Effect of calving years, season, age and parity classes on productive and reproductive performance of Holstein-friesian cows at Holetta sate dairy farm
2000
Nega Tolla | Sendros Demeke
Six-hundred thirty four production and reproduction data over 8 years period (1989-1996) collected from Holetta state dairy farm was analyzed using General Linear Model (GLM) of SPSS (1998). There was significant (p0.05) calving year effect on both lactation and daily milk yield, which may be resulted due to inconsistent management practices. Calving season had no significant (p0.05) effect on these production parameters. Age and parity class had significant effect (p0.05) on both lactation and daily yield. The intervals (Days) from calving to first service (CFS), calving to positive services (CPS), number of services per conception (SPC) and calves birth weight (CBWT) were significantly (p0.05) affected by calving year, age and parity class while calving season had no significant effect on these reproduction parameters. Finally it was recommended that in order to maintain optimum milk yield, cows above the age of 8 years have to be culled and replaced timely, paying due attention for individual animals with exceptionally higher performance. In addition, consistent management practice is needed for optimum production and reproduction performance of the herd.
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