SWITCHING to higher-quality boars has helped a Yorkshire farmer increase the slaughterweight of his finishing pigs by more than 17 per cent, while maintaining grading.

Stephen Till runs a 100-sow breeding-and-finishing unit at Welburn, York, and has improved returns without expanding the herd.

He began using Driffield-based ACMC’s Ultra boars, through 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 68kg deadweight.

That has risen to 80kg with 75 per cent of the pigs still being under the 12mm probe measurement specified in the contract for top grade.

The aim is to push this up to 85kg in the near future.

However, he aims to improve that still further by changing the diet formulation during the latter stages of finishing, between 80kg and 110kg.

Mr Till said: “The current ration is too good for the pigs above 80kg 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.”

He reckons that each increase of 1kg deadweight provides an extra 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 10kg deadweight increase – which is our eventual aim – should give an increased return of about £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 of his pens.

Weaners go into outside arks and run at four weeks. Existing buildings are being altered to make extra pens.

Mr Till said: “As we intend to become members of the Freedom Foods assurance scheme and we can see slaughter weights increasing further, in future we realise we will need to construct extra buildings.”