Browsing by Author "Maloiy, G.M.O."
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Item Allometry of the Legs of Running Birds(1979) Maloiy, G.M.O.; Alexander, R.M.; Njau, R.; Jayes, A.S.; University of Nairobi, P.O. Box 30197, Nairobi, Kenya. University of Leeds, Leeds EnglandThe principal bones, muscles and tendons of the legs have been measured in a selection of running birds, ranging in size from 0–1 kg quail to 40 kg ostrich. Maximum stride frequencies of the same species have been determined from films. Allometric equations have been derived. Most of the exponents agree well with McMahon's (1973, 1975a) theory of elastic similarity, which is discussed.Item Digestion and Nitrogen Metabolism in Sheep and Red Deer Given Large or Small Amounts of Water and Protein(1970) Maloiy, G.M.O.; Kay, R.N.B.; Goodall, E.D.; Topps, J.H.; Rowett Research Institute, Bucksburn, Aberdeen AB2 9SB; School of Agriculture, University of AberdeenThe interaction between intakes of water and N was studied in 2 ewes and 2 red deer hinds. They were given pelleted diets, at maintenance level, containing equal amounts of roughage but rich or poor in N. The deer were given 50% more feed than the sheep. Water was given either in large amounts, 5.0 litres for sheep and 7 0 for deer, daily or in small amounts 1 1 and 2.4 litres. Nearly three-quarters of the N of the high-N rations but less than half of that of the low-N rations was excreted in urine. Restriction of water reduced excretion of N in urine by only about 1 g daily, mainly as a result of decreases in urea and ammonia, but did not affect the excretion of N in faeces. Excretion of creatinine, creatine, hippuric acid, uric acid and allantoin in urine was examined also. Excretion of creatinine was not related to intake of N or water. Excretion of uric acid and of allantoin was greater in sheep than in deer. Concentrations of urea in plasma and of ammonia in rumen fluid were measured before and after feeding. Plasma urea was related to intake of N and was more on the smaller intake of water. Rumen ammonia also was related to intake of N but, while it generally increased after feeding when more N was given, it fell almost to zero 2 h after feeding when less was given. The sheep digested DM, cellulose and N a little more fully than the deer. The high-water regime slightly increased digestibility of DM and cellulose but did not affect digestibility of N.Item The Effect of Dehydration and Heat Stress on Intake and Digestion of Food in the Somali Donkey(1973) Maloiy, G.M.O.; East African Veterinary Research Organization, Muguga, Kabete, KenyaThe changes in intestinal digestion of the Somali donkey due to both a simulated desert environment (exposure for 12 hours at 22 deg C (dry bulb) and 18 deg C (wet bulb), followed by a further 12-hour period of exposure to a temperature of 40 deg C (dry bulb) and 24 deg C (wet bulb), and to a stress condition consisting of a water restriction up to a 15% level of dehydration, with and without heat load, were investigated. Dehydration at both environmental temperatures (22 deg C and 22-40 deg C), separately, depressed food intake and increased apparent digestibility of dry matter, but an intermittent heat load as found in the desert environment had no effect by itself on either value. This suggests that the donkey can graze in the heat when water is available.Item The Effect of Dehydration and Heat Stress On Intake and Digestion of Food in the Somali Donkey(1973) Maloiy, G.M.O.; East African Veterinary Research Organization, Muguga, Kabete, KenyaThe changes in intestinal digestion of the Somali donkey due to both a simulated desert environment (exposure for 12 hours at 22 deg C (dry bulb) and 18 deg C (wet bulb), followed by a further 12-hour period of exposure to a temperature of 40 deg C (dry bulb) and 24 deg C (wet bulb), and to a stress condition consisting of a water restriction up to a 15% level of dehydration, with and without heat load, were investigated. Dehydration at both environmental temperatures (22 deg C and 22-40 deg C), separately, depressed food intake and increased apparent digestibility of dry matter, but an intermittent heat load as found in the desert environment had no effect by itself on either value. This suggests that the donkey can graze in the heat