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Biomedical subjects

D Zwart

Publications and source records attributed to D Zwart.

At least 19 recordsLinked to original sources
PubMed1996

Changes in liver and fat depots of west African dwarf goats (Capra aegagus hircus) after an infection with T. vivax.

Nine West African dwarf goats (Capra aegagus hircus) were each infected experimentally with 3 x 10(7) Trypanosoma vivax parasites. The changes in the plasma concentration of nonesterified fatty acids (NEFA) were monitored during the infection and the level of hepatic triacylglycerols and glycogen was measured postmortem. During the infection they had higher plasma NEFA concentrations than nine uninfected control goats and at postmortem their total liver triacylglycerol and glycogen contents were found to be increased. These observations suggest that the mobilization of the goats' defense mechanisms against the T. vivax infection induced a more intensive fat mobilization resulting in changes in fat metabolism of the liver.

Adipose Tissue↗
PubMed1996

The effect of level of energy intake on rectal temperature and maintenance requirements of West African dwarf goats.

In two separate experiments, the digestible organic matter intake (DOMI) of adult male West African Dwarf goats was measured. Thirteen animals had unrestricted access to feed and 13 others a restricted diet of pelleted lucerne, ranging from 50% up to 140% of maintenance requirements. Four animals received ad libitum grass hay and four others had ad libitum grass straw. Every morning rectal temperature (RT) was measured before feeding. Plotted against DOMI, rectal temperature yielded the following equation as estimated for all animals (s.e.m. in brackets): RT=37.56 (+/- 0.11)+ 0.025( +/- 0.003)*DOMI, n=34, r.s.d.=0.21, R2=0.67. RT was not significantly (P>0.2) influenced by experiment, diet type or system of feeding, but was by the energy intake. The lower RT in animals with low DOMI may be related to a decrease in maintenance requirements of these animals.

Animals↗
PubMed1996

Heat production, body temperature, and body posture in west African dwarf goats infected with Trypanosoma vivax.

The relationships between heat production, body temperature, and body posture (standing/lying) were studied in goats suffering from trypanosomiasis. Sixteen goats were selected and infected with 1 x 10(6) Trypanosoma vivax parasites and 8 goats served as controls. In week 2, 4, and 6 after infection heat production, body posture, and body temperature were measured at 15-minute intervals. Heat production was higher (P < 0.01) in infected animals compared with control animals (342, respectively 306 kJ.kg- 0.75.d-1), body temperature was also higher (P < 0.001) in infected goats (39.78 degrees C, respectively 38.51 degrees C). The standing related energy costs per day were lower in infected animals (27 respectively 36 kJ.kg-0.75.d-1). Infected animals, therefore, masked part of the energy costs of infection by reducing the standing time. The heat production of infected animals was increased by 21 kJ.kg-0.75.d-1 per 1 degree C fever (7% increase). During periods of standing, body temperature increased with time, whereas during lying periods, it decreased. The number of standing periods was increased in infected animals. It was discussed whether postural behaviour is influenced by thermoregulatory mechanisms.

Africa South of the Sahara↗
PubMed1993

The relationship between decrease in feed intake and infection with Trypanosoma congolense and T. vivax in west African dwarf goats.

Twenty-three mature dwarf goats were used to study whether there is a relationship between the decrease in feed intake for individual goats and infection with T.congolense and T. vivax. Furthermore, it was investigated how rectal temperatures and blood parameters were affected by the T. congolense infection and how changes in these parameters can be used to predict the effect of a T. vivax infection on feed intake. For individual goats a ranking correlation was found between relative dry matter intake and infection (r = 0.59; p < .05). Animals with the most marked decrease in dry matter intake during the T. congolense infection showed a smaller increase in urea and a higher increase in non esterified fatty acids and beta-hydroxy butyrate levels in their blood. Evidence was obtained that the relative decrease in dry matter intake for individual goats during a T. vivax infection can be predicted on the basis of urea and creatinine responses measured in the blood during a previous infection with T. congolense infection.

Animals↗
PubMed1992

Towards a sustainable livestock production in developing countries and the importance of animal health strategy therein.

Livestock and animal health development projects have not always led to substantial increases in animal productivity or in farmers' welfare. Some have even resulted in unsustainable systems, when they were not based on an understanding of (livestock) production systems. The multipurpose functions of livestock and complex relationships between the biological, technical and social components require a systems approach, whereby nutrition, animal health, breeding, biotechnology knowhow, inputs and technologies are used to optimise resource use. The challenge for developed and developing countries is to reverse the current degradation of the environment, and arrive at sustainable increases in crop and livestock production to secure present and future food supplies. For rural development, governments should show long term commitment and political will to support the rural population in development programmes, because smallholders (including women and landless livestock keepers) represent a large labour force in developing countries. Different systems need different approaches. Pastoral systems must focus on effective management of grazing pressure of the rangelands. Communal rangelands management involves not only the development and application of technologies (e.g. feedlots, vaccination campaigns), but also land tenure policies, institutional development, economic return and a reduction in the number of people depending upon livestock. Smallholder mixed farms must aim at intensification of the total production system, in which external inputs are indispensable, but with the emphasis on optimum input-output relationships by reducing resource losses due to poor management. Resource-poor farming systems must aim at the improved management of the various livestock species in backyards and very small farms, and proper packages for cattle, buffaloes, sheep, goats, rabbits and poultry should be developed. Specialised commercial livestock farming systems (poultry, pigs, dairy or meat) can only be sustainable with adequate marketing, supply of quality feed, veterinary services, labour, management and control of pollution. Animal health programmes play a keyrole in the proposed system approach.

