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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:
Selection and Validation of Reference Genes for miRNA Expression Studies during Porcine Pregnancy
Posted in: Ontario Pork, Pork Insight Articles by admin on December 12, 2011 | No Comments
MicroRNAs comprise a family of small non-coding RNAs that modulate several developmental and physiological processes including pregnancy. Their ubiquitous presence is confirmed in mammals, worms, flies and plants. Although rapid advances have been made in microRNA research, information on stable reference genes for validation of microRNA expression is still lacking. Real time PCR is a widely used tool to quantify gene transcripts. An appropriate reference gene must be chosen to minimize experimental error in this system. A small difference in miRNA levels between experimental samples can be biologically meaningful as these entities can affect multiple targets in a pathway. This study examined the suitability of six commercially available reference genes (RNU1A, RNU5A, RNU6B, SNORD25, SCARNA17, and SNORA73A) in maternal-fetal tissues from healthy and spontaneously arresting/dying conceptuses from sows were separately analyzed at gestation day 20. Comparisons were also made with non-pregnant endometrial tissues from sows. Spontaneous fetal loss is a prime concern to the commercial pork industry. Our laboratory has previously identified deficits in vasculature development at maternal-fetal interface as one of the major participating causes of fetal loss. Using this well-established model, we have extended our studies to identify suitable microRNA reference genes. A methodical approach to assessing suitability was adopted using standard curve and melting curve analysis, PCR product sequencing, real time PCR expression in a panel of gestational tissues, and geNorm and NormFinder analysis. Our quantitative real time PCR analysis confirmed expression of all 6 reference genes in maternal and fetal tissues. All genes were uniformly expressed in tissues from healthy and spontaneously arresting conceptus attachment sites. Comparisons between tissue types (maternal/fetal/non-pregnant) revealed significant differences for RNU5A, RNU6B, SCARNA17, and SNORA73A expression. Based on our methodical assessment of all 6 reference genes, results suggest that RNU1A is the most stable reference gene for porcine pregnancy studies.
Impact of Debt on Ontario Swine Farms
Posted in: Ontario Pork, Pork Insight Articles by admin on November 1, 2011 | No Comments
Canadian farmers carry a lot of debt, total farm debt for all Canadian farms was 66.4 billion in 2010. Pork producers make up about 6% of this debt, with each farms average debt being $850 435. Hog producers faced difficult financial times from 2006-201o where they experienced sustained losses which increased their debt loads. Fortunately interest rates have remained low for the same period helping farmers avoid paying more interest. But now with speculation of interest rates rising, farms carrying large debt loads could find themselves once again in financial trouble. This paper attempts to help Ontario pork producers understand how they compare to other producers in different regions and of other commodities in terms of debt levels and their ability to meet financial repayments should interest rates rise from their current historically low levels. Some objectives of this paper are to: 1) Calculate Ontario industry averages for debt‐related financial ratios using a variety of data sources. 2) Calculate financial ratios for pig producers in other provinces and the U.S. 3) Identify differences, if any, in farm debt repayment ability for the various production stages or for different farm sizes. 4) Develop a tool that producers and industry partners can use to input individual farm data that allows for comparison to the industry averages. Using multiple data sources the authors were able to determine that Ontario hog farms have higher debt to asset ratios than those of Manitoba and the US but still lower than farms in Quebec. Ontario pork farsm have more long term structured debt than other farm types in Ontario. Debt to total revenues averaged 1.25 during the period of 2007-2009 which is higher than all other Ontario farm types except dairy. Debt to equity ratios, % equity positions, and current ratios all worsened in 2009 compared to the 2003 to 2008 levels.Return on assets was in the 3‐7% range from 2003 to 2008 but dropped to slightly above 0% in 2009. The data revealed many other statistics about how debt loads increased from 2006. Some summaries that the authors came up with include: Ontario swine operations have a total debt and interest expense of $1.1 billion. Larger farmers carried more debt, but debt was not tied to profit. On an aggregate industry level, debt levels and debt servicing requirements on average do not appear to be the major determining factor in profitability. For farms of any gross revenue size or production type it is important to not extend their debt servicing capacity beyond levels that are sustainable.
