Expected variations in generation interval in dam of future dams pathway of dairy cows as a result of utilization of sex sorted semen

Using a deterministic model,the changes in generation interval forpathway of dam of dams as a result of sex sorted semenutilization in heifersunder various reproduction conditions was investigated. Three sex sorted semen using strategies were considered.They included continuous usage of sex sorted semen over all inseminations (CS); the use of sex sorted semen atonly first and the second inseminations (S2), and the use of sexed sorted semen atonly the first insemination (S1). Various reproduction situations were described by conception probability associated to using sex sorted semen and conventional one. The results indicated that generation interval by various strategies and reproduction situations varied from 4.0506 to 4.2063 years. Utilization of sex sorted semen by S1 strategy led to shorter generation interval in all situations of reproduction. The shortest range of variation in generation interval under various conditions was due to using S1 strategy (0.08 years) and the highest one was attributed to CS strategy (0.15 years). In general, generation interval for the pathway of dam of dams resulting from using sex sorted semen was longer than that of conventional semen, but was negligible (up to 0.1 years). In the case of necessity for sex sorted semen, it would be recommendable to apply S1 strategy.