Bhoite.U.Y.Khekare.M.M.2019-02-252019-02-252014http://krishikosh.egranth.ac.in/handle/1/5810096794The data on milk production traits of 5/8 Gir crossbreds and Phule Triveni cows maintained at RCDP on Cattle, M.P.K.V., Rahuri, Dist.- Ahmednagar, Maharashtra (India) over a period of 37 years (1977-2013) were used for present study. Least squares means of lactation milk yield (LMY), 300 days milk yield (300 DMY), lactation length (LL) and dry period (DP) were worked out as suggested by Harvey (1990) to estimate the effects of genetic group, season of calving, period of calving and order of lactation. Wherever the effects were significant, mean values were compared by Duncan’s Multiple Range Test (DMRT) as modified by Kramer (1957). The correlations among the production traits under study were also estimated. The overall least squares means of LMY, 300 DMY, LL and DP in 5/8 Gir crossbreds were 3016.66 ± 101.28 kg, 2794.56 ± 84.84 kg, 332.00 ± 6.61 days and 91.29 ± 6.61 days respectively. The overall least squares means of LMY, 300 DMY, LL and DP in Phule Triveni were 3106.39 ± 48.19 kg, 2879.46 ± 38.40 kg, 334.18 ± 3.22 days and 86.28 ± 3.93 days respectively. The effect of genetic group on LMY, LL and DP was significant (P < 0.01) while, it was non-significant on 300 DMY. The variation due to season of calving in LMY, 300DMY, LL and DP was non-significant in 5/8 Gir crossbreds and Phule Triveni. The influence of period of calving on LMY, 300 DMY, LL and DP was significant in Phule Triveni (P < 0.01) and non-significant in 5/8 Gir crossbreds. The difference due to lactation order in LMY and 300 DMY was significant (P < 0.01) in 5/8 Gir crossbreds and Phule Triveni, whereas, non-significant in LL and DP. Phenotypic correlations of LL with LMY and 300 DMY were positive and significant (P < 0.01) while it was negative and non-significant between LL and DP in 5/8 Gir crossbreds and Phule Triveni. Phenotypic correlations of DP with LMY and 300DMY were positive and non-significant in 5/8 Gir crossbreds whereas, negative and non-significant in Phule Triveni. Phenotypic correlation between LMY and 300DMY was positive and significant (P < 0.01) and LL with LMY and 300 DMY was positive and significant in 5/8 Gir crossbreds and Phule Triveni. Genetic correlations of LL with LMY and 300 DMY were positive and significant (P < 0.01) while it was negative and non-significant between LL and DP in 5/8 Gir crossbreds and Phule Triveni. Genetic correlation between DP and LMY was positive and non-significant in 5/8 Gir crossbreds and Phule Triveni. Genetic correlation between DP and 300DMY was negative and non-significant in 5/8 Gir crossbreds and Phule Triveni. Genetic correlations between LMY and 300DMY was positive and significant (P < 0.01) in 5/8 Gir crossbreds and Phule Triveni.enThesis