Enhancement of Immune Response in Piglets
Posted in: Ontario Pork, Pork Insight Articles by admin on October 22, 2011 | No Comments
This study looks at the variation in immune response (IR) of pigs in different litters and individual pigs. This variation may influence the IR to infectious disease and allergens as well as to vaccination. Intervention may have the potential to favorably alter immune response capability in newborn piglets which can induce lifetime benefit in general health. This study attempts to find out if controlled prophylactic exposure of neonates to safe microbial stimuli in the form of injected heat-killed bacteria will balance the immune system response. Heat-killed E.coli or bacterial derivatives lipopolysacharide (LPS) or muramyl dipeptide (MDP) were given by intramuscular injection (im) on each of days 1-7 of life or the live probiotic Lactococcus lactis (LL) was given orally on days 1-7, 10, 12, 14, 21, 28 & 35. Pigs were then given the egg allergen ovomucoid (Ovm) to trigger the immune system. Treatment with LPS significantly reduced frequency of allergic signs while MDP increased frequency. Neither treatment altered severity of signs. There was no significant effect of E.coli treatment on frequency or severity of clinical signs of allergy. The results confirmed that all the treatments can modulate IR in newborn pigs. Treatment of newborns with LL was able to significantly induce a type 1 immune response.
A Literature Review on the Effects of Moisture Enhancement on Pork Quality
Posted in: Ontario Pork, Pork Insight Articles by admin on August 30, 2011 | No Comments
Most pork in North America undergoes some form of enhancement, either by adding extra moisture or the injection of a solution that contains sodium and phosphates before the meat is converted to roasts or chops. This process enhances meat juiciness and tenderness, although, increased sodium in processed products has recently come under scrutiny of health professionals and consumers, and grocery stores are looking into marketing non-enhanced pork. This puts more emphasis on pig nutrition as a way to enhance pork quality. A survey of pork consumers found that most preferred the texture and taste of enhanced pork, but would rather buy non-enhanced pork because of a preference for less processed food. Solutions can be added to pork to improve flavor, tenderness, juiciness, and overall consumer acceptability and pumping meat is a way to add weight which can improve retail margins. But the intake of to much sodium can lead to health risks such as high blood pressure and hyperphosphatemia and over processing meat can deter consumers as trends shift to more natural foods. Pork producers would benefit from being able to produce higher quality pork that is not dependent on enhancement to achieve consumer approval.
Stillbirth and Preweaning Mortality in Litters of Sows Induced to Farrow with Supervision Compared to Litters of Naturally Farrowing Sows with Minimal Supervision
Posted in: Ontario Pork, Pork Insight Articles by admin on August 19, 2011 | No Comments
The objective of this study was to evaluate the benefits of induced farrowing with supervision on rates of stillbirths and preweaning mortality. A total of 159 multiparous sows were assigned in approximately equal numbers to two groups. Group One sows (n = 75) were induced to farrow using two intravulvar injections of 5 mg prostaglandin F2α administered 6 hours apart on day 114 of gestation (Day 0). Farrowing was supervised, with assistance given as required. Group Two sows (n = 84) were allowed to farrow naturally, with supervision and neonatal care standard for the production facility. All live piglets were weighed at 3 days and 21 days of lactation. Of the Group One sows, 56 farrowed during working hours on Day 1. There were fewer stillbirths per litter in Group One than in Group Two sows (0.4 ± 0.09 versus 1.0 ± 0.17, respectively). There was no effect of treatment on overall preweaning mortality. Weights were greater for Group One than for Group Two piglets at both 3 days of age (1.9 ± 0.04 kg versus 1.7 ± 0.02 kg, respectively; P < .01) and 21 days of age (5.7 ± 0.06 kg versus 5.5 ± 0.05 kg, respectively;P <.01). Inducing farrowing and providing supervision on the day of farrowing can reduce stillbirths. However, reducing overall preweaning mortality requires more than 1 day of supervision.
