Survival Rates and Productive Herd Life of Dairy Cattle in the United States From: Journal of Dairy Science | Date: September 1, 2006| Author: Norman, H D; Wright, J R; Hare, E | Copyright American Dairy Science Association Sep 2006. Provided by ProQuest LLC.Copyright information

ABSTRACT

Survival rates and productive herd life were examined for 13.8 million US dairy cows that calved from January 1, 1980, through March 2, 2005. Cows that left the herd for dairy purposes or were from herds that discontinued Dairy Herd Improvement testing were excluded from any calculations to prevent underestimation of population longevity. Mean lactation length for cows without subsequently recorded lactations ranged from 205 to 235 d across breed-parity subsets and were 4 to 2...

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