Angiogenic DC-SIGN+ cells are present at the attachment sites of epitheliochorial placentae

Posted in: Ontario Pork, Pork Insight Articles, Production by admin on September 15, 2009 | No Comments

Spontaneous early and mid-gestation fetal losses occur in swine. At both stages, endometrial lymphocytes associated with smaller, paler conceptuses have fewer pro-angiogenic and more pro-inflammatory cytokine transcripts compared with robust conceptuses. We hypothesized that similar differences occur in conceptus-associated dendritic cells (DCs). Using laser capturemicrodissection, dendritic cell-specific intercellular adhesion molecule-grabbing non-integrin (DC-SIGN)+ cells were isolated from attachment sites of healthy and arresting conceptuses at gestation day (gd)20 and 50. DC-SIGN+ cells were screened using real-time PCR for vascular endothelial cell growth factor (Vegf), its receptors, semaphorins (Sema) and plexins (Plxn), and for toll-like receptor (Tlr) transcripts to address potential activation pathways. Homogenized endometrial and trophoblast biopsies were quantified for type 1/type 2 cytokine transcripts/proteins. DC-SIGN+ cells from healthy and arresting conceptuses had more Vegf transcripts at early than mid gestation whereas transcripts for Vegfr1 and Vegfr2 were stable. In gd20 arresting site DC-SIGN+ cells, Neuropilin-2 transcripts were elevated, whereas at gd50 arresting sites, Plxn-A2 increased and Sema3A transcripts were lost. Tlr-1, Tlr-4 and Tlr-6 transcript abundance was independent of conceptus health. At gd20, type 1 cytokines were prevalent, whereas at gd50 type 2 cytokines predominated in endometrium and trophoblast. Thus, gestational features, characteristic of haemochorial placentation, are present in species with distinctly different placentation.

Applying New Research to Reduce Sow Feed Costs

Posted in: Pork Insight Articles, Production by admin on August 2, 2009 | No Comments

There is potential to significantly reduce the cost of sow feeding, however, current nutrient recommendations need improvement. Phase feeding, using separate diets for early/mid gestation and late gestation, may save up to $5.00 per sow per gestation. Using a single diet for gestation, but phase feeding at a higher level in late gestation, may save up to $3.00 per sow per gestation. During late gestation and lactation, addition of free amino acids can reduce feed cost. These improvements may also increase sow productivity and increase sow longevity.

Introduction

Nutrition of sows has received little attention compared to growing-finishing pigs, despite the fact that sows consume approximately 20% of the all the feed consumed in pork production. Therefore, improving sow nutrition offers the opportunity for substantial savings in feed cost. This paper will review recent research, discuss future opportunities in sow nutrition, suggest new feeding strategies for sows, and estimate their impact on feed cost.

Conclusion

There is a great deal more to be learned about energy and amino acid requirements during different phases of gestation and lactation. As this information becomes available, we expect to further reduce the cost of sow feeding while maintaining or increasing sow productivity and longevity.

Generation of epidermal growth factor–expressing Lactococcus lactis and its enhancement on intestinal development and growth of early-weaned mice

Posted in: Nutrition, Ontario Pork, Pork Insight Articles, Production by admin on July 29, 2009 | No Comments

Epidermal growth factor (EGF) plays an important role in intestinal proliferation and differentiation. Previous studies
by others have shown that administration of EGF into the ileum lumen enhances intestinal development. Objective: The objective was to examine the feasibility of expressing and delivering EGF via Lactococcus lactis to earlyweaned mice to enhance intestinal development at this critical transition stage. Design: EGF-expressing L. lactis (EGF-LL) was generated with a recombinant approach. Early-weaned mice were orally gavaged with the recombinant bacteria. Body weight, mean villous height, and crypt depth in the intestine were measured to examine the influence of EGF-LL on the intestinal development of early-weaned mice in vivo. Populations of EGF-LL were shown to survive throughout the intestinal tract, and the recombinant EGF protein was also detected in intestinal contents. Weight gain was significantly greater in mice that received EGF-LL than in control mice fed phosphatebuffered saline or L. lactis transformed with the empty vector backbone but was comparable with that of the positive control mice that received recombinant human EGF. EGF-LL increased mean villous height and crypt depth in the intestine. Immunohistochemistry also confirmed that enterocyte proliferation was enhanced in mice that received EGF-LL, as evidenced by the greater number of cells stained with proliferative cell nuclear antigen in the intestine. This study showed that EGF-LL had beneficial effects on the intestinal growth of newly weaned mice. The combination of growth factor delivery and a probiotic approach may offer possibilities for formulating dietary supplements for children during their weaning transition stage.

