Browsing by Author "Ledger, H.P."
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Item Animal Husbandry Research and Wildlife in East Africa(1962) Ledger, H.P.; Animal Husbandry Research Unit: E.A.A.F.R.OIt is only in recent years that there has been an appreciation that the problems of wildlife and domestic animal husbandry are complementary and form an integral part of the overall problem of land use. To investigate the meat production potential of East African ruminants a standard form of body and carcase dissection analysis has been devised and is described in detail. It is hoped that a better knowledge of the physiological adaption to their environment of some of the wild species may help to indicate methods of improving animal husbandry in the dry tropics. The data obtained during the course of these investigations will also provide information as to the meat production potential of the individual species. The lines of thought engendered by these investigations are discussed.Item Body composition as a basis for a comparative study of some East African mammals(1968) Ledger, H.P.; East African Agriculture and Forestry Research OrganizationA brief description is given of the standard dissection techniques and recording methods used at E.A.A.F.R.O. to carry out a survey of the body and carcass composition of wild and domesticated stock indigenous to East Africa. Primarily designed to establish the relative meat production potential of animal species the scope of this survey has grown considerably since its inception, and the data obtained can help to clarify ideas and assist in establishing priorities for more detailed research. It is pointed out that research on the effects of environment on animal productivity is of fundamental importance to the evolution of improved animal selection and management practices.Item The Deep-Litter System(1954) French, M.H.; Ledger, H.P.; Joint Animal Industry Division of E.A.A.F.R.O. and E.A.V.R.O.Some form of intensive management is necessary if maximum results are to be obtained from commercial egg-producing units, because intensification makes it easier both to maintain suitable conditions for the birds and to reduce labour hours by the full exploitation of labour-saving equipment. Admittedly, extensive range systems are a useful means of distributing manure and probably permit the maintenance of a healthier flock, but they are more exposed to thieves and vermin and are relatively more costly in the time required for egg collection, feeding and supervision. In all systems of poultry management, personal supervision is essential, and this is more easily achieved under intensive conditions. Even when the size of the unit does not justify the employment of a trained supervisor, it is better to keep lots of 50 to 500 birds on an intensive system and to design the lay-out so that future' expansion can be undertaken easily.Item The Economic Background to the Stall-feeding of Beef Cattle in East Africa(1965) Ledger, H.P.; McQueen, M.; Frank, P.; East African Agriculture and Forestry Research Organization; Kenya Department of Veterinary ServicesThe possibility of stall feeding cattle to provide first-quality export carcasses with which to earn foreign exchange is currently of considerable interest to East African Governments. It is the subject of a joint research programme, between the Kenya Department of Veterinary Services and the Animal Husbandry Division of E.A.A.F.R.O. now being carried on at Muguga.Item The Effects of Hexoestrol Implantation on Carcass Analysis, Energy Balance and Nitrogen Retention of Cattle(1970) Rogerson, A.; Ledger, H.P.; E.A.V.R.O., Muguga, P.O. Box Kabete, Kenya; E.A.A.F.R.O., P.O. Box 30148, Nairobi KenyaSeven pairs of indentical twin steers were used, one animal of each pair acting as the control to its treated counterpart; the selection of these steers was based initially on their phenotypic similarity and was subsequently confirmed by blood tests. Each treated steer was implanted, in the ear, with four 15 mg. pellets of hexoestrol. All the animals were from two to three and a half years old and weighed between 320 and 450 kg at the start of• the experiments. A brief description of these animals is given in Table I. The rations were designed to provide a range of energy intakes from near maintenance (M) to approximately 2M and were based on AR C. standards; they were composed of varying proportions of hay, barley meal, meat meal and dairy cubes. Protein intake was also varied. The animals were weighed daily throughout the experiments which lasted from 90 to 120 days. Water was available at all times and the quantity consumed was measured. Mineral licks were provided for each animal and the amount eaten was recorded. All the animals were kept under uniform conditions in individual pens for the duration of• the experiments, except for their periodic visits to the respiration chamber, where they were confined for 24 hours. During this time• the oxygen consumption, carbon dioxide output and methane production of each animal was determined. All the calorimetric measurements were conducted at 22 C+ 10 and at 60 per cent+ 5 per cent relative humidity. The energy nitrogen and carbon balances of each of the 14 animals were measured on several days during the course of each experiment and the data reported in Table II-are averages of these separate determinations. The type of chamber used and a brief description of the experimental routine were given in an earlier paper (Rogerson, 1960). It should be noted that the animals had been handled frequently from weaning age and had been accustomed to the respiration chamber prior to the commencement of these experiments.Item An Examination of Sample Joint Dissection and Specific Gravity Techniques for Assessing the Carcass Composition of Steers Slaughtered in Commercial Abattoirs(1973) Ledger, H.P.; Gilliver, B.; Robb, J.M.; East African Agriculture and Forestry Research Organization, Muguga, Kenya. U.N.D.P./F.A.O. Kenya Beef Industry Development Project, Lanet.The relationships between joint and carcass specific gravities and composition are examined and the prediction efficiency of equations relating these parameters tabulated. The problems of assessing carcass composition in large abattoirs are indicated. The use of the tenth rib sample joint in conjunction with a specific gravity estimation technique is recommended.Item Food intake and live-weight gain comparisons of Bos indicus and Bos taurus steers on a high plane of nutrition(1968) Ledger, H.P.; Rogerson, A.; Freeman, G.H.; East African Veterinary Research Organization; East African Agriculture and Forestry Research OrganizationA widespread assumption of people engaged in animal production in East Africa is that exotic cattle are best suited to conditions of good nutrition, coupled with absence of any climatic stress, while the indigenous animal can manage better in poor nutritional circumstances and under conditions of considerable stress. Studies such as those carried out by French (1940) and by Phillips, Hungate, MacGregor and Hungate (1960), were designed to see if, in fact, there were differences in digestive efficiency and rate of passage of gut contents between these two types of cattle which could, in some measure, account for the supposed superiority of the indigenous animal under difficult circumstances.Item An Investigation of the Development of “Quality” Traits in Boran, Bos indicus, Steer Carcasses.