Some factors influencing peak yield and days attain to peak yield in Friesian cattle in the central region of Iraq

الملخص EN

This study was under taken on 950 lactation records kept at Iraq-Jordinian company / Dujaila- Wasit Governorate during a period from 2001-2003.to evaluate the effect of some non-genetic factors (age at 1st calving,parity,season of calving ,year of calving and service period ) on peak milk yield and days to attain peak yield .The least-squares means for peak milk yield and days to attain peak yield were :14.252± 4.763 kg and 47.528 ± 24.121 days.Peak milk yield was significantly influenced (p<0.05) by season and year of calving ( p<0.01).

Days to attain peak yield was significantly ( p<0.05) influenced by year of calving.