Aim: To study the magnitude of variation in lactation length (LL), lactation milk yield (LMY) and peak-yield (PY)due to
genetic and non-genetic cases in indigenous and crossbred cattle reared under private dairy unit in and around Gondar,
Ethiopia.
Materials and Methods:The study was conducted on 411 milch animals from 86 dairy farmers comprising of 172 indigenous
and 239 Holstein-Friesian (HF) crossbred cows. These cows were maintained under farmer's management system in and
around Gondar (Ethiopia) and were analyzed by Least squares analysis to study the magnitude of variation in their LL, LMY
and PYdue to genetic and some non-genetic factors.
Result:The overall Least squares means for LL, LMYand PYwere estimated to be 275.1165.23 days, 1407.3471.34 litres and
6.880.38 litres respectively. Genetic group and lactation order had significant effect (P0.01) on LL, LMY and PY. Season of
calving had significant effect (P0.01) on LMY and PY but its effect on LL was non-significant. Effect of location of herd was
significant (P0.05) on LMY and PY while its effect on LL was non-significant. Variations in all the traits due to herd size and
farming system were statistically non-significant.
Conclusion: Productive performance of dairy cows in this study was found to be lesser than the optimum values desirable for
profitable milk production.