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Basic haematological values in antelopes--IV. A comparison and concluding remarks.

Comparison of mean erythrocyte counts, mean haematocrit values, mean haemoglobin content and mean corpuscular volume of the red cell is presented for 21 species of antelopes (four species being excluded because of the small number of animals investigated). A direct relationship of haematocrit values and haemoglobin content and an inverse relationship of red cell counts and mean corpuscular volume of the erythrocytes were noted. The significance of an increased total surface area for oxygen exchange is discussed and values obtained in the red blood picture are compared with those of domesticated animals (cattle, goat and sheep) taken from the literature. Mean leukocyte counts were found to be in the human range with the exception of two species, but significantly lower than in domesticated artiodactylids. Problems in assessing the general health, the age, the effect of diet and of environment in captivity are discussed. Problems of methodology, especially of blood sampling, are given comparing results in manually restrained and in sedated animals.

Animals↗

Thermoregulation and heat balance in the dik-dik antelope (Rhynchotragus kirki): a field and laboratory study.

Experiments were conducted in the field to study the physiological responses of dik-dik antelope to direct solar radiation and shade. The results were compared to those obtained in the laboratory. The rates of metabolic heat production when the animals were exposed either to the sun or the shade were identical. Dik-dik antelopes lost about 50% more heat evaporatively when exposed to the sun compared to the shade at an ambient temperature (Ta) of 28 degrees C or a Ta of 40 degrees C in a climatic chamber. Heat storage in the laboratory at Ta 40 degrees C or at Ta 28 degrees C in the shade accounted for between 30 and 35% of the total heat production. The corresponding value in the sun was 55%. The net rate of heat gain under the sun was four times greater than under shade at 28 degrees C or in the laboratory at 40 degrees C. Behavioural mechanisms for avoidance of high insolation must constitute important adaptations that the dik-dik uses to avoid dehydration and dependence on drinking water in their natural environment.

Animals↗

Physiological responses of the adult male collared peccary, Tayassu tajacu (Tayassuidae), to severe dietary restriction.

Metabolic and hormonal responses of eight adult male collared peccaries (Tayassu tajacu) to an ad libitum diet intake, or 25% of an ad libitum intake, were examined. Blood samples for hematological, serum-biochemical and hormonal profiles were collected at three week intervals during the nine week experiment starting 4 August 1983. Males fed on the restricted diet lost an average of 26% of their body weight during the trial, compared to a slight weight gain for those fed ad libitum. Characteristics of the red and white blood cell populations were not influenced by diet intake, with the exception of mean corpuscular volume, which was consistently lower amongst males fed on the restricted diet. Restricted food intake resulted in significantly elevated serum values for urea nitrogen, urea nitrogen:creatinine, urea index, alpha globulin:beta globulin, gamma globulin:albumin, nonesterified fatty acids, alkaline phosphatase and lactate dehydrogenase isozymes (LD1 and LD2). Restricted food intake resulted in significantly lowered serum values for total alpha globulin, alpha-1 globulin, total beta globulin, beta-1 globulin, beta-2 globulin, glucose, triglycerides, calcium, magnesium, sodium, chloride, copper and triiodothyronine. Serum levels of creatinine, total protein, albumin, alpha-2 globulin, uric acid, total bilirubin, cholesterol, aspartate aminotransferase, alanine aminotransferase, gamma glutamyltransferase, lactate dehydrogenase, phosphorus, calcium:phosphorus, potassium, iron, zinc and thyroxine were unaffected by diet intake level. Semen evaluation indicated spermatogenesis was not affected by dietary restriction despite reductions in scrotal circumference and ejaculate gel volume. Serum testosterone levels were significantly lower among males fed on the restricted diet after nine weeks. These data suggest male libido might be depressed during poor range conditions, while maintenance of spermatogenesis might permit them to take immediate advantage of improved range conditions. Blood analysis of metabolic and hormonal function can provide useful information for predicting the adult male's nutritional and reproductive condition.

Animals↗

Time-dependent influence of some sedating agents on basic haematological values in various artio- and perissodactylids.

