed by corn was 15% for the plot spread in late fall, for the side dressed and spring application the corn absorption rate was 30-35%. This difference can be explained by the difference in N loss, late fall having a loss of 35-40% compared to that from spring, 15 – 22% loss, and side dress applications 7 – 9% loss. Clearly, spring application, particularly as side-dress has an advantage in terms of reducing environmental losses. The actual impact of environmental losses is dependent on the form of N lost, as gases or in leaching.
Tryptophan Requirement of Pregnant Sows
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This study was conducted to determine the Trp requirement in EG and LG using the indicator AA oxidation method. The same 6 2nd parity sows were studied in EG (d 35 to 53) and in LG (d 92 to 111) at a constant feed amount of 2.4 kg/d. Each sow received 6 diets based on corn, corn starch and sugar in both EG and LG. Diets in EG contained Trp at 20, 40, 60, 80, 100 and 120 % of the Trp requirement (2.5 g/d) in EG, for sows of similar body weight, maternal gain and litter size, and 60, 80, 100, 140, 160 and 180% in LG. Sows were fed 2 mg/(kg BW·h) of L[1-13C]Phenylalanine (Phe) over 4 h in 8 ½-hourly meals. Expired CO2 and plasma free Phe were analyzed for 13C enrichment above background. Requirements were determined as the breakpoint in 2-phase nonlinear models. Sows grew from 167.7 kg (SE 3.93) at breeding to 211.9 kg (SE 5.18) post farrowing. The sows had litters of 14.5 piglets (SE 0.43) weighing 19.0 kg (SE 1.41) at birth. The Trp requirement was greater (P = 0.002) by 52% in LG (2.6 g/d) compared to EG (1.7 g/d). Phe oxidation (P = 0.029) and body protein breakdown (P = 0.017) decreased from EG to LG. Phe retention and oxidation responded quadratically (P = 0.038) to increasing Trp intake. The increase (P = 0.001) in Phe retention from EG (2.94 g/d) to LG (8.28 g/d) agreed with a gain of 1 g/d N per fetus in LG and indicated that maternal protein gain was similar in EG and LG. Phase feeding of 2 diets with different Trp contents is necessary to balance Trp and energy intake with the changing Trp and energy requirements in pregnancy.
Isoleucine Requirement for Maintenance
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The objective of this study was to determine the Isoleucine (Ile) requirement for maintenance using the indicator AA oxidation method. Each of 6 sows, non-pregnant after their 4th litter, received 6 diets based on corn, corn starch and sugar at a mean intake of 2.19 kg/d (SE 0.014). Diets were calculated to provide Ile at 10, 20, 30, 50, 60, and 70 mg/kg0.75 body weight (BW). Leucine intake was 65 mg/kg0.75 BW, valine intake 62 mg/kg0.75 BW. Sows were confined in respiration chambers overnight before each oxidation study to determine fasting energy expenditure. The 13C background in expired CO2 was determined for 1.5 h. Sows were fed 2 mg/(kg BW·h) of L[1-13C]Phenylalanine (Phe) over 4 h in 8 ½-hourly meals. Requirements were determined as the breakpoint in indicator AA oxidation in 2-phase nonlinear models. Mean sow BW was 219 kg (SE 2.41). The daily gain of -0.199 kg/d (SE 0.098) during the 18-d study was not different from zero (P = 0.10). The Ile requirement was 35 mg/d×kg0.75 BW (P= 0.001). Overall Phe retention was less than zero (-0.92 g/d, SE 0.125, P = 0.001) but not different from zero (P = 0.14) for Ile intake above the requirement at -0.53 g/d (SE 0.334). Fasting heat production was 19.3 MJ/d (SE 0.41) or 334 kJ/kg0.75 BW (SE 8.5). Heat production was 31.8 MJ/d (SE 0.19) and energy retention was -0.14 MJ/d (SE 0.054), which was not different (P = 0.80) from zero. The fasting and fed respiratory quotient was 1.0 (SE 0.02) and 1.02 (SE 0.02), respectively. Because energy and protein retention were not different from zero, the value of 35 mg/d×kg0.75 represents the Ile maintenance requirement. This indicates that AA maintenance requirements are greater for modern pigs but their ratios remain similar.
Effects of dietary true digestible calcium to phosphorus ratio on growth performance and efficiency of calcium and phosphorus utilization in growing pigs fed corn and soybean meal-based diets
Posted in: Ontario Pork, Pork Insight Articles by admin on August 12, 2012 | No Comments
Objective was to determine the true fecal digestibility of calcium and phosphorus in the growing pig fed corn and soybean meal (SBM) based diets. Emphasis was put on the calcium to phosphorus ratio and how it relates to growth performance of the growing pig. Results showed no average daily gain differences between diets containing different calcium to phosphorus ratios. In conclusion, true fecal digestible calcium to phosphorous ratios of 0:9:1 to 1:0:1 showed optimal gain to feed ratios as well as fecal digestibility of phosphorus and utilization of phosphorus by growing pigs fed corn SBM based diet.
