Original sentence: Many laboratory guinea pig strains are based on the Dunkin-Hartley English strain and are albino, although pigmented strains are also available.On 20 January 2006 Darley Oaks Farm in the United Kingdom ceased operating and therefore ceased breeding guinea pigs for scientific research and animal testing, after a 7 year campaign by the Save the Newchurch Guinea Pigs animal rights campaign.One theory is that the antibiotic actually kills off intestinal microflora that the guinea pig needs for digestion, rather than poisoning the animal itself, leaving it vulnerable to an opportunistic infection by Clostridium difficile and similar pathogens.This fact, mentioned in a well-known speech by Howard Florey, is often used as an argument against the efficacy of animal testing
Edited sentence: Many lab guinea pig strains are based on the Dunkin-Hartley English strain and are albino, although pigmented strains are also available.On 24 August 2005 Darley Oaks Farm in the UK announced that it was ceasing breeding guinea pigs for scientific research and animal testing, after a campaign by the Save the Newchurch Guinea Pigs animal rights group.The prevalent theory is that the antibiotic actually kills off intestinal microflora that the guinea pig needs for digestion, rather than poisoning the animal itself, leaving it vulnerable to an opportunistic infection by Clostridium difficile and similar pathogens.This fact, mentioned in a well-known speech by Howard Florey, is often used (usually taken out of context) as an argument against the efficacy of animal testing