Basic haematological values in 32 animals of five species were estimated after administration of sedating agents. In all species under investigation, a time-dependent decrease of erythrocyte counts, haematocrit values and haemoglobin content was noted during the first 30 min after sedation, for the following 30 min the lowered values remained essentially without any change in zebras. Derived parameters, mean corpuscular haemoglobin, mean corpuscular Hb concentration and mean corpuscular volume did not change during the period of observation. Only insignificant changes in leukocyte count and in the proportion of lymphocytes and neutrophiles were registered. The shortest possible time between sedation and blood sampling is recommended to minimalize a distortion especially in the red blood picture.

Animals↗

Does gravitational pressure of blood hinder flow to the brain of the giraffe?

Vascular pressure consists of the sum of two pressures: (a) pressure developed by the pumping of the ventricles against the resistance of vessels, designated as viscous flow pressure, and (b) pressure caused by gravity, traditionally called hydrostatic, better described as gravitational pressure. In a conduit, both of these pressures must be overcome when a liquid is discharged to a higher level of gravitational potential energy. If a liquid is returned to its original level, gravity neither helps nor hinders flow because of the siphon effect. This circumstance prevails in the circulatory system. Hence, P1-P2 in the Poiseuille equation excludes gravitational pressure between those points. The long neck of the giraffe, therefore, poses no impediment to blood flow in the erect posture. The giraffe has a high aortic pressure. This is not for driving the blood to its head but is for minimizing the gravitational drop of intravascular pressure and collapse of the vessels. The cerebral circulation is protected by the cerebrospinal fluid which undergoes parallel changes in pressure with posture. Other vessels in the head are less protected by connective tissue, surrounding muscles and other structures. The high aortic pressure in the giraffe is probably caused by the high total peripheral resistance of the systemic circuit due to vascular adaptations related to the overall height of the animal.

Animals↗

Retention of fluid and particles in the digestive tract of the llama (Lama guanacoe f. glama).

The retention times of fluid and particles of different lengths were measured in the digestive tract of the llama. PEG was used as a fluid marker; hay particles were labelled with cerium or samarium and the samples were determined by neutron activation analysis. In compartments 1 and 2 the retention time of fluid (9.7 hr) was significantly shorter than that of particles having a length of 0.2-1.0 cm (19.2 hr) and 2.5-4.0 cm (25.0 hr). In the intestine slightly significant differences in the retention times of fluid (20.1 hr) and particles (26.2 hr) were seen. In the whole digestive tract retention times were 36.2 hr for fluid, 52.0 hr for smaller particles and 59.9 hr for larger particles.

Animals↗

Changes in nonspecific immunity factor in some Equidae, Camelidae and Capridae species.

Plasma lysozyme activity changed during the 2 years of the investigation period. In some species (e.g. ponies and goats) there are only seasonal fluctuations with the highest levels during summer and autumn in ponies and during winter in goats. In two Camelidae species, guanacos and llamas, only, downward trends were found, whereas in donkeys, both types of changes: seasonal variations with the maximal level during autumn and an upward long-term trend were found.

Animals↗

Renal excretion of urea in a small east African antelope, the dik-dik (Rhynchotragus kirkii).

1. A study on the renal handling of urea by the dik-dik antelope (Rhynchotragus kirkii) was conducted. 2. Plasma and urine samples were analysed for osmolality, urea and creatinine concentrations during dehydration and intra-ruminal loading of potassium and sodium solutions. 3. The glomerular filtration rate (GFR) of the dik-dik was found to be 182.6 +/- 11.7 ml/min/100 kg body mass. 4. Dehydration was observed to increase tubular urea reabsorption and increase plasma and urine osmolalities, but had no effect on the amount of urea filtered at the glomerulus. 5. Potassium loading increased both GFR and urine flow rate.

Animals↗

Tannins and digestibility in the steenbok (Raphicerus campestris).

1. The influence of tannins on the digestion of a small ruminant was investigated. 2. A 1% tannic acid diet was compared with a normal diet. 3. The digestion of protein decreased by 7.04%, fibre by 9.77% and energy utilization decreased by 7.94%. 4. Tannic acid has a marked depressing effect on the digestibility of the steenbok.

