It’s been a while since I mentioned our new criss-cross breeding system. We started serving our top-performing Large White cross Landrace “supersows” with Topigs Norsvin Large White back in December 2019.
We have finally farrowed the first replacement gilts from that cross (which had been served to terminal sire). The gilts produced an average of 14.76 born alive, with five of the 17 gilts farrowing more than 17. The total born averaged 15.41.
Our herd data software, PigVision, tells me that during the period March 2020 to February 2021, our gilts (all genetics and served with a few different sires) averaged 13.62 born alive, and 14.04 in total.
During that same period, we had 19 pure Landrace gilts farrow (our original grandparent nucleus herd). All had been served to a terminal sire (JSR 400) and they produced 14.11 alive and 14.57 total.
The data isn’t entirely comparable, because of the different sire lines used, but it is promising and, at the very least, competitive.
When we have weaned these gilts we will serve the best of them to Topigs Norsvin Landrace.
We are still struggling with our ex-gilts coming into heat for their parity-two service. I am keen to see what happens with the first of our new replacements.
I suspect a lot of it is to do with our gilt-rearing, which we are still trying to fine-tune to hit the optimum of 160kg at around 240 days, with an average daily liveweight gain of 600-750g at point of service.
We have already switched to using two specialist gilt diets during rearing from 50kg, but it is recommended to use three diets and start as early as 25kg.
This is to ensure longevity (bone development), prevent excessive growth rates, and to ensure reproductive performance and milk production. It is something I will definitely look into.
We are also tweaking levels of gilt finisher in our faster-growing gilts and introducing a flush feed 10-14 days pre-service.
We’ve been fastidious about weighing our gilts during rearing and are beginning to build up some good data sets from which to work.
Sophie Hope is a Farmer Focus writer from near Cheltenham. Read her biography