Vol. 9, Special Issue 1 (2024)

The present study was conducted at Livestock Research Station, Mahanandi, Andhra Pradesh for finding out the phenotypic correlations among the production and reproduction traits in Ongole cows. The data regarding the production traits (birth weight of calf, 305 day lactation milk yield, total lactation milk yield, peak yield and lactation length) and reproduction traits (age at first calving and calving interval) were calculated and/or collected from the daily production records and history sheets available in the farm. The mean values of age at first calving (yr), calving interval (yr), birth weight of calf (kg), lactation length (days), 305 day lactation milk yield (kg), total lactation milk yield (kg), daily peak yield (kg) and weekly peak yield (kg) were 4.948±0.074, 1.571±0.045, 27.875±0.233, 330.188±7.255, 750.972±21.143, 850.280±29.445, 4.170±0.097 and 24.877±0.658 respectively. The phenotypic correlations of age at first calving with calving interval, birth weight of calf, 305 day lactation milk yield, total lactation milk yield, peak yield and lactation length were -0.192, -0.110, -0.417, -0.379, -0.545 and 0.116 respectively which were changed to -0.160, -0.115, 0.559, 0.406, 0.441 and 0.091 during sixth and above lactations. It was found that the birth weight of calf was found to be negatively associated with the age at first calving during second lactation and with calving interval from third lactation onwards. The 305 day lactation milk yield positively correlated significantly (p<0.01) with total lactation milk yield, and peak yield and lactation length. From the results, it was concluded that the phenotypic correlation between the age at first calving and milk yield traits such 305 day lactation milk yield and peak yield changes from negative to positive with increase of lactation number, and there is a general trend of positive relation among the milk production traits in all the lactations.