+ Site Statistics
+ Search Articles
+ PDF Full Text Service
How our service works
Request PDF Full Text
+ Follow Us
Follow on Facebook
Follow on Twitter
Follow on LinkedIn
+ Subscribe to Site Feeds
Most Shared
PDF Full Text
+ Translate
+ Recently Requested

Lactation curves of purebred and crossbred dairy cattle



Lactation curves of purebred and crossbred dairy cattle



Journal of Dairy Science 69(1): 195-203



First lactations of 397 cows with varying percentages of Holstein and Guernsey breeding provided a means of studying genetic and environmental effects on coefficients of the lactation curve y = anbe-cn (1 + u sin(x)+v cos(x)), where a, b, c, u, and v are coefficients to be estimated; e is the base of natural logarithms (in); n is the day of lactation; and x is the day of year. The logarithmic form of the equation ln (y) = ln(a) + b ln(n) + cn + u sin(x) + v cos(x) was fit for each cow. Analysis of variance on each estimated coefficient used a fixed model with genetic and environmental factors. There was no evidence of additive genetic variation associated with coefficients of the lactation curve except for ln(a), the initial yield or general scaling of the curve. There was some evidence of nonadditive genetic variation with significant interaction of breed of sire with breed of dam. There was no effect for age fresh or days open on any coefficient; however, effects of year fresh and month fresh on most coefficients were highly significant. To change the shape of the lactation curve through selection probably would not be successful; however, initial production or scaling of the curve probably can be changed. It may be possible to change the shape of the lactation curve by exploiting nonadditive genetic variance.

Please choose payment method:






(PDF emailed within 0-6 h: $19.90)

Accession: 001399638

Download citation: RISBibTeXText

DOI: 10.3168/jds.s0022-0302(86)80386-1


Related references

Lactation production by purebred and crossbred dairy cattle. J. Dairy Sci, 48: 6, 791, 1965

Growth and reproduction characteristics of purebred and crossbred dairy cattle in first lactation. Journal of Dairy Science 69(3): 782-793, 1986

Comparison of two mathematical models for fitting the lactation curve in purebred and crossbred dairy cattle. Canadian Journal of Animal Science 66(1): 322, 1986

Factors affecting culling and survival during rearing and first lactation in purebred and crossbred dairy cattle. Animal Production 46: 1-12, 1987

Functions for lactation curves in crossbred dairy cattle. Indian Journal of Animal Sciences 55(1): 42-47, 1985

First lactation performance of crossbred and purebred exotic cattle in Indo-Gangetic plains. Indian Journal of Dairy Science 32(4): 355-361, 1979

Livability of purebred vs crossbred dairy cattle. Jour Dairy Sci 44(5): 879-887, 1961

Causes of mortality in purebred and crossbred dairy cattle. Indian Veterinary Journal 84(6): 607-609, 2007

Performance of crossbred and purebred dairy cattle. J. Anim. Sci, 23: 3, 850, 1964

Reproductive efficiency of purebred and crossbred dairy cattle. Journal of Dairy Science 57(2): 220-234, 1974

Performance of purebred and crossbred dairy cattle in Thailand. Animal Production 21(3): 209-216, 1975

Some aspects of fertility in purebred and crossbred dairy cattle. Anim. Prod, 10: 465-471, 1968

Economic merit of crossbred and purebred US dairy cattle. Journal of Dairy Science 86(3): 1036-1044, 2003

Efficiency of milk production in first lactation of crossbred and European purebred cattle, in Indo-Gangetic Plains. World Review of Animal Production 15(3): 4, 6, 8, 73-80, 1979

Crossbred and purebred dairy cattle in warm and cool seasons. Journal of Dairy Science 66(11): 2408-2417, 1983