Animals↗

Some effects of water deprivation on dorcas gazelle (Gazella dorcas) in the Sudan.

1. The effects of dehydration for 10 days and subsequent rehydration for 2 days on some physiological and biochemical parameters were studied in the Dorcas gazelle. 2. At the end of the 10 days of dehydration, feed intake and body weight were decreased by 42 and 29% of the control values, respectively. Rehydration restored most of the loss in feed intake and body weight. 3. Dehydration decreased the water content in the faeces of the gazelles by 41%. Rehydration restored 36% of the lost faecal water. Urine volume in dehydrated animals decreased by 66%, an effect which was readily reversed by rehydration. 4. Blood haemoglobin of dehydrated gazelles decreased by 22% but this effect was not reversed by rehydration for 2 days. 5. Dehydration for 10 days decreased the concentration of serum glucose by 34% and increased that of urea and albumin by 34 and 18%, respectively. Dehydration for 2 days reversed these effects completely. 6. The serum concentrations of sodium, potassium and chloride were increased by dehydration by 23, 44 and 18% respectively. After 2 days of rehydration the values returned to normal. 7. No change in the heart rate, pulse or temperature was found during the dehydration period. 8. The gazelles survived the 10 days of dehydration, although they tended to be drowsy, weak and emaciated during the last 2 days of dehydration. The animals appeared normal after rehydration.

Animals↗

Physiology of the dik-dik antelope.

1. The East African dik-dik antelope represents a miniature model ruminant for comparative studies. 2. Dik-diks are browsers, consuming a diet consistently high in fermentable and digestable plant material. 3. Their foregut structure is designed for a relatively rapid passage of food and effective absorption of fermentative products. 4. Dik-dik antelopes are very economical in their use of water, having a low daily water exchange and excreting a highly concentrated urine. 5. Dik-diks have been observed to employ three thermoregulatory mechanisms; thermopanting, active sweating and a labile body temperature. 6. Their reproductive cycle is polyestrous with peak breeding in June and December, having a gestation period of between 170 and 174 days.

Animals↗

Levels of T4, T3 and cortisol in the blood serum of the European bison (Bison bonasus) in the winter period.

1. In the blood of 56 European bison, the levels of T4, T3, and the ratio of T3:T4 and cortisol were studied. 2. Between December and March, the T4 level changed from about 53 to 83 ng/ml of blood serum but in April it increased to 90 ng/ml. 3. The level of T3 in this period was 0.817-1.475 ng/ml and in April it was 2.40-3.40 ng/ml. 4. The ratio of T3:T4 was 0.015-0.024 and in April it increased to 0.027-0.052. 5. The level of cortisol changed from 1.00 to 6.70 ng/ml and in April it was from 1.00 to 14.00 ng/ml.

Animals↗

Seasonal changes in the red blood cell system in the European bison, Bison bonasus L.

1. In 195 European bisons divided into four groups (Group 1, 0-3 year-old males; Group 2, 0-3 year-old females; Group 3, mature bulls, over 3 years old; Group 4, mature cows, over 3 years old) seasonal changes in red blood cell number and diameter, haemoglobin level, haematocrit value, index F, MCH, MCHC and MCV were studied. 2. Seasonal cyclicity was found only in red blood cell diameters in all groups. 3. In young males the cyclicity was found in MCHC and in MCV only. 4. In young females the cyclicity was found in Hb and Hct values, in MCH and in MCV. 5. In mature bulls cyclicity was found only in RBC diameter and in MCV. 6. In mature cows the cyclicity was found in index F, MCH and in MCHC values. 7. Seven out of 14 acrophases of cyclic indices occurred just before autumnal equinox and three before vernal equinox.

Animals↗

Seasonal cyclicity in carbohydrate metabolism parameters in the European bison, Bison bonasus L.

