Predicting the rate of inbreeding in populations undergoing four-path selection on genomically enhanced breeding values

Abstract

Objective: A formula is needed that is practical for current livestock breeding methods and that predicts the approximate rate of inbreeding (∆F) in populations where selection is performed according to four-path programs (sires to breed sons, sires to breed daughters, dams to breed sons, and dams to breed daughters). The formula widely used to predict inbreeding neglects selection, we need to develop the new formula can be applied with or without selection. Methods:The core of the prediction is to incorporate the long-tern genetic influence of the selected parents in four-selection paths executed as sires to breed sons, sires to breed daughters, dams to breed sons, and dams to breed daughters. Our prediction method is based on the concept of long-term genetic contributions. The selective advantage of the parents in four-selection paths was described in the linear model. The rate of inbreeding was computed as the magnitude that is proportional to the sum of squared long-term genetic contributions of the parents of four-selection paths to the selected offspring. A c c e p t e d A r t i c l e3 Results: We developed a formula to predict the rate of inbreeding in populations undergoing four-path selection due to index or single-trait selection according to on genomically enhanced breeding values and with discrete generations. Generations were regarded as discrete under the assumption that number of parents in four-path selection and magnitude of selection intensity were the same throughout the usage period of several years. When the effects of selection on the rate of inbreeding were neglected in the formula developed here, the predicted rates of inbreeding agreed with those from the previously reported and widely used formula, which neglects selection, i.e., The new formula can be applied with or without selection. Neglecting the effects of selection led to underestimation of the rate of inbreeding by 40% to 45%. Conclusion:The formula we developed here would be highly useful as a practical method for predicting the approximate rate of inbreeding (∆F) in populations where selection is performed according to four-path programs.

Development of an index that decreases birth weight, promotes postnatal growth and yet minimizes selection intensity in beef cattle

“…Even when the same magnitude of genetic gain is achieved at a particular time point, the lower the intensity of selection, the lower the inbreeding coefficients [15]. In addition, the lower the selection intensity, the more likely the selection goal will be achieved.…”