Using higher quality boars is helping a Yorkshire farmer increase the slaughterweight of his finishing pigs by over 17 per cent while maintaining grading, thus improving returns without expanding his herd.Stephen Till, who runs a 100-sow breeding-and-finishing unit at Welburn, York, started using ACMC’s Ultra boars, through both AI and natural service, just over a year ago. The average deadweight of his finishing pigs, sent to Karro Food Group’s abattoir at Malton, was 68 kg deadweight and is now 80kg with 75 per cent of the pigs still achieving under the 12mm probe measurement specified in the contract for top grade. The aim is to push this up to 85 kg in the near future.However, he aims to improve that still further by changing the diet formulation during the latter stages of finishing, between 80 kg and 110 kg. “The current ration is ‘too good’ for the pigs above 80 kg liveweight so we are making a change to a lower protein/ lower energy diet. This combined with the use of Ultra boars and AI should improve grading still further and reduce the cost of production during the final stages,” said Stephen.He reckons that each increase of 1 kg deadweight provides extra revenue of £1.65, while the extra feed cost is around 90p per kg and other fixed costs add a further 40p per kg. “As a rough guide, at current feed costs, I reckon a 10 kg deadweight increase — which is our eventual aim — should give an increased return of around £3 per pig.”Producing heavier pigs has put some pressure on housing space, but a flexible straw-based system has enabled him to increase stocking rates in some pens. Weaners go into outside arks and run at four weeks and existing buildings are being altered to make extra pens.“As we intend to become members of the Freedom Foods assurance scheme and we can see slaughter weights increasing still further, in future we realise we will need to construct extra buildings,” he added.