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A model to maximize hay intake when formulating rations for pregnant ewes

Published online by Cambridge University Press:  02 September 2010

Heather D. St C. Neal ,
J. France ,
R. J. Orr  and
T. T. Treacher
Heather D. St C. Neal
Affiliation:
Grassland Research Institute, Hurley, Maidenhead, Berkshire SL6 5LR
J. France
Affiliation:
Grassland Research Institute, Hurley, Maidenhead, Berkshire SL6 5LR
R. J. Orr
Affiliation:
Grassland Research Institute, Hurley, Maidenhead, Berkshire SL6 5LR
T. T. Treacher
Affiliation:
Grassland Research Institute, Hurley, Maidenhead, Berkshire SL6 5LR
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Abstract

A model is described, which maximizes hay intake in the formulation of rations for pregnant ewes in the last 6 weeks of pregnancy. A regression of hay intake upon hay digestibility, concentrate level, ewe live weight, number of foetuses carried and week of pregnancy, derived from an experiment on individually-recorded ewes, is used as the intake constraint in a linear programme. This is solved in an interactive program which can be implemented on several makes of microcomputer. The intakes of hay predicted by the model are lower than those reported elsewhere, reflecting the more accurately recorded intakes of the original experiment compared with most other published data. The rations formulated by the model show that in weeks 16 to 18 of pregnancy hay could provide most of the ewes' requirements and especially when hays of high metabolizable energy concentration are used. The ease of changing the values of the inputs and the speed of the ration formation enable any number of rations to be formulated quickly for a range of hays and individual conditions.

Type
Research Article
Information
Animal Production , Volume 40 , Issue 1 , February 1985 , pp. 93 - 100
Copyright
Copyright © British Society of Animal Science 1985

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References

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