Seasonal Variation and Age-Related Changes in Semen Quality of Limousin Bull in Indonesian Artificial Insemination Center

The objective of this study was to determine the effect of season and age on semen quality (individual motility, mass motility, concentration, volume, pre-freeze motility, and post-thaw motility) of Limousin Bull under the tropical condition in Indonesian artificial insemination center. This study used a large data set recorded over eight years (2011 until 2018) of production period (n = 6758 ejaculates, n = 19 bulls) retrieved from Singosari National Artificial Insemination Center. Rainfall and other climatic data were collected from Malang Meteorological, Climatology, and Geophysics Agency, Indonesia. Seasonal effect was grouped into three groups, i.e. rainy season (total rainfall per month >200mm), humid season (total rainfall per month = 100-200 mm), and dry season (total rainfall per month