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Estimation of relative economic values for production and non-production traits from field data, using profit functions
Abstract
Lifetime production records of 122,679 cows and production data of 691,383 lactations obtained from MidStates Dairy Records Processing Center, Ames, lowa, were used to estimate relative economic values for production to herd life and production to somatic cell score. Using lifetime production data, relative net income and relative net income for the planning horizon were calculated as income minus costs. Planning horizon of five lactations was chosen and cows culled before fifth lactation were credited with profit from replacements to obtain relative net income for the planning horizon. Income was from sale of milk, calves and cull cows. Costs were for heifer rearing, feed, labor and breeding. Profits were regressed on milk, fat and protein yields, and herd life. Regression coefficients were multiplied by unadjusted phenotypic standard deviations of traits to obtain relative economic values. Relative economic value for production to herd life was.18:1 for relative net income, and.46:1 for relative net income for planning horizon. Value of herd life was overestimated by about 2.5 times when profit from replacements was ignored. Heritability of herd life estimated using animal and sire models of.50 was used to obtain predicted transmitting abilities for herd life. As the estimated heritability was higher than most estimates from literature, predicted transmitting abilities for herd life were calculated for different values of heritability (.05,.10,.20,.50). Profits were regressed on predicted transmitting abilities for milk, fat and protein yields, and herd life. Relative economic values obtained from regression coefficients and standard deviations of predicted transmitting abilities, were similar to relative economic values obtained when profits were regressed on phenotypic measures. For profit regressed on predicted transmitting abilities, relative economic values did not differ much with change in assumed heritability of herd life. Relative net income per lactation was obtained for 691,383 lactations as income minus costs, to estimate relative economic value of production to somatic cell score. Income was from milk, fat and protein yields, and premium for somatic cell count. Costs were from breeding, feed and labor requirements. Relative net income per lactation was regressed on production yields and somatic cell score. Regression coefficients were multiplied by unadjusted phenotypic standard deviations of traits to obtain relative economic value for production to somatic cell score, which was 1:$-$.21. Large negative value for somatic cell score was mostly due to premiums paid for somatic cell count because, relative values were 1:$-$.015 when premiums for somatic cell count were not used in calculating income.
Subject Area
Agricultural economics|Biostatistics
Recommended Citation
Jagannatha, Shylaja, "Estimation of relative economic values for production and non-production traits from field data, using profit functions" (1996). ETD collection for University of Nebraska-Lincoln. AAI9637071.
https://digitalcommons.unl.edu/dissertations/AAI9637071