Browsing by Author "Dougall, H.W."
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Item The Apparent Digestibility of the Non-nitrogenous Fraction of Pig Feeds(1962) Dougall, H.W.; Glover, J.; East African Agriculture and Forestry Research Organization: Kenya, Grassland Research StationA simple method for the estimation of the digestible non-nitrogenous fraction of normal pig feeds is described. It requires only knowledge of the digestibility coefficient of the crude protein contained in the dry matter of the feed. More accurate estimates can be obtained by applying to this method a simple correction involving only the crude protein content of the dried feed. Attention is drawn to the intimacy of the relationship between the digestibility of the non-nitrogenous and nitrogenous components of the diet.Item Average Nutritive Values of Kenya Feeding Stuffs for Pigs(1960/1961) Dougall, H.W.; The Grassland Research StationGlover and Dougall [1] give a Table of average estimates of the percentage of digestible crude protein (DCP) and total digestible nutrients (TON) to be expected from pig feeds ranging in crude protein (CP) content from0-30 per cent of the dry matter and in crude fibre (CF) content from 0-15 per cent of the dry matter. This Table has been used to obtain estimates of the nutritive value of feeds actually grown or processed in Kenya and analysed in this laboratory. Descriptions of the individual feeds and estimates of their nutritive value for pigs, expressed in terms of dry matter (OM), are given in the accompanying Table. The actual amount of dry matter contained in most of the succulents, two of the milk products and the sugar cane molasses is reported alongside the description of these feeds. Similarly where the oil content of a feed exceeds 10 per cent of the dry matter, the actual amount of oil contained in its dry matter is reported alongside the description of the feed, e.g. coconut meal (41.5 per cent oil). Different factors have been used to convert per cent nitrogen to per cent crude protein depending on the description of the feed. It is not the purpose of this paper to discuss in detail minerals in relation to pig rations. None the less it is important to appreciate that if the required amounts of elements such as calcium, phosphorus, chlorine, etc., cannot be obtained from the individual components of rations in amounts that are adequate for growth and development, a supplementary source must be provided. This may take the form of a mixture of finely divided agricultural lime, sodium chloride, etc., in pre-determined proportions and fed as a fixed percentage of the concentrate ration.Item Average Nutritive Values of Kenya Feeding Stuffs for Ruminants(1960/1961) Dougall, H.W.; Grassland Research StationGlover, et al. [1] give a table of average estimates of the percentage of digestible crude protein and total digestible nutrients to be expected from ruminant feeds ranging in crude protein content from 0-42 per cent and in crude fibre content from 5-45 per cent of the dry matter. It can be used for the computation of rations for dairy cows and other ruminants, according to the system of rationing recommended by Morrison [2], or Woodman [3], or according to Forbes' [4] concept of regarding rations as "wholes".Item Browse plants of Kenya with special reference to those occurring in South Baringo(1958) Bogdan, A.V.; Dougall, H.W.; Department of Agriculture"It is a humbling fact for grass pasture experts to realize that probably more animals feed on shrubs and trees, or on associations in which shrubs and trees play an Important part, than on true grass or grass-legume pastures, short and tall grass ranges and steppes." This introductory sentence to "The Use and Misuse of Shrubs and Trees as Fodder" (1947) is almost certainly applicable to most semi-arid and arid parts of Kenya inhabited by pastoral trites and their livestock; it is particularly relevant to the South Baringo District, where most of the material described in this paper was collected. The southern part of the Baringo District is believed to be potential perennial grass-woodland country, but at the present time the grass cover is almost completely destroyed and the ground is exposed to such an extent that even during rainy seasons the leaves, bark and pods of trees and shrubs, together with the available herbs, provide the bulk of the diet of the ruminant and of other livestock.Item Common Acacias of Kenya(1958) Brenan, J.P.M.; Edmondson, R.N.; Koros, S.L.; Dougall, H.W.; Bogdan, A.V.; Thomas, D.B.A number of species of Acacia are very prominent in the woody vegetation of Kenya, and these cover large areas either in pure stands or in mixture with other shrubs and trees. Some of them form thickets and either make grazing impossible or greatly reduce the grazing capacity of land. There are also some useful species which have edible pods and leaves. Forty-three species .of Acacia have been recorded in Kenya. As this pamphlet is mainly intended for the use of those engaged in bush control and pasture management, only the twenty-four commonest species are described and included in the key, thus making the use of the key easy. The remaining species are just mentioned in the index. The botanical names of our acacias are taken from the Flora