Abstract
A total of 6,804 records for Duroc breed were collected from three farms registered at the Korean Animal Improvement Association (KAIA) from 1998 to 2004 of which both records from two ultrasound modes (A and B) were analyzed to estimate the variance components of carcass traits. Three carcass traits backfat thickness (bf), loin eye muscle area (Ima) and lean meat percentage (Imp) were measured. These traits were analyzed separately as bfl, Imal and lmp1 for ultrasound mode A and bf2, lma2 and lmp2 for ultrasound mode B with multiple trait animal model by using MTDFREML (Boldman et al., 1993). All the traits revealed medium heritability values. Estimated heritabilities for bfl, bf2, Imal, lma2, lmp1 and lmp2 were 0.45, 0.39, 0.32, 0.25, 0.28 and 0.39, respectively. Estimated genetic correlations for traits bfl and bf2, Imal and lma2, Impi and lmp2 were positive but low. Specifically, genetic correlations between bfl and bf2 was 0.30 while the estimates for lean traits between Imal and lma2 and between Impi and lmp2 were 0.15 and 0.18, respectively. Conversely, high negative genetic correlations existed between bfl and the lean traits lma2, lmp2. Likewise, the estimated genetic correlations between Imal and lma2 and Impi and lmp2 were low.
Highlights
With the changes in the swine industry, the knowledge of genetic control of pork quality traits is required to implement selection programs which maximize the genetic gain in the swine population that emphasize product quality
The purpose of this study was to estimate the genetic parameters of carcass traits using data collected by both loin meat area end test +(90kg - end weight )× loin meat area at end test lma1& lma2 =
The data set used 6,804 performance records of pure breed Duroc from three farms which collected data both for ultrasound mode A and B that were registered at Korean Animal Improvement Association (KAIA) from 1998 up to 2004 (Table 1)
Summary
With the changes in the swine industry, the knowledge of genetic control of pork quality traits is required to implement selection programs which maximize the genetic gain in the swine population that emphasize product quality. Real-time ultrasound measurements of backfat thickness and longissimus muscle area are being used increasingly in swine selection programs. Ultrasound mode A gives point estimate of characteristics of the tissue of interest. According to Moeller (2002) it is accurate for backfat depth but inconsistent for loin depth. The ultrasound mode B gives highly accurate results for both backfat and loin muscle area. The accuracy of mode A was often less than ideal, the relatively low investment cost and the perceived ease of operation made them widely used for seedstock selection, central testing programs, university, industry research and on-farm applications
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