when water is available.Item The Effects of Dehydration and Heat Stress on Intake and Digestion of Food in Some East African Bovids(1967) Taylor, C.R.; Maloiy, G.M.O.; East African Veterinary Research Organization, MugugaThe effect of (a) an intermittent heat load (a daily cycle of 12 hours at 22°C and 12 hours at 40°C) and (b) a 15% level of dehydration, with and without the heat load, on food intake and digestibility of a poor-quality hay was investigated in the arid Grant's gazelle and oryx; the arid domestic Turkana goats, fat-tailed sheep and zebu cattle, and the non-arid Thom- son's gazelle and wildebeest. An intermittent heat load with water available ad libitum depressed the food intake of zebu cattle and Turkana goats more than 40%. It had no significant effect on intake of any of the other species. Dehydration at 22°C caused a marked depression in food intake of all the species investigated. Dehydration together with a heat load caused no further reduction in food intake of the arid Grant's gazelle and oryx, or in goats but did cause a further reduction in the other species. The digestibility of food by the Thomson's and Grant's gazelle is found to be much higher than that of any of the other species.Item Response of the Somali Donkey to Dehydration: hematological Changes(1971) Maloiy, G.M.O.; Boarer, C.D.H.; E.A.V.R.O., Muguga, Kabete, KenyaAdult donkeys, 3 male and 2 female weighing 130 to 180 kg, and 3 zebu bullocks weighing 230 to 300 kg were given hay and water to appetite for 14 days, completely deprived of water for 3 to 5 days at 22° to 40°C and then given tap water at 20°. In addition one donkey was deprived of drinking water at 22o for 24 days and given poor hay to appetite. In the dehydrated animals plasma osmolarity, Na, C1, Hb, packed cell volume, red blood cells and plasma proteins increased. Dehydration caused plasma proteins to increase by 30 to 51% and plasma volume by 6 to 14% in the donkeys. Neither dehydration nor rehydration had any observable effect on mean cell Hb which was 22 pg for the donkey and 16 pg for the zebu. The bodyweight of the donkey deprived of water for 24 days dropped from an initial 148 to 102 kg. Its plasma protein increased from 7.0g to 11.6g/100 ml and plasma volume by 14%. On day 25 the donkey drank up to 38 litres of water in 8 min; its weight increased to 138 kg and by the 3rd day to 146 kg when blood values returned to normal. In the dehydrated donkeys mean cell volume and intracellular and extracellular water fell. Plasma volume was reduced from 9.6 to 6.2 litres. Most of the blood values returned to normal within 24 h after water intake. In the zebus there was little or no change in mean cell volume and Hb concentration from dehydration, but loss of bodyweight was more than in the donkey.-B. A. O.Item Sweat gland function In the red deer (Cervus elaphus)(1972) Johnson, K.G.; Maloiy, G.M.O.; Bligh, J.JOHNSON, K. G, G. M. O. MALOIY, AND J BLIGH. Sweat gland function in the red deer (Cmus elaphus). Am. J. Physiol. 223(3): 604- 607. 1972.-Sweating has been studied in two male red deer Exposure to 20/16 C (DB/WB) or 40/26 C T, elicited smail, intermittent sweat discharges occurring synchronously over the trunk but only a low or negligible rate of continuous sweating. During 2-3 hr at 45/28 eTa, animals reached a stable Tre, with respiratory frequencies of 200/min or more and rate~ of cutaneous moisture evaporation slightly more than could be attributed to passive water vapor diffusion. Intravenous injections of adrenaline (0.2!-Ig•kg-I body wt or more) elicited dose-dependent discharges of sweat from the trunk. Intravenous noradrenaline was less effective as a stimulus to sweating, and isoprenaline was ineffective. Intravenous infusions of adrenaline (8.3-33.3 ng' kg-I. sec-I) elicited initial large discharges of sweat which declined while the infusions were maintained. Adrenaline-induced discharges of sweat were largely blocked by phenoxybenzamine but not by propranolol. Antler "velvet" did not discharge sweat nor contain sweat glands. The sweat glands in the trunk skin of red deer are functional, and sweating probably contributes to evaporative cooling during exposure to high T a.)Item Temperature Regulation in the Somali Donkey (Equus Asinus)(1971) Maloiy, G.M.O.; East African Veterinary