The economic and environmental impacts of removing ionophore coccidiostats from the UK broiler sector.

Ionophore coccidiostats are widely used in the UK broiler sector at present but their future use has been questioned. A review of published and technical literature has been undertaken to assess the likely impacts of removing ionophore coccidiostats from UK broiler production. Expert opinion from two poultry veterinarians has been used to establish the probable approach and interventions that would be needed in a 'no-ionophore' programme and the likely impacts. Comparisons have been made between 'standard' and 'no-ionophore' programmes, covering farm production costs and environmental impacts. Key performance assumptions for the 'no-ionophore' programme include one extra day of growing time to achieve target average liveweight of 2.26 kg and a five point increase in feed conversion ratio (FCR) from 1.58 to 1.63. Any increase in mortality is considered marginal if other interventions are adopted and therefore this study has assumed no differences. Veterinary opinion considers that a reduction in stocking density of 4 kg of liveweight per square metre would be needed to maintain good health in a 'no-ionophore' programme; a 2-day increase in house turnaround time between flocks is also recommended. Changes to feed specifications would be expected, together with the use of a coccidiosis vaccine. Based on stated assumptions, farm production costs are calculated to be 5.7% higher for the 'no-ionophore' programme than a standard programme. Optimistic and pessimistic scenarios indicate cost increases ranging between 3.3% and 10.8%. The 'no-ionophore' programme was also found to result in a 3.9% increase in greenhouse gas emissions per bird and to require 3.3% more land to grow crops for poultry feed. Increased production cycle length and reduced stocking density in the 'no-ionophore' programme would mean that a 19% increase in UK broiler growing space is required, to maintain current chicken meat output levels. [ABSTRACT FROM AUTHOR]