Department of Livestock Production and Management, College of Veterinary Science, Assam Agricultural University, Khanapara, Guwahati-781022.
Under field conditions of Assam the least square means of lactation milk yield for Jersey X Local, Holstein Friesian X Local and Local cows were 1629.764 ± 15.597, 2045.336 ± 17.712 and 307.502 ± 17.787 liters respectively. Corresponding values of lactation length were 271.920 ± 1.582, 304.902 ± 1.797 and 241.508 ± 1.805 days and dry period 122.458 ± 1.998, 117.488 ± 2.254 and 297.079 ± 2.256 days respectively. The effect of genetic group, season of calving and lactation order was highly significant (p<0.01) on these three traits. Significantly highest lactation milk yield was in south west monsoon calves, highest lactation length was in summer mansoon calves and highest dry period was in winter calves. The lactation milk yield and lactation length gradually increased from first to third lactation while dry period showed reverse trend.
Lactation milk yield, lactation length, dry period, crossbred, local cows