The Metabolic Availability of Threonine in Common Feedstuffs Fed to Adult Sows Is Higher Than Published Ileal Digestibility Estimates
Posted in: Ontario Pork, Pork Insight Articles by admin on August 15, 2011 | No Comments
Amino acid (AA) requirements for sows during pregnancy are currently under review. However, requirement recommendations must be accompanied by an estimate of the bioavailability of AA from feeds to ensure adequate supply of AA and to minimize excess nitrogen excretion. Current ileal AA digestibility estimates are based on growing pig data; however, availability of AA in adult pigs may be different from that in growing pigs. The metabolic availability (MA) of threonine (Thr) in corn and barley was determined in 6 pregnant sows using the indicator AA oxidation method and L-[1-13C]phenylalanine as the tracer AA. Sows were fed reference diets formulated from 30 to 75% of the breakpoint derived in Expt. 1; all other nutrients were set at 120% of requirement. Test ingredients diets were formulated to supply Thr at 75% of the determined requirement. Tracer phenylalanine was given orally in 8 one-half–hourly meals and expired 13CO2 was quantified. The determined MA of Thr from corn and barley fed to pregnant sows was 88.0 and 89.3%, respectively. The determined MA was 7 and 9% greater than the published standard ileal digestibility estimates of Thr in corn (82%) and barley (81%), respectively. Mature animals have a greater capacity to digest and absorb nutrients from feed ingredients than previously assumed based on ileal digestibility studies. Sow diets formulated based on published ileal digestibility estimates are overformulated with respect to available protein and AA and thus increase excess nitrogen excretion and potential environmental concerns
The First Limiting Amino Acid in Late Gestation may not be Lysine
Posted in: Ontario Pork, Pork Insight Articles by admin on August 13, 2011 | No Comments
The order of first limiting AA in late gestation was determined in 14 sows (6 gilts, 8 2nd parity sows) using the AA deletion technique. A positive control (PC) diet was formulated to contain all essential AA at 160% of current recommendations (NRC 1998). Lysine, threonine, tryptophan and branchedchain AA were each removed from the PC diet to 60% of current recommendations (PC-Lys, PC-Thr, PC-Trp, PC-BCAA, respectively). Sows received each of the diets in random order. Plasma urea nitrogen, indicator AA oxidation and protein turnover (L[1-13C]phenylalanine as tracer AA) were used to evaluate the response to dietary AA deletion from 90-111 d of gestation. Data was analyzed using a Mixed model with sow as random variable. Parity was tested as a covariate but was not significant. Fasted plasma urea nitrogen (mg/dL) was highest (P < 0.09) for the PC-Lys (11.77) diet compared to the PC (8.89) diet followed by the PC-BCAA (10.81) and PCTrp (10.74) diets. Indicator AA oxidation (%) tended to be higher (P < 0.15) for the PC-Thr (18.8) and PC-Trp (18.4) diets compared to the PC (16.4) diet. Tracer flux and protein breakdown (μmol/kg body wt per h, P < 0.05) were higher on the PC-Trp (91.57 and 45.08, respectively) diet compared to the PC (73.72 and 27.97, respectively) diet. The first limiting AA in late gestation may be Thr or Trp rather than Lys but appears to be dependent on the response parameter. Changes in the order of first limiting AA in late gestation in sows means that the traditional Lys to AA ratio used in diet formulations, based on growing pig data, may not apply to pregnant sows.