Ch. 16 – Swine Nutrition and Environment
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Chapter 16 of Sustainable Swine Nutrition. Sections: Dietary origins of the major environmental concerns, Emissions of greenhouse gases, Emission of ammonia, Leaching of nitrate and runoff of chromium, Food chain and ecosystem concerns with heavy metal minerals, Runoff of soluble P from manure, Transmission of pathogenic microbes, Development of antimicrobial resistance, Biogenesis of major manure volatile odorous compounds, Airborne pollutants from swine production units, Strategies for mitigating the major environmental concerns and more.
Isoleucine Requirement of Pregnant Sows
Posted in: Ontario Pork, Pork Insight Articles by admin on | No Comments
The objective of this study was to determine the Isoleucine requirement in early (EG) and late (LG) gestation using the indicator AA oxidation method. Each sow received 6 diets based on corn, corn starch and sugar in both EG and LG at constant amount of 2.5 kg/d. Diets in EG contained Ile at 20, 40, 60, 80, 100 and 120 % of the Ile requirement (6.2 g/d, NRC 1998) for sows of similar body weight (BW), expected maternal gain and litter size, and 60, 80, 100, 140, 160 and 180% in LG. Dietary valine and leucine contents were 3.5 g/kg and 4.3 g/kg in EG and 5.6 g/kg and 6.9 g/kg in LG, respectively. Ile requirements of adult sows increased more from EG to LG than tryptophan requirements in young, growing sows, and were driven mainly by maintenance in EG and by fetal growth in LG. The AA supply is more critical in LG than energy intake for adult sows. Therefore, phase feeding during gestation is necessary to meet the sows’ requirements.
Molecular approaches toward improving Fusarium graminearum resistance in corn
Posted in: Ontario Pork, Pork Insight Articles by admin on August 9, 2012 | No Comments
Fusarium causes ear rot in corn and commercial strains of corn have little or no resistance to the disease. Environmental factors largely control the spread of the disease which can reach epidemic levels and cost Canadian farmers millions in potential profit. If growing conditions are poor, mycotoxins can be wide spread in crops, the mycotoxins are difficult to break down and cook out so they remain in animal feed and human food. Even small doses in pig feed can extend the time it takes pigs to reach market weight, and larger levels can cause reproductive problems. It is difficult to create resistance to fusarium because the disease is so variable, and even shows up in highly controlled conditions. This makes it difficult to find resistant genes in the plant. The use of molecular makers aid in finding good genes as they can be taken off of seedlings and analyzed in a lab setting. This project attempts to find the gene that is resistant to ear rot and to develop gene based markers for ear rot. The experiment was able to identify several resistant genes which were converted to markers that can easily be scored to allow rapid introgression into elite corn germplasm. The short-term outcome of the work is that it identified a set of gene-based markers linked to Fusarium resistance that can be used by plant breeders to select for resistance in natural sources. The identification of genes associated with resistance could also be exploited to develop transgenic plants over expressing these genes that may have enhanced resistance to Fusarium.
Pilot Scale Treatment of Liquid Hog Manure using an Electrochemical Reactor
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This article is a follow up report from an Ontario Pork project done in 2004. Three areas of work are looked at, the first being work using laboratory scale micro-reactors that demonstrated that chemical parameters like total organic carbon decrease upon electorolysis at the same rate as improvements in odour quality and odour intensity. Electrolysis has a bactericidal role, which explains why treated liquid manure seems stable with respect to reversion to a malodorous state. The second work being looked at is the results being replicated using a one liter scale reactor, made with cheaper materials and whole manure was used instead of liquid manure. Lastly, a 27 liter tank being stirred continuously was constructed based on the design of the one liter tank, and it has been tested both in the lab and in a field research station.
In growing pigs, chlortetracycline induces a reversible green bone discoloration and a persistent increase of bone mineral density dependent of dosing regimen
Posted in: Ontario Pork, Pork Insight Articles by admin on August 8, 2012 | No Comments
Researchers attempted to find out how chlortetracycline, when given to pigs, impacted the pigs bone color and bone density. Pigs were either put on a diet that consisted of no chlortetracycline or with 800ppm of chlortetacycline. The pigs started on the diet at either 28 days old or 84 days old. Pigs were put on the diet for either 28 days or 56 days. Discoloration of the lumbar vertebrae and bone density were assessed from randomly selected pigs every 28 days until the pigs reached 168 days of age. The longer the pigs were held on the medicated diet and the older they were when put on the diet, saw increased chances of bone discoloration. Bone density improved the longer the pigs were held on the medicated diet. The researchers concluded that the bone discolorationon was reversable and application of the medicated diet caused permanent bone density improvement.