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3.4 Lactation Curves

Published online by Cambridge University Press:  27 February 2018

P. D. P. Wood*
Affiliation:
Milk Marketing Board, Thames Ditton, Surrey
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Extract

An algebraic description of the lactation curve is a useful component of any model of the day-to-day production of lactating animals. Observation and common sense suggest that such a function should rise to a peak early in lactation and decline thereafter but simpler models have been used. Ostergaard (1979), for example, used a linear model to study strategies for concentrate feeding to obtain optimum feeding levels in high yielding dairy cows. His model was

where y (t) was the yield in week t and a and b were the usual linear regression coefficients. The error term is omitted here and elsewhere for clarity. Gaines (1927) used the decay function

where A and k are the constants fitted to log y (t).

These models, one linear, the other exponential, peak in Week 1 and require only two parameters. In this paper, more sophisticated functions are described and compared.

A lactation curve is assumed to contain two components, one of which is the intrinsic biological drive to produce milk and the other is an environmental constraint upon it. The algebra may be justified by biological argument according to the skill and the leanings of the modeller.

Type
3. Model Building
Copyright
Copyright © British Society of Animal Production 1981

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References

REFERENCES

Cobby, J. M. and Le Du, Y. L. P. 1978. On fitting curves to lactation data. Anim. Prod. 26: 127133.Google Scholar
Gaines, W. L. 1927. Persistency of lactation in dairy cows. Illinois agric. Exp. Stn Bull. No. 288.Google Scholar
King, J. O. L. 1978. The effect of visiting parties on milk production in cows. Vet. Ree. 102 (16): 361362.Google Scholar
Minder, C. E. and McMillan, I. 1977. Estimation of linear compartmental model parameters using marginal likelihood. Biometrics 33: 333341.CrossRefGoogle Scholar
Ostergaard, V. 1979. Strategies for concentrate feeding to attain optimum feeding level in high yielding dairy cows. Nat. Inst. Anim. Sci., Copenhagen. Rep. 482.Google Scholar
Schaeffer, L. R., Minder, C. E., McMillan, I. and Burnside, E. B. 1977. Non linear techniques for predicting 305-day lactation production of Holsteins and Jerseys. Am. J. Dairy Sci. 60: 16361644.CrossRefGoogle Scholar
Wood, P. D. P. 1967. Algebraic model of the lactation curve in cattle. Nature, Lond. 216: 164165.CrossRefGoogle Scholar
Wood, P. D. P: 1969. Factors affecting the shape of the lactation curve in cattle. Anim. Prod. 11: 307316.Google Scholar
Wood, P. D. P. 1970. The relationship between the month of calving and milk production. Anim. Prod. 12: 253259.Google Scholar
Wood, P. D. P. 1979. A simple model of lactation curves for milk yield, food requirement and body weight. Anim. Prod. 28: 5563.Google Scholar
Wood, P. D. P. 1980. Breed variations in the shape of the lactation curve of cattle and their implications for efficiency. Unpubl.CrossRefGoogle Scholar