Records of ٤٤٥ Friesian cows were analysed for calving interval and its components; days open, lactation length and length of dry period. The model included parity, calving year and calving season. The overall means were ٤٢٥,٧٧ ± ١,٨٩, ١٤١,٣ ± ١,٣٧, ٣٥٣,٩ ± ٠,٨٨ and ٧٣,٠٢ ± ٠,٧٧ days for calving interval, days open, lactation length and length of the dry period respectively. These estimates are high by tropical and subtopical standards, but they remain lower than the reproductive performance of Friesian cattle in temperate countries.