• In the feed mill, formic acid is now classified as a bacterial decontaminating agent (including, but not limited to Salmonella) to improve feed hygiene (Feed Additive Register 2017/940).
  • It has also been shown to be effective against enveloped viruses such as Avian Influenza (AI) and African swine fever (ASF) (Juszkiewicz et al., 2019).
  • pHorce contains formic acid and therefore helps to control levels of potentially harmful pathogens that may be present in feed or raw materials and reduces the transmission of these to the animal.
  • pHorce is part of Anpario’s Acid Based Eubiotic (ABE) range and is a concentrated blend of pure liquid formic and propionic acids on a unique mineral carrier delivery system; chosen to ensure maximum efficacy during feed manufacture and throughout the gastrointestinal tract (GIT).
  • Recent trial work supported by Anpario has shown positive results of including pHorce in feed which was co-infected with porcine reproductive and respiratory syndrome virus (PRRSV), porcine epidemic diarrhoea virus (PEDV) and Seneca virus A (SVA).
  • Feed has been identified as a potential risk for contamination of PEDV (Dee et al., 2014) and subsequently, the risk to feed associated with other viruses has since been identified (Dee et al., 2016). Therefore, work of this nature is valuable in understanding how these risks can be mitigated.

An independent trial was conducted with Dr. Scott Dee at Pipestone Applied Research facility (Biosafety Level 2) in the USA to test the anti-viral efficacy of pHorce using their standard protocol. Treatments included a positive control (infected feed, no mitigants) and pHorce (infected feed, 6lb/ton (3kg/MT) pHorce). Pigs were selected for body weight (33lb/15kg) and originated from a naïve herd documented to be free of all 3 viral pathogens by monthly testing and clinical history. The trial was carried out over a 15-day period with 100 pigs/room (6 pens/room) and a designated feed bin/room. Viral challenge was administered on days 0 and 6 using the ‘ice block model’ whereby known volumes of SVA, PRRSV and PEDV were provided in a suitable frozen media which would melt and permeate the feed before it was augured into the designated room. Feeder samples were collected on days 0, 6 and 15 post-inoculation of the feed. Post-mortem samples were collected from 30 pigs (per room) selected for clinical illness (if apparent) 15 days post-inoculation and pigs were observed daily for clinical signs of infection. All samples were evaluated for viral presence by PCR and nucleic acid sequencing. Performance parameters; start and end body weight and mortality were also collected from all pigs and analyzed for significant difference (p<0.05) by ANOVA. Full trial method is available upon request.


Table 1. Prevalence of clinical symptoms of disease (day 15 post-inoculation).

Treatment Prevalence of Clinical Signs of Disease
pHorce 0% 0% 0%
+ve Control 100% 100% 100%


Table 2. Infection levels in post-mortem samples (day 15 post-inoculation).

Treatment Post-mortem Infection Levels
pHorce 0% 30% 0%
+ve Control 100% 100% 20%

Figure 1. Effect of treatment on average daily gain (ADG) 15 days following initial viral challenge (a,b: denote significant difference at p< 0.05). Figure 2. Effect of treatment on group mortality 15 days following initial viral challenge
  • No evidence of SVA or PRRS infection was observed in pigs consuming feed supplemented with pHorce (6lb/ton), however evidence of infection (SVA, PEDV and PRRS) and clinical signs were apparent in the positive control population.
  • No clinical signs associated with any disease were seen in pHorce supplemented pigs.
  • Pigs supplemented with pHorce exhibited a lower mortality and a significant increase in average daily gain compared to the positive control treatment.
  • pHorce has been shown to be effective in mitigating the effects of viral infection from feed.



Minimum pHorce inclusion for antiviral activity is 3kg/T