The larger of our two herds is home to 1,050 sows, which includes our grandparent (GP) herd of about 200 Landrace.
These Landrace GPs should produce 70 selectable cross-bred gilts each time a batch farrows. The progeny from the GPs are then raised on farm and used as replacement breeding females at both farms.
All the Landrace GPs are roughly the same parity, and when they start to reach fifth parity, we cull them out and start again.
Group sizes are too low to produce enough replacement gilts and a fresh intake of GP Landrace gilts is required.
Typically, we get seven batches of 30 and they arrive with a spread of ages, so that after some additional rearing, we can integrate them with the main herd.
Mating is performed by artificial insemination using Duroc semen.
Landrace GPs have historically much higher return rates at service and higher drop-out rates (failed to breed) than our homebred sows and gilts.
This is the main reason the original 30 strong group sizes drop so much. The Landrace breed is simply not as robust or hardy as the Duroc crossbred breeding stock.
At least that was the case until our latest arrivals. They have reached maturity and conceived better than ever before.
Four of our batches have now been pregnancy tested and the conception rate is 94%. Out of the first batch, just two gilts ended up as a 21-day return and two dropped out after failing to breed, giving a tidy 87% farrowing rate.
The only disappointment has been their performance in the farrowing paddocks.
After a bit of number crunching, I can see our homebred gilts are producing a healthy average of 13 piglets born alive with 0.5 born dead and a 9.5% mortality figure. The new GPs have only managed 10 born alive with 0.3 born dead and 8.5% mortality to date.
The 10 born alive is woefully poor, I only hope it’s just one of those never-to-be-explained one-offs.
It’s such a disappointment for everyone involved, especially when everything else had been looking so good. Batch two is farrowing – I’m crossing everything for better litter sizes.
Rob manages an outdoor pig operation in north Norfolk. See his biography.