Better Pork - December 2004

Boar taint vaccine shows promise as an alternative to castration

Already in use on Australia, the vaccine is showing some improvements in productivity and offers welfare and environmental advantages. The drawback for producers: the need to vaccinate boars relatively late in their growth phase
by S. ERNEST SANFORD
For ages we have castrated male pigs to avoid consumer reaction to the unwelcome flavour of boar taint in pork. This practice, along with several other conventional activities that involve some aspect of minor surgery -- clipping of needle teeth and tail docking, for example -- is coming under increased scrutiny as an unacceptable welfare practice.

It is on a list of activities to be banned in the European Union (EU) in the near future. And, as is often the case with many welfare initiatives, we can expect similar action to follow in North America a decade or so later.

For several years now, researchers in many countries have been working to develop a vaccine that would result in the castration of boars without surgery. About five years ago, an Australian research group developed the first successful vaccine to castrate boars immunologically, loosely labelled "the boar taint vaccine." The vaccine was registered in Australia and is currently in use there.

At the 18th International Pig Veterinary Society (IPVS) Congress held in Hamburg, Germany, in June 2004, several papers were presented on various features of the boar taint vaccine.

Immunocastration works by suppressing gonadotropin releasing factor (GnRF) in the brain. As the name implies, GnRF triggers the release of gonadotropins which act on the gonads (the testicles in males; ovaries in females) to produce testosterone and androstenone in males and estrogen in females. Androstenone (produced by the testicles in the boar) and skatole (produced by bacterial interaction with contents in the hind gut) are the main culprits responsible for the offensive, off-flavour smell and taste we call "boar taint".

Surgical castration is done at a very early age, in most cases in the first week of a pig's life. This has several less than desirable consequences. For instance, surgical castrates are less efficient than intact boars at converting feed into pork, are fatter, produce more effluent and raise significant animal welfare concerns, not least among which is the pain endured by the castrate during and after castration. Furthermore, surgical wounds can become infected and unintentional self-inflicted injuries to the castrator are not uncommon.

Immunocastration using the boar taint vaccine is accomplished by vaccinating the intact boar twice, four to five weeks apart, with the second vaccination given four to eight weeks before slaughter.

The presentations at the 18th IPVS addressed the efficacy of the boar taint vaccine by measuring androstenone levels in fat samples of immunocastrated boars at slaughter, comparing growth rates and meat quality and checking for boar taint by a panel of tasters.

Consumer acceptance surveys conducted on reaction to the board taint vaccine by Australian consumers were also reported.

Compared with surgical castrates, immunocastrated (boar-taint vaccinated) pigs had:

  • Lower drip loss (less fighting stress?);

  • Slightly more pink colour;

  • Decreased carcass fat and increased lean yield;

  • Improved feed efficiency;

  • High acceptance by (blinded) consumer tasters.

In addition, scientific studies done by Swiss researchers demonstrated:

  • Androstenone levels (0.026 ug/g) in fat and testes at slaughter. These androstenone levels were well below the European Union's acceptable threshold levels (=0.5 ug/g) for boar taint.

  • Better growth rate than surgical castrates;

  • No boar taint detected by a panel of expert olfactory testers using heated salivary glands in microwave ovens, the standard testing method to detect boar taint.

There are also other attributes to be considered, including less environmental pollution, improved animal welfare, good eating quality and consumer acceptability, and creation of a "branded" pork product.

One major drawback with the boar-taint vaccine, as I see it, is the necessity to vaccinate (inject) boars at eight and four weeks pre-slaughter. Injecting large numbers of boars twice, relatively late in their growth phase, would not be a welcome task for most, especially in North America where large numbers would have to be vaccinated.

Overall, the boar taint vaccine seems to work and work well and is a new entrant into the market with many positive welfare, environmental and productivity attributes. Reports indicate that it is being used routinely in Australia to eliminate boar taint, especially for pork destined for the Asian market.BP

S. Ernest Sanford, DVM, Dip. Path., Diplomate ACVP, is a swine specialist with Boehringer Ingelheim Vetmedica (Canada) Ltd. in Burlington.

