As the market for pork becomes more and more differentiated, retailers and processors are looking for opportunities to meet the demand from consumers for products which meet their aspirations in terms of welfare, food safety and the environment.  This trend is well-developed in Europe where there is a wide range of pork categories such as outdoor reared, antibiotic free and organic.  Now antibiotic-free pork production is increasing significantly in the USA.  The question for producers is whether any loss in production efficiency and the additional costs involved are offset by the price premium received. European experience suggests that the additional cost per pig is in the region of $5.24.  However, a paper presented at the recent American Association of Swine Veterinarians by Darwin Kohler, James Schneider, and Chad Bierman demonstrated that removal of antibiotics on one farm did not lead to a significant loss of performance.

“The use of antibiotics in livestock feeds is meeting with increasing opposition,” note the authors. “The controversy revolves around the level of antibiotic fed to livestock for non-therapeutic use, which in turn causes an increase in bacterial resistance in humans and known allergic reactions or toxicity.”  The consumers of meat products today are asking for a more ‘natural’ food product.

European opposition has been stronger than in the US.  A ban of over-the-counter antibiotics was implemented in Sweden in 1986, Norway in 1992, Finland in 1996, Denmark in 1998, and Poland and Switzerland in 1999.  Current EU regulations state that antimicrobials used in either human or in veterinary therapeutic medicine are prohibited from use as feed-additive growth promoters in livestock.

Based on experience in Sweden and expert opinions, the likely performance effects of removing antibiotics and the cost implications are shown in Table 1.

Table 1: Technical assumptions of antibiotic ban

Trait                                        Most likely change

PSY                                         Decreased 1 pig

Weaning age                             Increased 1 week

Wean to 25kg                          Increased 5 days

FCR 25-114kg                                    Increased 1.5%

Pre-wean mortality                   Increased 1.5%

Grow/finish mortality                 Increased 0.49%

Net additives cost                     Increased $0.25/pig

Total cost/pig                            Increased $5.24/pig

Today, one form of antibiotic free (ABF) pork production is beginning to be used in the United States, note the authors.  It is based on no birth-to-market antibiotic use of any kind, no growth promotants, no natural or artificial hormones, no ionophores, no animal proteins and no animal by-products. “Can antibiotic free (ABF) pork production be more successful in the United States than indicated in Table 1?” they ask.

Case study farm shows little effect on performance

The case study reported in the paper is a 1,000-sow farrow to finish conventional confinement system.  This system has been closed to live animal introduction since 1996.  Management was interested in pursuing ABF pork production.  Small amounts of antibiotic had been used or needed in their herd, and a premium was being offered for antibiotic free pork.  Pigs are vaccinated for Mycoplasma hyopneumoniae and the herd is PRRS stable.  Gilts are raised internally and there is an off-site boar stud.  Since December 2004 no antibiotics, growth promotants, or animal by-products have been used in pigs from birth to market.  The farm maintains records of inoculations, illnesses and injuries, treatments, etc.  Very few pigs require treatment.  If prohibited medication is used in treatment, the pigs are marked for identification and are sent to conventional markets.  “Products such as zinc, copper, probiotics, enzymes, botanicals, enzymes, mannan oligosaccharides, egg antibodies, oil of oregano, and organic acids are allowed to be used in place of antibiotics in the ABF program,” explain the authors.  “However, these products are not necessary in this herd and are not in use as replacements for antibiotics.”

Table 2 shows the sow herd performance before and after ABF.  The ABF program does allow for antibiotic usage in the sow herd.  Antibiotic usage in the sow herd changed little over the six-year period.  Comparisons of traits between the ‘before ABF’ and ‘after ABF’ periods are both positive and negative and show no consistent advantage to the use of antibiotics.  Pigs had received an antibiotic at birth before ABF.  The expectation would be an increase in pre-weaning mortality. An increase from 8.2% to 9.9% did occur but was not reflected in pigs weaned per mated female per year.  Adjusted 21-day litter weaning weight is 13 pounds (5.9kg) heavier after ABF with an increase in pounds weaned per sow per year of 8%.  Only pre-weaning mortality was in agreement with the negative predictions shown in Table 1.

Table 2: Sow herd performance before and after ABF production

                                                            Before ABF                After ABF

                                                            Jul 02 – Dec 04                      Jan 05 – Jun 07

Average total pigs/litter                  11.4                             11.4

Average pigs born alive /litter                     10.4                             10.6

Pre-wean mortality (%)                   8.2                               9.9

Average age at weaning                            18.2                             20.5

Farrowing rate                                            93                               91.6

Litters/mated female/year                           2.56                             2.52

Pig wnd/mated female/year                        23.8                             23.8

Table 3 shows the herd’s finishing performance before and after ABF. Although previous reports show poorer performance with ABF production, few differences are noted here.  Only feed conversion showed a noticeable drop in performance.

Table 3: Finishing performance before and after ABF

Grow finish trait                                             2002 – 2004                2005 – 2007

Av. Lwt. of pigs entered (kg)                                18.2                             21.1

Av. Lwt of pigs sold (kg)                                      114.5                           118.4

Av. days to market                                               114.6                           115.2

Av. daily feed intake (kg/day)                    2.22                             2.36

Av. daily gain (g/day)                                            839                              839

Feed conversion ratio                                           2.65                             2.69*

*Feed conversion adjusted to common entry and sale weight

The only significant difference is in FCR and the authors calculated this to add $0.68 to production cost.  Finisher death loss was slightly higher after ABF resulting in a cost increase of $0.07 per market hog.  Average drug cost before ABF of $0.18 per market hog resulted in a saving after ABF.  Pigs were no longer sold grade and yield during the last three years therefore carcass yield and percent lean were assumed to be unchanged.

ABF premium gives bigger margins

Additional ABF premium was calculated as the difference received in harvest price by this herd versus other similar herds and selling grade and yield to the same market that this herd had been selling to before ABF.  Using this method, the additional ABF premium was estimated to be $4.26 per head in 2005 and 2006.  “The ABF premium tends to inversely fluctuate with the base grade and yield price and is much higher today when market prices are lower than in the previous two years, note the authors.  “Current additional ABF premium for November 2007 is $16.62 per head.”   Overall, taking the differences in performance and costs into account, there was a net average benefit of $7.89 for ABF production compared to the period when antibiotics were used.

Little or no differences in production numbers were observed on this farm.  The increase in cost of production has been shown to be $0.32 per head.  “Success is attributed to the use of appropriate genetics, maintaining a closed herd and maintaining a high level of biosecurity to keep pathogens out,” say the authors.  “Good management in areas of proper husbandry, nutrition management, environmental control, prompt treatment or removal of sick pigs and attention to detail is essential.”  Not only does this case study illustrate the feasibility of ABF production, but it demonstrates significant profit potential in today’s niche markets, they conclude.