Designing Field Trials to Compare Vaccines or Antibiotics

Posted in: Pork Insight Articles, Production by admin on April 1, 2009 | No Comments

In-barn field trials for new vaccines or antimicrobials are useful for gauging whether the product is worth a full-scale implementation. To accurate test the product, pigs (or pens of pigs) should be randomly assigned, sufficient numbers should be used, and preferably it should be a blind trial. When running a trial having control pigs is extremely important, as there can often be wide variation in performance between pigs or groups of pigs. To improve experimental units, more pens of smaller groups can be used, and if a pig is the unit spill-over effect and the effect of the pen must be monitored. Selection bias needs to be avoided by randomly assigning pigs to a pen, and pens to a trial. As well, pig days should be used to analyze data, and any mortalities recorded.

Willowgrove Hill – an Ontario Success Story

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Willowgrove Hill is a farrow to finish facility that changed to niche marketing in 2006 after repopulating, changing genetics, changing to a closed 3 site loop, and enhancing biosecurity. Their products are omega 3 and selenium enriched, and raised without antibiotics. Marketing began with designing a website, developing pricing, and making contacts to sell the products. After starting in a small butcher shop, Willowgrove Hill was able to sell to an executive chef, then at a trade show, and then grocers. Point of Sale packaging and labeling had to be developed, and new pricing decided on. Other challenges occurred finding processors, and using federal kill plants. Overall, niche marketing takes a lot of work, contacts, marketing, and passion.

Alternative Value Chains: Jones Feed Mills Case Study

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In the Breton Family development of niche market products, Jones Feed Mills partnered with the duBreton for a 3 site production that is Certified Humane®. The Certified Humane® program feeds wholesome, nutritious feed with no mammalian protein, antibiotics, or growth promoters, and feeders must allow easy access to feed. Average weaning age must by 28 days or more, and creep feed needs to be supplied from day 10 on. Water must be clean and accessible, building specifications need to be recorded, and a comfortable lying space must be provided. Specific space allowances need to be followed, pigs must have freedom of movement, and confinement is only allowed under certain circumstances. Traditional farrowing crates are not allowed, sows must be given nesting material, and sows must be kept in the farrowing area for 28 days after farrowing. Environmental enrichment must be given, isolation is only allowed for quarantine/treatment, and abnormal behaviours (ex. tail biting) should be documented and steps taken to eliminate the behaviour. Finally, units must have an Animal Health Plan, sick animals need to be treated, and the only physical alterations allowed are needle teeth clipping, castration before 7 days, and boar tusk trimming. Ear notching and routine tail docking are not allowed.

Practical Management to the Transition to Batch Farrowing

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Aarden Farms transitioned to batch farrowing in 2007, and they give their experience with the transition. Some of the positives of batch farrowing are that a large group of pigs will become available at one time, breeding is more efficient, farrowing sows receive more attention, and specialized labourers can be trained and/or shared with other farms. The challenges include introducing gilts into the herd, repeats or open sows, hormone costs, and space limitations.

Hormonal Control of Pig Reproduction

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Synchronizing estrus in gilts and sows increases breeding scheduling efficiency and predictability, and can be achieved by using hormonal control products. During estrus, gonadotropin releasing hormone (GnRH) triggers the release of gonadotropins (FSH and LH), then ovary follicles grow and release estrogen, which results in estrus behaviours and increased GnRH. The GnRH then increases LH, and ova are released (ovulation). The eggs form a corpus luteum, which releases progesterone that inhibits FSH and LH. If fertilization does not occur, prostaglandin-F2α will be released, the corpus luteum regresses, and the estrus cycle begins again. PG 600 is made of equine and human chorionic gonadotropins (eCG and hCG) and triggers estrus cycling through its effect on FSH and LH. ECG can also be used alone to induce estrus through FSH, and GnRH or porcine luteinizing hormone (pLH) can be used to synchronize ovulation through their effect on LH. PGF2α can be used to synchronize estus, abort early pregnancies, or induce farrowing. Altrenogest is a progestin which suppresses gonadotropins, this allows for synchronization of estrus if fed until 5 days before the desired breeding dates.

Effective Ventilation

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Ammonia from manure and moisture from swine respiration can combine to reduce air quality and increases odor when a room is not sufficiently ventilated. As pigs increase in size the moisture they contribute to the air will increase, so ventilation should be increased as well. Keeping the humidity below 70% and the ammonia below 20 ppm can result in heat loss during winter months, and the ventilation rate may not maintain air quality if it is based on temperature. An alternate heat source should be used in winter months to provide heat while the ventilation is used for air quality. Two of the most common problems with ventilation are not ventilating to control humidity and not using a heater. Heat exchangers or passive solar energy collectors are two options to provide heat while saving money.

Nursery Improvement – Practical Tips

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Typically creep feeding is useful when the litter size is larger or weaning age is later, but younger weaned pigs may be able to benefit from creep feeding as well. As the number of pigs consuming creep feed increases, the post-weaning feed intake also improves. In one study, pigs that consumer creep had 0.4kg increase in post-weaning gain, so improving the number of pigs consuming creep can help improve performance. Pigs can be encouraged to eat creep feed by introducing it earlier, and using highly digestible feed to improve gain. The increased pre-weaning weight can result in a cost benefit ratio of 3:1 to 9:1. Often a walk through by a specialist can also help identify areas in which the nursery feeding management can be improved.