© copyright 2004 AgMedia Inc..


back














































Better Pork -December 2004

Probiotic live micro-organisms prove successful as growth promoters

by NORMAN DUNN
Using live micro-organisms as feed additives offers all-round performance boosts with swine. Such a "probiotic" feed mix, which included lactic acid and enterococci bacteria and was fed to pregnant and suckling sows in a Technical University of Munich trial, reduced sow weight loss during suckling by 7.5 per cent compared to sows on non-supplemented rations and also cut litter mortality by 19 per cent.

The same supplement fed over 16 weeks to feeding hogs increased daily liveweight gain (dlwg) by 3.4 per cent over hogs on the same diet without a live micro-organism supplement, improved feed conversion by over five per cent, and even led to 1.7 per cent more lean meat in the subsequent carcases.

The background to recent trials with these probiotic swine supplements is the growing reluctance of European Union states to allow antibiotics as growth promoters in feed. Many individual quality-control food production organizations have already completely stopped antibiotic use in feed.

Feed probiotics were discovered in the search for effective substitutes to control piglet diarrhoea and reduce subsequent mortality. Trail results from Germany are causing much interest amongst hog farmers.

Firstly, this is because the sector saw what an almost complete ban on antibiotics in feed did in Sweden where there was no alternative (massive increase in piglet diarrhea, post-weaning mortality increased by an average 1.5 per cent and five extra days needed to take piglets up to 25 kg).

Secondly, initial results with new probiotic hog feeds are indicating performances almost equal to those achieved with growth promoter antibiotic use.

The probiotic theory is that introducing more beneficial micro-organisms into the hog intestine backs up the activities of native beneficial organisms there, improves digestion and at the same time depresses activity of pathogenic gut organisms. For instance, work at the Technical University in Munich showed that a probiotic mix in piglet feed significantly increased the beneficial enterococci and lactic acid bacteria populations, while reducing E. coli presence in the gut.

At the same university, tests with a commercial probiotic additive prepared by the German Schaumann company compared two groups of sows from day 90 of pregnancy to litter weaning at day 28. The control group was on conventional feed alone and the other on the same feed but with the probiotic additive. The sows on the supplemented diet gained four kilograms more bodyweight on average before farrowing and average weight loss during suckling was 7.5 per cent lower.

The researchers reckon that piglets ingested probiotic feed given to their mother through her faeces in the farrowing pen and the result in this particular trial was that mortality to weaning was nine per cent compared with 11 per cent for the control litters. Consumption of starter feed by the young piglets whose mothers were on the probiotic diet averaged 61 grams per day and only 54 grams for the litters of non-supplemented sows.

Supplementing the same probiotic additive with feeding hogs over 16 weeks saw the hogs gaining an average 821 grams per day compared with the control group's 749grams. Feed conversion ratio and carcase lean meat content were also superior for the hogs on probiotic diets. BP



© copyright 2004AgMedia Inc..


back

































Better Pork - December 2004

What effect do starter programs have on performance?

In this experiment, designed to assess the impact of different starter programs on variability in performance, researchers found that, while Average Daily Gain was similar, feed efficiency was affected by the program used
by DENISE BEAULIEU, JOHM PATIENCE, RUURD ZIJLSTRA, and RYAN MOHR
Variability in growth and performance is a concern to pork producers because of the negative impact it can have on revenues and expenditures. Two options are available to deal with this problem. The first is to reduce variability and the second is to manage it. If variability is considered to be excessive, using management practices to reduce it is a reasonable approach.

This experiment was designed to determine the effect of a starter program on the variability in animal weights at nursery exit. Treatments consisted of four starter programs, formulated and fed according to manufacturers' specifications from weaning (day 0) to nursery exit (day 50).

The starter program has the potential to influence the relative growth of individual pigs within a group by allowing the smaller and younger pigs to excel relative to the older and larger contemporaries. Variability will be reduced if the feeding regimen allows the smaller pigs to "catch-up" or meet the performance of the larger animals in their cohort. It is recognized that the impact nursery diet has on variability is complex; but determining whether a feeding program can reduce the impact of variability was considered a first step.

A total of 560 pigs were used in this experiment, this representing all the available pigs from two consecutive weeks of weaning at PSC Research Farm near Elstow Saskatchewan. The only pigs excluded from the experiment were those suffering from an obvious medical or physical problem.

The experimental group represents a typical and complete weaning group. Animals were blocked into one of four weight groups. The treatments consisted of four commercial programs currently in use in Western Canada, which were fed according to the manufacturers' directions. The only restriction on the program was the medication -- all diets were required to include LS20 at the recommended level.

