Skip to main content Accessibility help
×
Home
Hostname: page-component-59b7f5684b-ns2hh Total loading time: 0.431 Render date: 2022-09-28T14:05:55.414Z Has data issue: true Feature Flags: { "shouldUseShareProductTool": true, "shouldUseHypothesis": true, "isUnsiloEnabled": true, "useRatesEcommerce": false, "displayNetworkTab": true, "displayNetworkMapGraph": false, "useSa": true } hasContentIssue true

A comparison among equations to characterize lactation curves in beef cows

Published online by Cambridge University Press:  02 September 2010

W. D. Hohenboken
Affiliation:
Department of Animal Science, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
A. Dudley
Affiliation:
Department of Animal Science, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
D. E. Moody
Affiliation:
Department of Animal Science, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA
Get access

Abstract

Monthly and fortnightly milk production records were analysed from 59 autumn-calving Angus and Angus × Holstein crossbred cows. Half the cows had been administered 10 mg thyroxine per day from day 60 to 120 of lactation and half were controls. Four published equations to characterize individual lactation curves were compared. These were: (1) log Y(n) = log –a1 + b1log n – c1n (Wood); (2) equation 1 with each log Y(n)2 weighted by Yin)2 (Wood weighted); (3) log [Y(n)/n7 = log l/a3 – k3n(Jenkins); and (4) log Y(n) = a4 – b4n‘(l + 25·5 n’) + c4n2 = d 4/ n (Morant), where Y(n) is milk yield on day n of lactation, n' is n–110 (the mid point of lactation), and the a, b, c, k and d parameters are estimated from solution of the equations. The lactation curve from the Jenkins equation projected peak milk yield to occur some 30 days later than estimates from the other equations. It underestimated production early and late in lactation and overestimated it during mid lactation. For several cows, the Morant equation projected that peak production occurred at the end of lactation. Also, analysis of variance of milk production variables was less sensitive when the traits were estimated by the Morant equation than when they were estimated by one of the others. The Wood weighted equation resulted in estimates of peak day of lactation and peak yield that were less variable and more realistic than estimates from the Wood equation. Collectively, therefore, the Wood weighted equation was deemed most suitable to characterize variability among and within these beef cows in milk production. All four equations, however, ranked the 59 cows similarly for estimated 220-day yield.

Type
Research Article
Copyright
Copyright © British Society of Animal Science 1992

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Clutter, A. C. and Nielsen, M. K. 1987. Effect of level of beef cow milk production on pre- and postweaning calf growth. Journal of Animal Science 64: 13131322.CrossRefGoogle ScholarPubMed
Cobby, J. M. and Le Du, Y. L. P. 1978. On fitting curves to lactation data. Animal Production 26:127133.CrossRefGoogle Scholar
Jenkins, T. G. and Ferrell, C. L. 1984. A note on lactation curves of crossbred cows. Animal Production 39: 479482.CrossRefGoogle Scholar
Lubritz, D. L., Forrest, K. and Robison, O. W. 1989. Age of cow and age of dam effects on milk production of Hereford cows. Journal of Animal Science 67: 25442549.CrossRefGoogle ScholarPubMed
Montaño-Bermudez, M. and Nielsen, M. K. 1990. Biological efficiency to weaning and to slaughter of crossbred beef cattle with different genetic potential for milk. Journal of Animal Science 68: 22972309.CrossRefGoogle ScholarPubMed
Moody, D. E., Hohenboken, W. D., Beal, W. E. and Thye, F. W. 1992. Concentration of plasma cholesterol in beef cows and calves, milk production and calf gain. Journal of Animal Science 70: In Press.CrossRefGoogle ScholarPubMed
Morant, S. V. and Gnanasakthy, A. 1989. A new approach to the mathematical formulation of lactation curves. Animal Production 49:151162.CrossRefGoogle Scholar
Rowlands, G. J., Lucey, S. and Russell, A. M. 1982. A comparison of different models of the lactation curve in dairy cattle. Animal Production 35:135144.CrossRefGoogle Scholar
Statistical Analysis Systems Institute. 1985. SAS user's guide: statistics. SAS Institute Inc., Cary, NC.Google Scholar
Wood, P. D. P. 1967. Algebraic model of the lactation curve in cattle. Nature, London 216:164165.CrossRefGoogle Scholar
7
Cited by

Save article to Kindle

To save this article to your Kindle, first ensure coreplatform@cambridge.org is added to your Approved Personal Document E-mail List under your Personal Document Settings on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part of your Kindle email address below. Find out more about saving to your Kindle.

Note you can select to save to either the @free.kindle.com or @kindle.com variations. ‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi. ‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.

Find out more about the Kindle Personal Document Service.

A comparison among equations to characterize lactation curves in beef cows
Available formats
×

Save article to Dropbox

To save this article to your Dropbox account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you used this feature, you will be asked to authorise Cambridge Core to connect with your Dropbox account. Find out more about saving content to Dropbox.

A comparison among equations to characterize lactation curves in beef cows
Available formats
×

Save article to Google Drive

To save this article to your Google Drive account, please select one or more formats and confirm that you agree to abide by our usage policies. If this is the first time you used this feature, you will be asked to authorise Cambridge Core to connect with your Google Drive account. Find out more about saving content to Google Drive.

A comparison among equations to characterize lactation curves in beef cows
Available formats
×
×

Reply to: Submit a response

Please enter your response.

Your details

Please enter a valid email address.

Conflicting interests

Do you have any conflicting interests? *