GTS Red Angus Summary Fall 2007
Using GTS in Sire Selection
GTS Allows Breeders to Make the Most Informed Breeding Decisions in the Industry.
The ABS GTS (Genetic Type Summary) program accurately and objectively describes physical trait differences for individual sires' progeny. By using STAs (Standardized Transmitting Abilities) beef breeders can anticipate the type, or physical characteristics, that a bull will transmit to his offspring. STAs for each trait are calculated using herdmate comparisons on large numbers of a sire's progeny using a linear evaluation system.
These linear proofs are computed using statistical procedures similar to those used to calculate EPDs. STAs indicate how bulls compare for each trait included in the evaluation
STAs also allow breeders to determine where a bull ranks within a given population for each trait. A bull with an STA of 0.0 is average for that trait, compared to all other bulls evaluated. For any given trait, the majority of the sTAs on all bulls evaluated will be near 0.0. In fact, approximately 68 percent of the sires' STAs should fall between -1.0 and +1.0 with over 99 percent between -3.0 and +3.0. Keep in mind that the population dealt with in these GTS analysis is not the entire breed, but a relatively select group of animals that are predominantly A.I. sired.
The number of progeny evaluated is provided in the GTS charts to give breeders an estimate of the reliability of the STAs. The higher the number of progeny evaluated, the greater the reliability of the STAs. For some sires, a Pedigree Estimate (PE) will be given. This indicates that the bull's STAs are based on the STAs of his sire and maternal grandsire, not his progeny.