Piglets were weighed individually when they were placed on test (day 0) and on day 4, day 7, day 13, day 20, day 34 and day 50 (nursery exit). The Coefficient of variability was computed within a pen and analyzed as a variable across pens. To ensure confidentiality for the participating companies, the performance data from one company was arbitrarily assigned a value of 100, and the data from the other companies is expressed relative to this. Significance was declared at the P < 0.05 level.

Table 1. The effect of starter program on the performance of nursery pigs. The data were indexed to diet A which was arbitrarily assigned a value of 100.
Treatment
  A B C D Meana SEMa
Initial weight, kg 100.00 100.00 100.00 100.00 6.26 0.018
Final weightb, kg 100.00 100.31 104.37 101.92 32.36 0.341
ADG, kg/d 100.00 100.00 103.15 102.95 0.52 0.008
ADFIb, kg/d 100.00 99.31 105.82 105.13 0.74 0.009
FCEb 100.00 100.57 97.30 99.29 0.70 0.004
Feed cost/kg gainb 100.00 104.92 109.84 101.64 0.64 0.006
Feed cost/pigb 100.00 104.74 113.89 105.39 16.34 0.193
aCalculated from untransformed data.
b Significant effect due to treatment (Feed Conversion Efficiency) (P<0.05).

Table 2. The effect of grouping by weaning weight on the performance of nursery pigs.
Weight Group
  Lightest Light Heavy Heaviest SEM
Initial weight, kg 4.93 5.80 6.55 7.76 0.018
Final weight, kg 29.19 31.74 32.94 35.55 0.341
ADG, kg/d 0.479 0.519 0.521 0.545 0.008
ADFI, kg/d 0.665 0.730 0.756 0.800 0.009
FCEa 0.719 0.711 0.689 0.681 0.004
Feed cost/kg gain 0.64 0.63 0.64 0.64 0.006
Feed cost/piga 15.29 16.24 16.49 17.33 0.193
aSignificant effect of weight group (P<0.05).

Table 3. The effect of starter programs on the coefficient of variation (CV, %), calculated from body weighta within pens. Pigs had been blocked by weight at weaning. The data were indexed to diet A which was arbitrarily assigned a value of 100.
TREATMENT
Phase A B C D Meanb SEMb
day 4 100.00 98.77 101.97 95.08 8.05 0.42
day 7 100.00 89.81 97.98 92.04 8.94 0.65
day 20 100.00 91.37 94.34 95.21 13.13 1.16
day 34 100.00 104.43 83.14 97.59 12.39 0.84
day 50 100.00 94.13 85.43 99.36 10.33 0.68
aCalculated from pen data, averaged for each treatment. The overall CV for each nursery room averaged 17.8 per cent at day 0 and 12.6 per cent at day 50.
bCalculated from untransformed data.

Table 4. The effect of grouping by weaning weight on the coefficient of variation (CV, per cent) calculated from body weighta.
WEIGHT GROUP
Phase Lightest Light Heavy Heaviest SEM
day 4b 8.13 8.03 8.29 7.73 0.42
day 7 9.42 8.46 9.23 8.67 0.65
day 20 13.79 12.60 13.01 13.13 1.16
day 34b 12.87 13.44 10.70 12.56 0.84
day 50b 10.91 10.27 9.32 10.84 0.68
aCalculated from pen data, averaged for each weight group. The overall CV for each nursery room averaged 17.8 per cent at day 0 and 12.6 per cent at day 50. bSignificant effect due to weight group (P<0.05).

The results showed that the starter program had a modest effect on performance (Table 1). However, when examined within specific phases (data not shown), no one program outperformed the others. Nor did any starter program elicit an improvement within specific weight groups. Feed cost per pig or per kilogram of gain did differ between feeding program. Feed costs were based on information provided by the collaborating feed companies and was intended to reflect the price charged to a customer for this program.

As mentioned above, the objective of this experiment was to determine if differences exist among commercial starter programs in terms of their impact on variability at nursery exit rather than to determine the "best" commercial starter program or to examine specific nutrients which affect pig growth during the nursery phase.

Although weight group had an effect on CV at nursery exit, starter program had no effect on uniformity. Moreover, no starter program consistently improved uniformity within a specific weight group.

