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 ± ١,٣
٧, 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.
