Rex Walters

Traits of high or moderate heritability are easily improved by testing and selection. However, for traits of low heritability, improvements come from exploiting heterosis and by the use of BLUP.

Benefits and risks of heterosis and inbreeding in pig production.

Does the complexity and expense of genomics mean that it will only be available to the major global pig breeding companies in the future? If the price of genotyping continues to reduce, it may be possible for medium and smaller size breeding companies to share funding and identify desired genotypes.

One of the greatest long-term potentials for genomic selection is to identify specific genes or genomic regions with a significant impact on pig health and to aid selection for disease resistance and/or disease tolerance.

The key benefits from the use of DNA information are a greater overall genetic progress, improved selection for ‘difficult’ traits such as piglet survival and ...

Teams from 54 research groups, led by the Universities of Edinburgh (UK), Illinois (USA), Uppsala (Sweden) and Wageningen (Netherlands) have sequenced the entire genome of the pig.

The most relevant genetic defects of the skin are epitheliogenesis imperfecta, pitryisis rosea and malignant melanoma. Recent data suggest an increase of the melanoma incidence in Duroc bred, incidences of 2.60% and 0.62% have been found in two Duroc nucleus herds.

Hernias are the most common genetic defect and often cause welfare problems as well as economic loss.

The standard database for inherited traits and disorders in animal species (OMIA) lists 29 single-locus disorders, nine of these have been characterized at the molecular level, meaning that DNA testing may be used for control.

An economic model was developed that assessed financial loss through the pyramid from nucleus to multiplier to commercial herd on a per litter basis for traits with an incidence higher than 0.10%.

A survey was undertaken in a large anonymous European Breeding Company over a four year period ending March 2010. In total, 175843 pigs born were evaluated to establish the incidence of congenital defects and additional assessments were made at 95kg. More than half the total defects were identified in the growing and fattening period rather than at birth.

There is sufficient genetic variation in host response to infection to allow future breeding goals for enhanced resistance or tolerance so that there are grounds to believe that it may be possible to breed commercial animals that have increased genetic resistance or tolerance to the disease.

Anecdotal evidence from pig producers and veterinarians in the field suggests that there are genotype differences in susceptibility to PCVAD

The performance and conformation of the pig (the phenotype) depend on the combined effects of its genetic make-up (the genotype), which is mostly fixed at conception, and the environment, which includes health, nutrition, management, housing and climate.