Within every weaning group there are some very lightweight pigs. Uniformity at nursery exit will be improved if we can specifically increase the growth rate of these pigs. The effect of starter program was not specific for any weight group, and therefore will not affect overall variability.

Overall, Average Daily Gain ADG was similar between programs. However, the Average Daily Feed Intake differed, thus feed efficiency was affected by the program used. Variability in pig growth, determined as the coefficient of variation, was not affected by starter program. This was true regardless of the starting weight of the group of pigs.

Therefore, although performance may be affected slightly by the use of a specific starter program, the change in performance is uniform across a group; and the variability in body weight at nursery exit will not be affected. The authors acknowledge with gratitude the collaboration of the participating feed companies in Western Canada. Strategic program funding is provided to the Prairie Swine Centre by Sask Pork, Alberta Pork, the Manitoba Pork Council and the Saskatchewan Agricultural Development Fund.BP



© copyright 2004AgMedia Inc..


back














































Better Pork -December 2004

Good housekeeping is the key to dealing with swine odours

But research is also underway on a variety of fronts to help producers reduce odours and respond to complaints from the public
by JIM DALRYMPLE
Pork production units, more so than any other livestock enterprise, are criticized for odours, which originate from the pigs themselves, from manure stored within the building or in separate manure storage facilities and from field application.

Environmental concerns have escalated since the Walkerton crisis, but pork producers would be under less pressure if odours could be reduced or eliminated. Many rural dwellers have little or no contact with farming operations and base their fears on opinions and not factual information.

Currently, research is underway in all pig-producing countries on methods to reduce or eliminate the odours from swine barns and, in particular, manure application. Research initiatives include covering storage units, odour control additives, separators, aerators, composters and manure injection techniques. In the future, biogas production will likely become a reality, making the larger pork farms a source of alternative energy.

Volatile compounds such as sulphides, ammonia, indoles and phenol compounds are of concern, though it is interesting that indoles, a product of protein decomposition in the intestines, produce an unpleasant smell but are used in perfumes.

But all individuals may have different perception and recognition of odours. The variability of sources causing odours, environmental factors such as humidity, hot and cold temperatures, wind velocity and direction, and individual human odour thresholds all make it very difficult to assess odour emissions and determine acceptable levels of pig-related odours.

Scientists have started to study the complex psychological reactions to the ways in which people respond to specific odours, such as those associated with pork production. A report from the United States indicates that a large high-tech swine confinement system locating in an area of traditional style pork production and farming operations can expect to have the local residents find the odour more objectionable than odours of similar intensity from a more conventional pork production unit.

Pigs themselves can be an odour source. Current building design and barn construction, slotted floors, individual pen layout, attention to appropriate stocking density, location of feeders and water sources and ventilation have resulted in cleaner pigs. Dirty pigs can be a particular problem both because of the additional surface area of the pigs, covered by their manure and because the animal's body is a warm surface.

The pork industry recognizes the general public's concern regarding swine manure odours and the methods being researched are many and varied:

  • University of Guelph research scientists are assessing the electrochemical oxidation of the odourous components in the aqueous phase of settled hog manure, which could then be sprayed on land in its "deodorized form."

  • Also at Guelph, biofiltration is being researched. Biofiltration is a process whereby contaminated air is cleaned by pulling it through a matrix of organic material.

  • At many locations in Canada and the United States, possible feed additives to help eliminate odours are being studied. Preliminary studies have suggested that dietary supplements of non-starch polysaccharides may be effective in decreasing total ammonia and sulfide production and emission from manure.

  • A National Pork Producer Council study tested the effectiveness of 35 commercial products in odour control using a machine called an olfactometer. A number of the products did produce significant ammonia and hydrogen sulphide reductions. The effectiveness can depend on many factors including temperature, bacterial population of the manure, frequency of pumping, and level of solid buildup in the storage unit.

  • Research at the Prairie Swine Centre Saskatoon is looking into methods of reducing dust levels. Dust can carry gases and odours and originates from feed, bedding materials, manure and the pigs themselves. Using best management practices to reduce the dust in and around barns will reduce odour levels.

  • Several research locations are developing electronic sensors that might have the potential for more objective odour intensity measurement.

As researchers continue to search for the means to reduce odours, producers have several opportunities to improve their own operations.

