Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.657831
Title: The diet and behaviour of hill sheep
Author: Milner, C.
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 1963
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Abstract:
The hill lands of Gt. Britain occupying one third of the agricultural acreage produce only about 4% of the total agricultural output. This same area however produces some 30% of the sheep and sheep products of the country. (Davidson & Wibberley, 1956) The key therefore to the economic stability of agriculture in the hills is the hill sheep, for although an increasing number of cattle are being kept, it is difficult in many areas to overcome the problem of Winter keep. The hill environment is considerably more adverse than that of the lowland and the hill ewe is required to survive the winter on an insufficient diet while satisfying the demands of the foetus at a most critical period of development. (Wallace, 1948) For these reasons the hill ewe has been the subject of various investigations based mainly on supplementation of the meagre winter diet. The basic problem however is the interrelation between the sheep and its pasture. Ewes kept on virtually unrestricted hill grazings are able to exercise considerable choice both of the plant communities and species grazed. Under such conditions the factors that determine the distribution of the ewes over the hill are of considerable importance in determining the environment of the individual ewe. Social and flock behaviour is more evident under the low stocking rates encountered and the conditions may therefore be described as semi-natural. It is with this aspect of hill sheep production that the present thesis is mainly concerned. The diversity of the hill sward, which provides the nutrient requirements of the sheep, imposes on them a diversity of nutritional levels and is therefore likely to be one of the most important environmental factors influencing productivity. The basic problem of hill farming is the efficient utilisation of a semi-natural environment. The animal most frequently used for this purpose is the sheep and it is with sheep and their utilisation of hill pastures that this thesis has been concerned. The heft is a complex ecosystem of several sward types grazed at different intensities and producing varying amounts of animal nutrients. The factors governing the grazing intensity and productivity of various communities are not simply those inherent in the coramunity although these are of some importance. Social factors resulting in a non-random distribution of the sheep over the available pasture have been demonstrated and the importance of the home range of the ewes in determining the home range of the lamb shown. This obviously has a considerable effect on the utilisation of the different communities particularly since up to the present time no account lias been taken of the home range of a ewe and lamb when selecting replacement breeding stock. This has resulted in the selection of lambs from better environments rather than lambs of possibly superior breeding merit. The extent of the environmental difference cannot be accurately determined but sufficient has been produced to show that it is likely to be a very potent source and possibly the most important source of variation in the flock. The chief conclusion of this thesis must be that without prior consideration of the complex factors governing the grazing of hill pastures, improvement is blind and may only be of short term value. The Increased productivity of a hill flock and of a hill sward is essentially an ecological problem and should be treated so. The preliminary results in this thesis are an attempt at a solution of some of the ecological problems involved.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.657831  DOI: Not available
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