Santa Gertrudis Source April 2024

TO DRIVE GENETIC IMPROVEMENT IN YOUR HERD THE POWER OF GENOMICS HARNESS

BY BOB WEABER, PH.D. | PROFESSOR AND HEAD, EASTERN KANSAS RESEARCH AND EXTENSION CENTERS KANSAS STATE UNIVERSITY | SGBI GENETIC EVALUATION CONSULTANT

to 50 percent. The genotype information is used to estimate the fraction of genetics traceable to each grandparent after parentage is checked. Adjustment

D NA genotyping of young breeding candidates and existing breed ing bulls and heifers provides powerful insights into the genetic merit of Santa Gertrudis selection candidates and em powers future breeding deci sions. Modern genomic tools and genetic evaluation systems that leverage genotypes, per formance data and pedigree information provide impactful tools that allow commercial and seedstock breeders to make mating decisions with precision and confi

of kinship allows for weighting of the influence of grandparents’ genetic merit in prediction of a grand-progeny’s EPD.

Genotyping existing cows can identify errors in pedigrees, im proving EPD reliability through correction of kinship. Typical pedigree error rates, even in very well-managed herds, can range from 5 to 10 percent due to inadver tent recordkeeping errors, estray bulls, cows switching calves and even errors in se men selection from the AI tank. Genotyping tests easily find those errors and often provide a path to resolv ing them. The inclusion of a revised kinship and construction of reliable pedigrees increases the accuracy and reliability of EPDs. Improved EPD accuracies mean more reliable mat ing decisions can be made for your genotyped cows, en abling more rapid genetic improvement. Genotyping replacement heifer candidates prior to se lection provides an effective way for producers to plot out their genetic destiny. Genomics adds more accuracy to female EPDs than their lifetime production of natu ral calves for many traits. Knowing the genetic merit for calving ease, stayability, carcass and maternal traits with high reliability at the time of selection rather than having to wait until the cow or progeny make production records is a game changer. Collecting phenotypes on economically important traits and adding genomic information to the data stream dramatically strengthens your decision-mak ing ability. Making investments that help capture genetic information early in an animal’s life is essential to remain ing competitive in the seedstock marketplace. Use Genomically Informed EPDs to Make Decisions In addition to using genomics to inform EPDs for re placement females, genotyping sale bull candidates aides in selection and marketing. Increased EPD accuracies means culling and selection decisions are more precise. Consider genotyping bulls prior to weaning or shortly thereafter to

dence. Breeders utilizing these tools can make rapid changes in trait merit aligned with their breeding objective. The genomic tools are particularly helpful in providing insight into traits that are difficult, time consuming and/or expensive to measure. Effective genomic tools require the association of varia tion in genotype with variation in phenotype. Hence, Santa Gertrudis Breeders International (SGBI) and breeders need a broad sampling of the population to detect a geno type that appears with favorable performance and an alter nate genotype that is associated with inferior performance. If only the “best animals” are sampled for genotyping, only the good genotype is represented in our sample. Breeders should consider investing in genotyping to improve ex pected progeny differences (EPDs) accuracy of the cow herd. This includes genotyping replacement female candi dates and using the resulting EPDs in selection decisions. The Value of a Genotyped Cow Herd Having a genotyped cow herd benefits seedstock pro ducers in several ways. First, it means the pedigrees of cur rent cows are parent verified. Having accurate pedigrees is a key step in production and reporting of accurate EPDs. The Neogen genetic evaluation system that computes SGBI EPDs utilizes genomic information to adjust the kin ship between animals in the database. This method allows for differing relationship between animals and their grand parents. On average, animals are expected to have 25 per cent of their genetic material from each grandparent but, due to random assortment among pairs of chromosomes during formation of sperm and egg, this can range from 0

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SANTA GERTRUDIS SOURCE

APRIL 2024