Dietary Threonine Requirement for Maintenance is 98 mg/kg^0.75 in Adult Sows
Posted in: Ontario Pork, Pork Insight Articles by admin on | No Comments
The objective of this study was to determine the threonine requirement for maintenance in adult sows using the indicator oxidation technique. Four non-pregnant Hypor Hybrid (Hypor Inc) sows (233.0±18.6 kg BW) were adapted to 2.2 kg of a semi-synthetic diet containing 14.0 MJ ME/kg and 3.77 g/kg threonine. Each sow received 6 test diets, in random order, providing threonine intakes of 20, 40, 60, 100, 120 and 140 mg/kg0.75. After adaptation to each diet, indicator amino acid oxidation using L-[1-13C]-PHE was determined simultaneously with indirect calorimetry for 4 h. Plateaus in oxidation were achieved within 1.5 h. PHE oxidation decreased as threonine intake increased up 100 mg/kg0.75 BW, and did not change at greater threonine intakes. Maintenance threonine requirement, calculated by breakpoint regression analysis, was 98 mg/kg0.75. Heat production was linearly correlated (r = 0.70, P = 0.001) with PHE oxidation. Heat production responded in a quadratic manner to threonine intake, and was minimized at a threonine intake of 72 mg/kg0.75. The mean respiratory quotient (RQ, 1.067±0.011) showed that dietary energy was not limiting. RQ was greatest (P<0.001) at threonine intake of 87 mg/kg0.75. The reduced heat production and increased RQ at threonine intakes close to the requirement indicate that maximum energetic efficiency is achieved when both amino acid deficiency and excess are avoided.
Determination of Optimal True Digestible Calcium (Ca) to Phosphorus (P) Ratio in Grower-Finishing Pigs for Minimizing Phosphorus Excretion
Posted in: Ontario Pork, Pork Insight Articles by admin on August 8, 2011 | No Comments
Phosphorus is an expensive ingredient in pigs diets, despite this it is often given to pigs in excess and therefore is not digested and then spread in fields as manure. The objective of this study was to determine the effect of changes in dietary true digestible calcium (Ca) to true digestible phosphorus (P) ratio on growth performance, efficiency of P utilization and manure P excretion. The first experiment involved a small group of pigs put on one of two diets, each was based on corn and soybean meal and two levels of Ca and P with the lower nutritional diet having 25.5% corn starch. There was also a digestible marker in each diet. Pigs who were on the low nutrient diet had reduced ADG, and had a decreased feed conversion ratio. The second experiment involved six diets, which were all corn and soybean meal based but each with a different ratio of Ca and P. Some results from the second experiment were that changes in the Ca and P ratio had no effect on the average daily feed intake. Changes did have an effect on ADG and feed conversion ratio with positive responses in diets 2-4 which had ratios of 0.74-0.81:1 (Ca:P). It was concluded that changes in dietary Ca to P ratio have significant effects on growth performance. Dietary true digestible Ca to true digestible P ratio of 0.90:1 to 1.10:1 equivalent to total Ca to total P ratio of 0.70:100 to 1.20:1:00 may be optimal for feeding grower pigs.
Manure Application Technology and the Impact on Nitrogen Dynamics
Posted in: Ontario Pork, Pork Insight Articles by admin on July 21, 2011 | No Comments
This study attempted to find the agronmic value and loss of nitrogen from different application methods and timing methods of swine manure. The areas that were tested were ammonia volatilization, soil inorganic nitrogen levels, and nitrogen uptake and yield for corn. Some of the different application methods were pretilage with aerator, deep or shallow injection, surface applied with the crop in and without the crop in, different rates of nitrogen per hector as well as others methods. The timing was tested by doing experiments in late summer, fall, spring, and side dress. This study found that deep or shallow injecting resulted in virtually no ammonia volatilization, and the aerator treatment had lower emissions than the surface applied treatment. Soil inorganic N was found to be generally similar regardless of manure application method. The study found that manure application method and application timing significantly affected the amount of nitrogen lost by volatilization except under cool wet conditions in which the application method had no effect.