Study of Interrelationship among Economically Important Production Traits and Season of Calving on Milk Production in Jersindh Crosses

Study was conducted on productive traits in Jersindh crosses. The data were collected from the records of history sheets maintained in Department of Animal Husbandry and Dairying, SHUATS for the period from 1924 to 1973. The productive traits selected from history sheets were first, second and third lactation milk yield and lactation length and dry period. The mean of 1/4J X3/4RS crosses for 1st ,2nd and 3rd LMY (Kg) were 2259.95, 1963.59 and 1832.74 and for lactation length (days) 378.71, 357.78 and 352 and for Dry period (days) 65.94, 98.23 and 98.26, respectively. The mean of 1/2J X 1/2RS crosses for 1st ,2nd and 3rd LMY (Kg) were 1892.14, 1680.14 and 1789.25 and for lactation length (days) 366.06, 338.75 and 359.43 for Dry period (days) 76.81,61 and 59.93 respectively. The mean of 3/8J X 5/8RS crosses for 1st ,2nd and 3rd LMY (Kg) were 1754, 1843.39 and 3682.36 and for lactation length (days) 320.1, 357.15 and 3 and for Dry period (days) 71.2, 70.7 and 72.35 respectively. The mean of 1/8J X 7/8RS crosses for 1st ,2nd and 3rd LMY (Kg) were 1966.35, 1906.51 and 1837.68 and for lactation length (days) 425.6, 371.75 and 446.4, and for Dry period (days) 71.35, 58.75 and 111.2 respectively. Significant effects of season of calving were observed on 3rd LMY of 1/2J X 1/2RS crosses as well as 3/8J X 5/8RS and 2nd LMY of1/4J X 3/4RS crosses , Second and third lactation length of 1/8 X 7/8 crosses has significant influence on lactation milk yield. Second and third lactation length of 1/4 X 3/4 crosses has significant correlation with lactation milk yield and also the regression of milk yield on lactation length was recorded. Third lactation length of 3/8 X 5/8 crosses has significant correlation with lactation milk yield and also the regression of milk yield on lactation length was recorded. Second lactation length of 1/8 X 7/8 crosses has significant correlation with lactation milk yield and also the regression of milk yield on lactation length was recorded. Out of these crosses (1/4Jx3/4RS,1/2JX1/2RS,3/8 JX5/8RS,1/8JX7/8RS) 3/8JX5/8RS has highest lactation length 652.76 and lactation milk yield is 3682.36.