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Pig Focus
Pig genetics have made some tremendous performance
advances over the last 30 years but has it come at a
cost to the fitness of the modern pig. There are several
di erent genetic technologies that have been used
to improve trait performance for pig farmers. Some
examples would include: Terminal Cross Mating system,
Optimal Genetic System Structure, BLUP based selection
programs; Marker Assisted Selection; Mate-Select
Software; Genomic information. It is now possible for
the commercial pork producer to reap the benefits
from all the above genetic technologies, either directly
using them, or having their genetic supplier use them.
These technologies have helped to achieve huge
improvements in performance of key swine traits. Over
the past 30 years we have seen:
1. Born alive per litter has increased from 10 to plus 14.
2. Backfat has decreased from 25mm to less than
3. Lean meat has increased from 45 per cent to plus 57
per cent.
4. Growth rate has increased from 100kg pig @ 30 wks
to 130kg pig @ 26 wks.
5. Feed conversion (weaning to sale?) has improved
from 3.5:1 to less than 2.5:1.
However, while these are overall positive change, we
have to be aware of possible `trade-o s' for genetic
improvements. Pearson (1903) and Robertson (1967)
believed that "...individuals with intermediate trait values
have higher fitness..", and, "..extreme phenotypes cause
reduced fitness". An example of `extreme phenotypes'
causing `reduced fitness' is larger litters. As litter size
has increased in the last decades it has exceeded the
sow's uterine capacity therefore birth weight has gone
down, while pre and post-wean mortality has increased
The effect of genetic
improvements on fitness traits
The recent Teagasc Pig Conference saw Dr. John Mabry, Professor Emeritus, Iowa State University,
deliver a paper on the e ect of genetic improvements on fitness traits. Here, we o er some extracts
from his presentation.
Gerard McCutcheon, Teagasc;
Dr. John Mabry, Professor
Emeritus, Iowa State University;
Ciarán Carroll, Dr. Peadar Lawlor
& Dr. Maria Costa, Teagasc
pictured at the recent Teagasc
Pig Farmers' Conference 2019.
Pig Focus