1. In 197 European bison divided into four groups (Group 1, 0-3-year-old males; Group 2, 0-3-year-old females; Group 3, mature bulls, over 3 years old; Group 4, mature cows, over 3 years old) seasonal changes in the level of lactic and pyruvic acids, glucose and alkaline reserve were studied. 2. Seasonal cyclicity was found only in lactic acid levels in all groups. 3. In the pyruvic acid level cyclicity was found only in males. 4. In the glucose level cyclicity was found only in mature cows. 5. In alkaline reserve cyclicity was found only in mature bison. 6. Six out of 9 acrophases of cyclic indices occurred in the period from the second half of August until mid-December, i.e. before the winter time.

Alkalies↗

DNA cloning and hybridization in deer species supporting the chromosome field theory.

The Cervidae show the largest variation in chromosome number found within any mammalian family. The eight species of deer which are the subject of this study vary in chromosome number from 2n = 70 to 2n = 6. Three species of Bovidae are also included since they belong to a closely related family. Digestion of nuclear DNAs with the restriction endonucleases Hae III, Hpa II, Msp I, Eco RI, Xba I, Pst I and Bam HI reveals that there is a series of highly repetitive sequences forming similar band patterns in the different species. There are two bands (1100 and 550 base pairs) which are common to all species although the two families separated more than 40 million years ago. To obtain information on the degree of homology among these conserved sequences we isolated a Bam HI restriction fragment of approximately 770 base pairs from red deer DNA. This sequence was 32P labeled and hybridized by the Southern blot technique with DNAs cleaved with Bam HI, Eco RI, Hpa II and Msp I. Moreover, the same sequence was cloned in the plasmid vector pBR322 nick translated with 32P and hybridized with the DNAs of 8 species of Cervidae and 3 of Bovidae. The same cloned probe was labeled with 3H and hybridized in situ with the metaphase chromosomes of red deer (2n = 68) and Muntiacus muntjak (2n = 7 male). Homologies are still present between the highly repetitive sequences of the 8 species of Cervidae despite the drastic reorganization that led to extreme chromosome numbers. Moreover, the cloned DNA sequence was found to occupy the same position, in the proximal regions of the arms, in both red deer (2n = 68) and M. muntjak (2n = 7 male) chromosomes. The ribosomal RNA genes and the centromeres in these species have also maintained their main territory despite the drastic chromosome reorganization. These results are experimental confirmation of the chromosome field theory which predicted that each DNA sequence has an optimal territory within the centromere-telomere field and tends to occupy this same territory following chromosome reorganization.

Animals↗

Sarcocystis sp. in guanaco (Lama guanicoe) and effect of temperature on its viability.

The biology of the Sarcocystis sp. that infect guanacoes was studied by feeding the infected meat to dogs, cats, rats and mice. Tissues from guanaco, heavily infected with macrocysts, were fed to these animals and their faeces collected daily and examined for the presence or absence of sporocysts. It was shown that only dogs were suitable definitive hosts. The effect of cooking and freezing on the viability of this protozoan organism was also investigated. Freezing to -18 degrees C and -24 degrees C and cooking were effective for inactivating Sarcocystis in guanaco meat. These methods could therefore be used instead of condemning guanaco carcasses infected with Sarcocystis.

Animals↗

Studies on ticks of veterinary importance in Nigeria. XI. Observations on the biology of ticks detached from the red-flanked duiker (Cephamophys rufulatus) and parasites encountered in their blood.

Some aspects of the biology of Amblyomma variegatum and Boophilus decorolatus detached from red-flanked duikers were studied. Smears were also made from the blood of the duikers and examined for the presence of parasites. Anaplasma marginale was the only blood parasite found in the blood smears. Compared with ticks detached from cattle, duiker ticks produced a greater number of eggs. The lengths and breadths of eggs produced by duiker ticks were greater than those of cattle ticks and unlike A. variegatum detached from cattle, the lengths and breadths of eggs of earlier and later ovipositions of this species detached from duiker were similar. Whereas deformed eggs characterised by circular shape and small size constituted a small percentage of eggs of cattle ticks, none was found among eggs of duiker ticks. The pre oviposition, oviposition and eclosion periods, microscopic egg structure, embryonic development, hatching patterns and mortality rates of the eggs of ticks from both hosts were similar.

Anaplasma↗