  1. Good housekeeping is a key to odour abatement.

  2. Keep surfaces dry and clean as possible.

  3. Assess the effectiveness of additives under your own specific conditions.

  4. Covering manure storage units is helpful.

  5. Diet modification is effective, as is ensuring that protein and amino acid levels are fed close to requirements for all ages of pigs.

  6. Landscaping, including windbreaks, is helpful.

  7. Proper land application, manure injection and attention to weather conditions during spreading are important. Be aware of wind conditions and location of sensitive neighbors. Inject and incorporate as soon as possible.

The elimination of farm odours would go a long way in reducing the environmental misconceptions that exist related to modern high-tech swine units. BP



© copyright 2004AgMedia Inc..


back














































Better Pork -December 2004

The multiple benefits biotechnology holds for pork production

by JIM DALRYMPLE
Biotechnology, biodiversity and bioproductivity are all terms being tossed about in agriculture and pork production circles these days.

In the pork industry, biotechnology is being used to improve production efficiency, enhance pork quality, increase disease resistance and sustain the environment for future generations.

Biotechnology is the application of science and engineering in the direct or indirect use of living organisms or parts or products of living organisms in their natural or modified form. This definition encompasses organisms developed through traditional breeding methods and newer technologies such as genetic engineering.

Reproductive technologies. This is the area of biotechnology most widely used in pig production. Artificial insemination, using liquid and frozen semen, embryo transfer and embryo manipulation, has benefited the industry through genetic improvement and disease prevention. Furthermore, the fact that several thousand fewer boars are needed means less feed and water used, less waste produced, less problems with marketing, both from the standpoint of animal welfare and pork quality, and likely fewer injuries on Ontario farms.

The Canadian Food Inspection Agency (CFIA) and Agriculture and Agri-Food Canada, with the input of other federal departments and the pork industry, have been assessing any animal health risks and food safety risks that may occur from emerging technologies.

Transgenics. Transgenics is the introduction of genetic material from one organism into another. More than 70 studies have been conducted recently on transgenic pigs, most of them falling into one of four categories -- generation of transgenic pigs as potential organ donors for humans; transgenic pigs as bioreactors for production of therapeutic proteins in milk; transgenic pigs that improve growth rate and efficiency; and transgenic modified pigs that improve disease resistance.

Modern science is conducting research on zenotransplants of pig organs into human recipients. Organ rejection problems are being addressed, and these transplants could have a significant impact on health costs in the future.

Cloning. Cloning is the production of offspring that are genetically identical to the single parent organism and has implications both for human health and agriculture. As with traditional breeding methods, genetically superior animals can be selected by cloning, offering the opportunity to produce exact copies without diluting the desired genetic traits.

Genomics. Many new technologies in genomics -- the study of DNA sequence, structure and function -- make it possible to identify genes, their effects, and either enhance or suppress their expression. Gene research, for example, is attempting to isolate the gene related to influenza virus infection. These and other studies on diseases are very beneficial to both producers and consumers. Work is also underway on "immunocrastration,' the development of a vaccine to eliminate the need for surgical castration.

The Animal Biotechnology Unit (ABU) of the CFIA's Animal Health and Production Division is responsible for establishing animal health standards and augmenting regulatory controls for the development of biotechnology-derived animals. Its mandate is to evaluate the reproductive technologies used in livestock production with a focus on animal health and welfare. It also works with other government agencies to develop and implement risk-based regulatory controls for the assessment and control of biotechnology-derived animals. Consultations with all segments of agriculture and the general public have been underway for several years.

Through the years, pigs have provided more than just food. Nearly 40 pharmaceuticals and other products benefiting human health are derived from porcine tissues, including hormones, enzymes, heart valves and skin. "Pharming" of pigs will continue due to their similarities to humans. The need for organ transplants will escalate, as will the need for sources other than human donors.

Work on the "Enviropig,' a pig requiring less phosphorus in the diet, is continuing in Ontario. This pig will enable the pork industry to reduce the amount of phosphates in feeds, reduce the amount of phosphates excreted in manure, give the industry the opportunity to export significant numbers of breeding stock and lead to less environmental concerns from pork production.

Science is making enormous strides in adding to our understanding of the pig, its value and quality as a food source and in new product development.

Biotechnology continues to offer new genetic technologies for improving pork production and disease resistance, as well as new technologies that can benefit human health and the environment. BP



© copyright 2004AgMedia Inc..


back