(1966) Ledger, H.P.; Meat Research Unit, Animal Husbandry Division, East African Agriculture and Forestry Research OrganizationThe production of high priced carcasses has become associated with the production of fast growing muscular tissue (lean meat) combined, in the final product with the desired proportion of carcass fat. A survey of the literature (Callow 1961, Barton 1959, Ledger 1960) together with information obtained from unpublished grading data, suggests the optimum level of fatness for current tastes is about 28 per cent. As fat is the last of the carcass tissues to be laid down, the time taken to reach this degree of fatness can be used as an index of the rate of maturity for quality carcasses. Because it is economically desirable to produce as great a weight as possible of muscular tissue before the animal becomes over-mature (over-fat) it follows that a good beef producer should be a fast growing but slow maturing (fattening) animal. However, the gross weight of fast grown lean in a carcass of the desired degree of fatness is not the only criterion of carcass worth. Equally important is the distribution of that lean throughout the carcass, for it is clearly advantageous to have a higher proportion of this component in the more expensive joints. On the basis that the above is a reasonable summary of the more important traits involved in the production of high quality carcasses it is proposed to illustrate the part played by them in three herds of Boran, Bos indicus steers considered to represent the first three stages of development from primitive husbandry. These stages of" basic"," intermediate" and" improved" production as they relate to East African beef ranching are described as follows:—(a) Basic production refers to the purchase of immature stock from tribesmen in the extensive, arid" bush" areas for ranch-fattening on grass. In practice these" immatures" are usually between 21 and 3 years old at the time of purchase and are seldom slaughtered before they are four.Item A Method of Predicting Liveweight from Dissected Leg Weight(1965) Smith, N.S.; Ledger, H.P.; Washington State University. East African Agriculture and Forestry Research Organization, Muguga, Kenya.Ledger (1964) observed that leg weight was a constant of liveweight for 40 Brahma steers regardless of age or degree of fatness, and this paper reports on the liveweight/leg weight relationship for 248 African wild ungulates and 75 boran cattle, suggesting that this constant be used as a method of estimating liveweight. The correlation coefficients, leg weight as a percentage of liveweight, and standard deviations are given for each species. The data indicate that the weight of either foreleg or hindleg as a percentage of liveweight is constant and little affected by either sex, age, or degree of fatness for the nine species examined.Item A Portable Tripod and Weighing Assembly for Large Animals(1965) Norman, S.S.; Ledger, H.P.While conducting a survey of carcass and body composition analyses of East African Ungulates, we found it necessary to devise a method of weighing large animals in the fieldItem Utilization of Coffee Hulls in Cattle Fattening Rations(1972) Ledger, H.P.; Tillman, A.D.; E.A.A.F.R.O., MugugaIn East Africa the supplementary feeding of beef cattle to provide quality carcasses is currently receiving considerable attention. Whilst there is no difficulty in compounding suitable rations to provide the necessary nutrients for this purpose the narrow profit mar- gin for beef and the seasonal fluctuations in the price and availability of the most suitable feed components make it necessary to investigate the use of alternative feeds for economic production. Tillman et al. (1969) found that rice hulls, although only rating as a low-quality rough age, when included in a high-grain ration materially decreased the cost of a ration without reducing its productive efficiency. Rogerson (1955) found that coffee hulls, also a low-quality roughage were palatable to sheep. Because coffee hulls, a by-product of the coffee industry, are readily available in many parts of East Africa the value of their use in a cattle fattening ration similar to that in which rice hulls were used has been investigated.Item The value of the tenth rib as a sample joint for the estimation of lean, fat and bone in carcasses of East African zebu cattle(1962) Hutchison, H.G.; Ledger, H.P.; Livestock Research Division, Veterinary Division: Ministry of Agriculture and Co· operative Development, Tanganyika1. Studies of tissues distribution in beef carcasses of East African 'Boran' cattle revealed very high correlations between the separable tissue analysis of the full tenth rib sample joint and of the full side. 2. A comparative study of tenth rib sample joints, from twelve steers and five cows cut at various positions along the length of the rib showed that the full rib sample gave a higher correlation (r = 0•948), with the full side in respect of all tissues except the subcutaneous fat, than any other sample joint. The subcutaneous fat of the whole side could not be predicted with reliability by the use of any rib sample, the highest correlation (r = O• 558) existing between the half-rib sample and the full side. 3. From detailed carcass studies of thirty-two steers and eight cows, including the twelve steers and five cows mentioned above, prediction equations are presented for estimating the percentages of lean, total fat, and butchers' bone in whole carcasses from single complete tenth rib samples. Standard deviations being 1•53 % for lean, 1•34 % for total fat in steers, 1•13 % for total fat in cows and 0•88 % for butchers' bone.
