National Sheep Improvement Program (NSIP) and the Suffolk breed. By Alan Culham History of NSIP The National Sheep Improvement Program was established in 1987 with its first processing center located at Iowa State University. This was the first opportunity for U.S. sheep seedstock producers to obtain genetic evaluations for performance traits using BLUP technology. As of December 2015, pedigree data on 54,807 Suffolk sheep from 105 flocks, which included 2,965 sires and 13,436 dams have been included in the analysis. Weaning weights collected between 1983 and 2015 on 35,802 lambs from 101 Suffolk flocks also were available, and contained 2,009 contemporary groups. These first expected progeny differences (EPDs) were limited to being used for within flock comparisons and were called flock expected progeny differences or FEPDs. A lack of adequate established genetic connections between enrolled flocks of a particular breed was the cause for this limitation.
In 1995 an analysis of genetic connections was conducted by Dr. Dave Notter, Department of Animal Science, Virginia Polytechnic Institute and State University. It was revealed that adequate genetic linkages existed between most enrolled NSIP Suffolk flocks to allow across flock comparisons of individual sheep EPDs. Prior to 1995 little genetic improvement was realized in the Suffolk breed. This could be attributed to the biological time lag in accumulating adequate performance data to identify individual sheep of superior genetic merit and the lack of ability to compare animals between flocks. After the 1995 transition to across flock comparison of EPDs, dramatic breed improvement occurred in those traits of importance to the breed. (Figure 1) Figure 1 In 2010 the processing of NSIP data was transferred to Lambplan – Australia. This resulted in several major changes in the transmission and look of our NSIP data. Some of the Average increase of eight pounds in 120 day weight changes:
Individual genetic evaluations for each trait were now in the form of Estimated Breeding Values (EBVs). EBVs measure the total genetic merit of an individual for a trait. EPDs that had been used previously measured the expected difference in performances of an animal’s offspring. Since one half of the resulting offspring’s gene come from each parent an EPD can be derived by simply dividing an animal’s EBV by 2. EBVs were expressed in metric values, kilograms, millimeters, etc.
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Four pound average increase in 60 day weight
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