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Author: Verma, Nishant × End date: 2010 × Start date: 2010 ×
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    ThesisItemOpen Access
    Genetic studies on
    (CSKHPKV, Palampur, 2010) Verma, Nishant; Thakur, Y.P.
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    ThesisItemOpen Access
    GENETIC STUDIES ON INHERITANCE OF PART LACTATION MILK YIELDS IN RED SINDHI X JERSEY CROSSBRED COWS
    (CSKHPKV, Palampur, 2010-06) Verma, Nishant; Thakur, Y.P.
    ABSTRACT Records on 136 Red Sindhi x Jersey crossbred cows, maintained at Dairy Farm, Himachal Pradesh Krishi Vishva Vidyalaya, Palampur for 24 years (1981-2004) were analyzed for the effect of genetic group, season of calving, period of calving and parity of cow on cumulative part lactation milk yields. Heritabilities and genetic and phenotypic correlation coefficients were also estimated for these traits. The overall least square means estimated in this study for cumulative milk yields up to 30, 60,120,240 days were 267.46 ± 10.34kg, 548.82 ±21.57kg, 1061.27 ± 40.01kg and 1877.52 ± 59.98 kg respectively. The overall average for other traits viz. 305-days milk yield, total milk yield of lactation, lactation length, peak yield, calving interval, average milk yield per day of lactation length and average milk yield per day of calving interval were 2192.26±65.12kg, 2522.87±80.48kg, 375.11±4.02 days, 459.4±35.17days,12.76±0.36kg, 6.78±0.17kg and 5.61±0.16kg respectively. Cumulative part lactation milk yield traits were only affected by parity of cow. Genetic group, season of calving and period of calving were found to have no significant effect on these traits. The other traits viz. 305-days milk yield, total milk yield of lactation, lactation length, peak yield, calving interval, average milk yield per day of lactation length and average milk yield per day of calving interval, were not affected by genetic group, season of calving and period of calving and parity of cow except 305 days milk yield which was significantly affected by parity of cow. High heritability (0.54±0.19 of 30 days yield to 0.70±0.23 of 120 days yield) and high genetic and phenotypic correlations were observed among different part lactation milk yield traits. The correlation coefficients were moderate to high between part lactation milk yield traits and complete lactation milk yield traits. The high heritability of 60 days milk yield (0.68±0.22), 120 days milk yield (0.70±0.23) and moderate heritability of peak yield (0.324±0.15) and correlations of these traits with other complete lactation milk yield traits indicates that these traits can be utilized as reliable tools for early selection of dairy cows. Low heritabilities for calving interval and lactation length indicates that the length of these traits is much influenced by management and husbandry practices, which can be improved by better management practices.