Energy allowances and feeding systems for ruminants / Ministry of Agriculture, Fisheries and Food, Department of Agriculture & Fisheries for Scotland, Department of Agriculture for Northern Ireland.

  • Great Britain. Ministry of Agriculture, Fisheries and Food.
Date:
1975
Catalogue details

Licence: Open Government Licence

Credit: Energy allowances and feeding systems for ruminants / Ministry of Agriculture, Fisheries and Food, Department of Agriculture & Fisheries for Scotland, Department of Agriculture for Northern Ireland. Source: Wellcome Collection.

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    SECTION IV Use of the Metabolisable Energy System for sheep Pregnant and Lactating Animals The use of the metabolisable energy system for pregnant and lactating sheep is similar to that for dairy cows. Maintenance and production require- ments are calculated separately and then summed to give the total require- ment. METABOLISABLE ENERGY ALLOWANCES FOR MAINTENANCE The minimum requirement for energy for maintenance is equal to the fasting metabolism (FM) which may be calculated as follows: FM (M3J/day) = 0.23 W%73 The efficiency of utilisation of metabolisable energy for maintenance (km) for sheep has been taken as being constant at 0.70. For rapid calculation a linear relationship between the metabolisable energy requirement and liveweight may be assumed with little error. With the use of the usual 0.05 safety margin, the maintenance allowance for metabolisable energy for ewes kept indoors may be calculated as follows: Mn = 1.4 + 0.09 W (36) An activity allowance of 0.15 of the fasting metabolism would seem to be justified for ewes living outdoors and the net energy requirement for mainten- ance is then Em == U.205) Wo Using km = 0.70 and a 0.05 safety margin, the equation for calculating maintenance allowance for ewes outdoors becomes Mn = 1.8 + 0.1 W (o) Maintenance allowances for ewes of various weights are given in Table 15. METABOLISABLE ENERGY ALLOWANCES FOR PREGNANCY Pregnancy increases total energy requirement, which is needed for two main purposes: 1. To provide the energy stored in the foetus, its associated membranes, and for the growth of uterine tissue, (E,). 2. To allow for the ‘Heat Increment of Gestation’ (HIG). This is the additional output of heat that occurs during pregnancy and results from (a) energy used to synthesize foetal and associated tissues (b) energy needed to maintain the foetus plus the additional maintenance needs of the ewe resulting from the higher basal metabolism associ- ated with pregnancy.