Study of some environmental factors affecting on reproductive performance and milk production of dairy Friesian cows

Abstract EN

A total number of 1243 records for 585 dairy Friesian cows during the consecutive 8 years from 1997 to 2004 were used to study the effect of some environmental factors on reproductive performance of dairy Friesian cows.

The obtained results showed that the length of service interval, service period, days open and calving interval decreased significantly (P<0.05) with increasing body weight of cows.

Conception rate increased significantly (P<0.05), while the number of service per conception decreased significantly (P<0.05) with increasing cows weight.

The length of service interval, service period, days open and calving interval and the number of service per conception decreased significantly (P<0.05) with advancing age up to 9 years and tended to increase thereafter.

Conception rates increased significantly (P<0.05) with the progress of age up to 9 years and decreased afterwards.

The length of service interval, service period, days open and calving interval and the number of service per conception decreased significantly (P<0.05) with the progress of parity up to 5th and increased afterwards.

The conception rates increased significantly (P<0.05) up to the 5th parity and decreased thereafter.

There were significant (P<0.05) differences in reproductive traits of dairy Friesian cows among the different calving years.

Calving season affected significantly (P<0.05) only on conception rates entire the first 120 and 150 day of lactation as well as number of service per conception.

There were no significant (P<0.05) differences in reproductive intervals, conception rate and number of service per conception between feeding winter and summer rations.