LIFETIME MILK PRODUCTION EFFICIENCY OF JERSEY COWS UNDER SUB-TEMPERATE CONDITIONS

Lifetime performance  and disposal data on 154 Jersey cows, progeny of 14 sires getting disposed off due to natural reasons after completing at least one lactation of more than 180 days duration from the dairy herd of Instructional livestock farm, CSK, Himachal Pradesh Krishi Vishvavidyalaya, Palampur were utilized to evaluate the lifetime production efficiency in terms of milk yield per day of herd life,  milk yield per day of total lactation period and  milk yield per day of longevity of the exotic Jersey cows in sub-temperate climatic conditions of Himachal Pradesh to judge overall suitability and adaptation of the breed to native environs. The overall least squares means estimated for lifetime milk yield per day of herd life, lifetime milk yield per day of total lactation length and lifetime milk yield per day of longevity were 4.77±0.18 kg, 6.46±0.13 kg and 2.92±0.12 kg respectively. The mean performance for these traits was comparable to earlier estimates reported for Jersey and its crossbred cows in different agro climatic regions of the country. The analysis of  different factors affecting these traits revealed period of calving and first lactation milk yield as significant sources of variation for milk yield per day of herd life and lactation period while the age at first calving and first lactation milk yield significantly influenced milk yield per day of longevity. The results suggested reasonably good performance and adaptation of the breed in local agro climatic conditions and validated the effect of existing culling of low yielders based on first lactation yields.