Previous research suggested that higher stocking rates had negative impacts on the growth rates of indoor herds.

But researchers have discovered that increasing the number of pigs in a pen does not negatively impact animals, and that increasing stocking rates would enable farms to become more profitable.

In a study on a commercial pig unit, researchers at JMW Farms in Armagh, Northern Ireland, separated entire males and female into four different stocking densities.

The densities ranged from a maximum of 0.8m2 per pig, to 0.69m2 - the smallest area allowed under welfare guidelines.

Pigs were brought in at 38kg and fed ad lib grower diets to 70kg. They were then switched to finisher diets when they reached 120kg.

The animals were weighed every two weeks, and feed intakes were recorded in each pen, enabling scientists from Ireland’s Agri-Food and Biosciences Institute (AFBI) to calculate daily gain, feed intake and feed conversion.

“The results showed there was no statistical difference across all four stocking densities,” said Michael Connery of JMW Farms.

“Final weights across all of there groups were 125-126kg, while average daily gain was just over 100g.

“There was also no difference to animal welfare across the density, showing farmers can stock pigs at higher rates without impacting on performance.

“A higher rate means more weight gained per pen, making the operation more viable."

Mr Connery said earlier studies suggesting higher numbers should be avoided might have been affected by genetics, male castration, or health issues within the herds.

“Previous trials had between five and 15 trials in a pen, while ours had 46,” he added. “More pigs in a pen leads to a more complex social structure and feeding regime.

“In our trial timid piglets had enough space to escape, so that by the time they were larger and space became more of an issue, a hierarchy had been established.”

Taken from: ‘Comparing four different stocking densities on growth rate and feed efficient of finishing pigs’ by M Connery, R W Henry and R M Wregor, presented at the BSAS Annual Conference 2018