Parnell, Ivan William

2019-02-15T14:15:53Z

2019-02-15T14:15:53Z

1932

GENERAI,: Available evidence seems to show that the Scottish Blackface breed is not an indigenous breed of sheep in Scotland. It has been introduced from the south and has spread northwards. The breed has never become successfully established in Caithness and Sutherland: otherwise it has become the most numerous and important breed in the remaining mountain- ous parts of the country. It is probable that its characters have been influenced by crossing with the native "dun" - or with the. "white-faced" sheep and the infusion of this and possibly other blood may explain in part the differing characters in various districts. FLEECE CHARACTERS: The character of the fleece varies in diftferent districts in Scotland: so much so that definite areas are associated with the production of various grades of Blackface wool required for tweeds, carpets mattresses and so on. The reasons for the difference between the fleeces of these districts are not obvious it is suggested however that there may be some areas where a larger amount of unimproved blood enters into the compositon of the sheep stocks than elsewhere and that parasitic infestation and variation in the mineral and other content of the pasture may collectively or individually play a large part in this differentiation. Climatic conditions per se do not appear to exert that considerable influence on fleece which is usually attributed to them. CROSSING: The results of crossing with modern breeds of sheep has been considered and it seems evident that some of the characters are sex -linked, (for example the fleece characters of the Blackface x Gritstone.) Of the other crosses that with the Merino appears to be of the greatest interest, since increased density of fleece could still be demonstrated in the fourth generation of back- crossing to the Blackface. In practically all crosses rams of other breeds have been crossed with Blackface ewes. Crossing with Border Leicesters and Wensleydale are important commercial crosses, producing sheep, specially useful for the butcher. FACE COLOUR: The relationship between face-colour and various other factors has been considered, mainly from data accumulated on the writer's own farm in Perthshire during the past ten years. These results indicate that breeders can, by selection of their stock, with due regard to face colour, improve commercially important points. Sufficient data has been collected to show that by selection of the parents for face colours, a considerable proportion of the progeny will have those colours which this work has shown to be desirable, i.e. the extremes of face colour both black and white in ewes have been shown to be associated with lambs of inferior size and dead weights. That the face colour of the sire is important because it is shown that different colours are c-o,rrelat.ed with different decrees of hardiness in his lambs. It has been demonstrated that blackspotting in the fleece can be materially improved by using sires free from this fault and that black spotting and face colour are correlated. FERTILITY. It is shown that under a constant environment bath high and low fertility is transmitted from the sire to his daughters and is characteristically exhibited by thee: subsequently. It has not however been possible to test whether females may transmit fertility factors to their sons, and only very limited figures are given to show the influence of rams on their grand - daughters and on their sons, since only a few home -bred rams were used. Evidence is advanced which suggests potential economic importance of the influence of rams on the fertility of a Blackfaced breeding stock; for although the average for barrenness in this flock was 14%, one ram left daughters who were never barren, another ram's daughters only had a figure of 5% for barrenness, but four rams left daughters whose barrenness figures were 22 %, 23%, 24% and 29 %. FLOCK RECORDING: It is very evident that much valuable information on matters intimately concerned with breeding and inheritance under practical conditions is lost through the absence of a general system of marking and flock recording. The experience of marking and recording on which this work is based shows that the advantages gained compensate for the expenditure of such time and money as is involved.

http://hdl.handle.net/1842/33462

The University of Edinburgh

Annexe Thesis Digitisation Project 2019 Block 22

Studies on the Scottish Mountain Blackfaced sheep: with special reference to the inheritance of certain breed characteristics

Thesis or Dissertation

Doctoral

PhD Doctor of Philosophy