Abstract

Zewdu V. Bainwad

This research was conducted to evaluate the effect of non-genetic factors on milk production of Holstein Friesian × Deoni crossbred cows. Data representing 256 HF × Deoni crossbred cows from cattle crossbreeding project with 1485 total records of lactation over a 30 years period were analyzed to determine the effects of period of calving, season of calving, age at first calving and parity on milk production. The overall least squares mean of lactation milk yield, 305 days milk yield, lactation length, and milk yield per day of lactation length were 1661.35±15.17, 1707.25±13.25, 296.80±2.29 and 5.65±0.04 kg, respectively. All sources of variation were significant except season of calving for 305 days milk yield and lactation length; age at first calving for 305 days milk yield and milk yield per day of lactation length. Milk production was depressed for cows calving in summer. First lactation cows had lowest
milk production, and highest production occurred in 5th parity. It was therefore, concluded that, HF × Deoni crossbred cows were affected by non-genetic factors.