Genesus Global Market Report, Breed-specific weight adjustments for growth, backfat and loin muscle depth

Breed-specific weight adjustments

for growth, backfat and loin muscle depth 

Everestus Akanno, PhD, Geneticist, Genesus Inc.


Selection of parents of the next generation of pigs in nucleus breeding programs requires accurate estimation of breeding values for several traits. Among the traits evaluated in a typical swine genetic improvement scheme includes body weight and real time ultrasound backfat and loin depths measured at a given target weight or age.

These traits are collected through performance recording of individual pigs over a wide range of weights and ages. Consequently, adjustment factors are developed to standardized performance information before they are used in genetic evaluation (Moeller et al., 1998, J. Anim. Sci. 76(8):2008-16).

The assumption is that fat accretion and growth rate are linear within a short growth period and differ among pigs, thus, adjusting these performance records will account for differences in growth pattern (Yun Ho Choy et al., 2015, Asian-Australas J. Anim. Sci. 2015 Dec; 28(12): 1696–1702).

Additionally, adjustment factors should be calibrated for different gender and breeds and be reviewed periodically to account for changes in population structure as a result of genetic selection overtime.

At Genesus Inc., individual pigs are performance tested to about 80 kg and 120 kg weight targets. These weight targets represent growth rate from birth after converting to days required to reach 80 kg and 120 kg body weights and are used to adjust ultrasound backfat and loin depths.


To date, Genesus has accumulated over one million individual body weights, backfat and loin depth performance records from several testing locations and covering the three main breeds (Duroc, Landrace and Yorkshire) involved in Genesus Genetic Improvement Program. This has offered us the opportunity to constantly review our adjustment factors and to develop new ones.

Recently, we completed the process of developing new adjustment factors utilizing all available data. Here, adjustment factors for age, backfat and loin depths were developed for specific breeds, sex and weight targets (80 and 120 kg). These new adjustment factors will be used as a genetic evaluation tool:

  1.  To standardized individual pig body weight and ultrasound backfat and loin depths to a common weight targets, thus, reducing variations due to different weights and ages.
  2. To allow the genetic component of performance differences to be accurately estimated.
  3. To accurately identify and select individuals that are genetically superior for growth.     

By collecting more performance records and updating weights adjustment factors with these data, Genesus Inc. will continue to improve and develop its breeding stock and provide best genetics to all it’s customers.

Genesus Research and Development 


The Genesus research and development program is focused on continual improvement of our products and services. Our use of innovative technologies and time-tested methods ensures that our products and services provide our customers a competitive edge.


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