of Tropical East Africa, Leguminosae, subfamily Mimosoideae, by J. P. M. Brenan, published in 1959, and wrong names that were previously used for some species have now been corrected. The local names are after E. Battiscombe, R. N. Edmondson, S. L. Koros, D. J. Pratt, and D. B. Thomas. Information on the reaction to arboricides is based mainly on a summary by G. W. Ivens in Tropical Agriculture, Vol. 35, 1958, and information on the chemical composition is from "Browse Plants of Kenya" by H. W. Dougall and A. V. Bogdan, East African Agricultural Journal, April, 1958.Item The Gross Energy Content of Some Kenya Feeds(1960) Dougall, H.W.; Grassland Research Station, Department of Agriculture, KitaleWhen the value of a feeding stuff is to be assessed from the standpoint of its value for heat production, the first step in such an evaluation is to measure the gross amount of heat which the organic components of that feed can produce when completely burned. The necessary measurements are obtained by the use of a bomb calorimeter.Item On the Estimation of Crude Fibre in Fodders and Concentrates(1958) Dougall, H.W.; Grassland Research Station, Department of Agriculture, KenyaIt is apparent from the study that the crude fibre content of a fodder may be affected significantly by its state of subdivision and by the procedure used for filtering the acid digest.Any departure from the standard procedure described in the Fertilizers and Feeding-Stuffs Regulations for filtering the acid digest, such as that of filtering through cloth, would seem permissible only if the retentiveness of that cloth is known not to differ significantly from that of filter paper. The United States filter cloth, and one of the Terylenes (A) would conform to this requirement; the linen most certainly would not.Item Silica Distribution in Kenya Roughages(1963) Dougall, H.W.Silica has an almost universal occurrence in plants [1]. It has been found in this laboratory that whereas silica composes on average some7 per cent of the ash of lucerne (Medicagosativa) as this legume grows to maturation in the field, it composes on average over 17, 23,32, 37, 47 and 50 per cent respectively of the ash of Setaria sphacelata, Brachiaria ruziziensis,Cynodon dactylon, Chloris gayana,Melinis minutiflora and Hyparrhenia dissolutaas these grasses grow to maturation under similar circumstances. It has also been found in this laboratory that silica composes over 45per cent of the ash of the whole plant of barley and over 31 per cent of the whole plant of wheat as the two cereals grow to maturation in the field and that it composes over 32 and over 41 per cent respectively of the ash of the"heads" of barley and wheat from the time of their emergence to the time of ripening of the grain. The silica content of the dry matter of the whole barley plant increased from 1.1 percent in the young tissues to over 2 per cent at maturity and that of the whole wheat plant increased from just under 2 per cent to over6 per cent of the dry matter during the same period. The increase in the silica content of the dry matter of the whole wheat plant was directly and highly significantly related to the percentage of dry matter contained in the plant.Item A Table of Estimates of Nutritive Values of Pic Feeds(1960/1961) Glover, J.; Dougall, H.W.; East African Agriculture and Forestry Research Organization (EAAFRO) ; The Grassland Research StationGlover and Dougall [1] have recently shown how average estimates of the nutritive value of feeds for pigs can be obtained from knowledge of the crude protein (CP) and crude fibre (CF) contained in the dry matter of feeds. These values are expressed in terms of digestible crude protein (DCP) and total digestible nutrients (TDN). The estimates of DCP and TDN corresponding to levels of crude protein between 2 per cent and 30 percent and of crude fibre between 0 and 15 percent of the dry matter are given in the accompanying Table I.Item The Total Digestible Nutrients and Gross Digestible Energy of Ruminant Feeds(1960) Glover, J.; Duthie, D.W.; Dougall, H.W.; East African Agriculture and Forestry Research Organization, Muguga, Kenya. Grassland Research Station, Kitale, KenyaIt is shown that reasonable estimates of the average amounts of total digestible nutrients and gross digestible energy of ruminant feeds can be derived from knowledge of only the crude-protein and crude-fibre contents of such material as fed. These estimates do not appear to be markedly affected, if at all, by differences in class of feed or species of ruminant whether cattle, sheep or goat. A table of the average estimates of digestible crude protein and total digestible nutrients, to be expected at different levels of crude protein and crude fibre, is presented for use in the estimation of the average nutritive value of feeds whose digestibility has not been studied in detail by means of numerous animal trials. Inherent in the relationship between either total digestible nutrients or gross digestible energy and the proximate partial composition of the feed is a suggestion that if a low plane of protein nutrition is prolonged, that is when the crude protein of the dry diet lies persistently below some 5% in the dry feed, there is likely to be a sharp fall in the total digestibility of the feed.
