Genetic and non-genetic factors influencing sperm motilities of beef bulls during cryopreservation process

Abstract

This study aimed to evaluate genetic and non-genetic factors affecting motility after the cryopreservation process. Sperm motility records of five breeds of Bulls were obtained from Singosari National Artificial Insemination Center of Indonesia. A data set comprised 36754 records of ejaculation collected from 143 bulls. The records comprised progressive motility of fresh semen (PMFS), pre-freeze motility of liquid semen (PMLS), and post-thawing motility (PTM). The MIXED procedure with Tukey–Kramer multiple comparisons and Pearson correlation of Statistical Analysis System (SAS) was used for data analysis. This study shows that breed, season, age, and ejaculation influence the PMFS. In five breeds, the youngest bulls produced fresh semen with the lowest progressive motility. The highest PMFS occurs at high precipitation in Bali, Limousin, and Simmental. PMFS for Brahman and Ongole Grade was not significantly affected by precipitation. The first ejaculate is higher than the second ejaculate except for the Limousin and Simmental. PMLS and PTM were significantly different between the breeds. PMLS of Bali, and Limousine bulls were significant between different seasons, whereas that of Brahman, Ongole Grade, and Simental were not. The differences in the age of bulls were not shown in Bali bulls. PTM for all the breeds was significant between different seasons, except for Ongole Grade bull. All breeds showed the highest PTM in the season with medium precipitation, except for Ongole Grade bull. The highest post-thawing motility in five breeds was observed in the youngest bull. The heritability value of motility traits is included in the medium category (0.23 – 0.28). The phenotypic correlation between the motility of fresh semen, liquid semen, and frozen semen was low (0.14-0.15) but still correlated (p<0.05).