Research Organization, Muguga, Kabete, Kenya, East AfricaIn controlled laboratory experiments the metabolic rate, body temperature, respiratory, sweat and heart rates were measured in adult donkeys weighing between 125 and 180 kg.At high ambient temperatures Ta (40–50°C) the sweating rate rose to 145 g H2O/m2 per hr and the respiratory rate to approximately 130/min. In cool conditions (10°C) the metabolic rate rose to approximately 5 ml oxygen/kg per min from a value in thermal neutrality (22–32°C) of 4 ml/kg per min. Between ambient temperatures of 5 and 50°C the rectal temperature Tr ranged from 35 to 39°C.Item Water economy of the Somali Donkey(1970) Maloiy, G.M.O.; Animal Physiolagy Division: East African Veterinary Research OrganizationMaloiy, G. M. Water economy of the Somalii Donkey, American Journal of Physiology 219(5): 1522- 1527. 1970. Water balance, blood intake, volume and concentration of urine and changes in the body weight were examined in the Somali donkey subjected to heat stress and dehydration. The effects of an ambient temperature of 22C or changes between 22 and 40C at 12-hr intervals and a level of dehydration causing 15% loss of body weight at each of these temperatures on food intake and digestion were investigated......Item Water Economy of the Somali Donkey(1970) Maloiy, G.M.O.; East African Veterinary Research Organization, Muguga, Kabete, Kenya, East AfricaWater balance, food intake, volume, and concentration of urine and changes in body weight were examined in the Somali donkey subjected to heat stress and dehydration. The effects of an ambient temperature of 22 C or changes between 22 and 40 C at 12-hr intervals and a level of dehydration causing 15% loss of body weight at each of these temperatures on food intake and digestion were investigated. Dehydration at each environmental temperature depressed food intake and increased apparent digestibility of dry matter, but a periodic heat load without dehydration had no effect on either parameter. The animal's appetite failed altogether when 20-22% of its initial body weight had been lost. Fecal and evaporative routes were the main avenues of water loss in all experimental conditions. Evaporative water loss was reduced by 65 and 52%, respectively, when animals were dehydrated at 22 and 22-40 C. The donkey can survive a loss of water corresponding to 30% of its original body weight even at an ambient temperature of 40 С, and can drink in 2-5 min enough water (24-30 liters) to restore its deficit. Even when water was freely available, urine volume was low (0.7-1.2 liters/day). The donkey's kidney was not able to excrete a highly concentrated urine; 1,440-1,545 mOsm/kg H₂O was the maximum osmolality, with urea contributing 300-410 mu. When the donkey was offered various concentrations of NaCl solution as its sole source of drinking water, the maximum level accepted by the animal was 0.75-1.00% NaCl.Item The Water Metabolism of a Small East African Antelope: The Dik-Dik(1973) Maloiy, G.M.O.; East African Veterinary Research Organization, Muguga, Kabete, and Department of Animal Physiology, University of Nairobi, KenyaIn controlled laboratory experiments, rectal temperature, cutaneous moisture evapora¬tion, and respiratory rate were studied in the dik-dik. The water balance of the dik-dik was investigated when the antelope were either fully hydrated or dehydrated at the environ¬mental temperature of 22 °C or at temperatures alternating between 22 °C and 40 °C at 12 h intervals. Faecal, urinary and evaporative water losses were all reduced by varying degrees during dehydration at 22 °C and 22 to 40 °C. The highest urine osmolality recorded was 4318 ± 105 mosmol/kg H2O which occurred when the antelopes were severely dehydrated. At the high air temperatures (40 to 45 °C) cutaneous evaporation measured with a non-ventilated sweat capsule was 19 g H2O m-2 h-1 and the respiratory rate over 360/min. Thus, the respiratory tract seems to be the major avenue for dissipating excess heat in dik-dik exposed to thermal stress. Injection of adrenaline, intravenously, stimulated sweat dis¬charges similar to those observed in the small gazelles, and sheep and goats. The low-water exchange and an efficient kidney helps explain the ability of this small antelope to inhabit hot arid areas.
