The Optimum Semen Dilution for the Sperm Quality Index that is Most Predictive of Broiler Breeder Fertility

Abstract

The sperm quality index (SQI) can accurately predict overall semen quality and fertility when broiler breeder semen is diluted, at most, 10-fold prior to analysis. The objective of the present study was to determine if a lower semen dilution rate yields an SQI that is an even better predictor of semen quality and fertility when hens are inseminated with a constant volume of semen. Individual ejaculates from 28 males were analyzed for sperm concentration, viability, and the SQI prior to insemination into 15 hens/male. Semen was diluted 2-, 4-, 8-, 10-, and 25-fold prior to analysis for the SQI. The SQI from 25-, 10-, and 8-fold dilutions produced the strongest correlations with total sperm concentration (r = 0.85, 0.82, and 0.80, respectively). Correlation coefficients for live sperm concentration were highest for the SQI from 25-, 10-, 8-, and 4-fold dilutions (r = 0.86, 0.86, 0.83, and 0.73, respectively). Correlation coefficients were similar for the SQI with fertility from the 4-, 8-, and 10-fold dilutions (r = 0.75, 0.72, and 0.72, respectively). It appears that an 8- to 10- fold SQI dilution is the most consistent at predicting fertility and semen quality.