Agriculture↗
PubMed1992

The effect of T. vivax infection in west African dwarf goats on energy and nitrogen metabolism.

To investigate how T. vivax affects metabolism in dwarf goats, nine wethers (infection group) given alfalfa pellets ad libitum were infected intravenously and food intake was recorded up to 49 days after infection in the infection group and in the control group (n = 9). Controls received the same diet, ad libitum before infection and in restricted amounts after infection in order to obtain similar intakes in the two groups. Digestible organic matter intake (DOMI) and nitrogen balance (NB) were determined during four balance trials. All animals were bled regularly to measure parasitaemia, packed cell volume (PCV) and a number of serum metabolites. All infected animals showed symptoms typical for T. vivax infection as judged by parasitaemia, PCV and rectal temperature. Infection had a non-uniform negative effect on food intake. Compared with controls at equal DOMI, NB was lower in infected animals, the difference being significant 4 weeks after infection. This was caused by a gradual increase in NB at equal DOMI of the control group. The NB of the ad libitum fed infected animals 2 and 4 weeks after infection was comparable to values normally found in healthy ad libitum fed dwarf goats with an equal DOMI. NEFA values in serum were significantly elevated after infection. Except for two infected animals with an extremely low food intake towards the end of the experiment, no rise in serum ketone bodies was evident. After infection, serum protein increased, differences with controls being significant 4 and 7 weeks after infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗
PubMed1991

Effect of Trypanosoma vivax infection on energy and nitrogen metabolism of west African dwarf goats.

A study was conducted using 32 mature 22-kg West African Dwarf Goats to measure the effect of Trypanosoma vivax infection on energy and nitrogen metabolism. Sixteen goats were infected intravenously with 14 X 10(6) T. vivax. Sixteen control goats were sham-injected. Digestibility and metabolizability of energy and N balance were measured for each goat. Heat production and energy balances were measured per treatment group from 1 wk before infection to 6 wk after infection. Goats were fed alfalfa pellets (10% above maintenance). Treated goats had a reduced (P less than .05) packed cell volume (38 to 40% before infection vs 20 to 25% 6 wk after infection) and an increased (P less than .05) rectal temperature. Log parasitemia/ml was about 6.0 to 6.2. Parasitized goats showed increased urine creatinine excretion at wk 2 postinfection. After infection, feed intake was reduced (about 15%; P less than .05) and greater variability in intake was noted. Treated and control goats had similar N output and energy output in urine. Metabolizability of energy intake was similar at 42.7 vs 42.1% in treated vs control goats, respectively. Heat production in infected goats was increased by about 15%. Treated goats lost more weight and had a lower N balance than control goats (P less than .05). The calculated maintenance energy requirement for infected goats (464 kJ ME/kg.75) was 25% greater than for control goats (375 kJ ME/kg.75).

Animals↗
PubMed1991

Effect of Trypanosoma vivax infection on body temperature, feed intake, and metabolic rate of West African dwarf goats.

Thirty-two mature dwarf goats weighing between 16 and 30 kg (22.7 +/- 3.7, SD) were used to study the effect of Trypanosoma vivax infection on rectal temperature (RT), feed intake (DMI), and metabolic rate. Sixteen of the goats were infected intravenously with 14 X 10(6) T. vivax each; the 16 others served as controls. Animals were fed at about 1.1 times maintenance. Heat production was measured from 1 wk preinfection to 6 wk postinfection. From data on successive 9-min periods, heat production was calculated per 24-h period and separately for 0700 to 2000 (day period) and for 2000 to 0700 (night period). Rectal temperature was measured twice weekly. Compared with controls, animals infected with T. vivax developed and maintained a 1 degree C higher RT and a higher metabolic rate. After the prepatent period of 5 to 7 d, during which RT remained normal, all infected goats had a period of about 7 d with constant high temperatures. After that initial episode, RT fluctuated. Heat production of infected animals was increased by 15.6 kcal.d-1.kg-.75, or about 16%. This increase in heat production was greater during the night (22 kcal.d-1.kg-.75) than during the day (14 kcal.d-1.kg-.75). After T. vivax infection, large differences in DMI among animals were apparent. In four animals, a clear relation between DMI and RT was noted, but in 12 animals no such relationship was apparent.

Animals↗
PubMed1990

Influence of fever and flurbiprofen on trypanosome growth.

The administration of flurbiprofen, a potent non-steroidal anti-inflammatory drug (NSAID), to goats infected with trypanosomes resulted in high elevated parasitaemia and suppression of fever. In contrast to goats, rats infected with trypanosomes do not show febrile reactions. Therefore, the role of body temperature was investigated with yeast-induced fever in Trypanosoma evansi and T. brucei infected rats. These investigations did not support the hypothesis that a high body temperature causes a drop in parasitaemia. In goats infected with trypanosomes, it is also unlikely that fever has an inhibitory influence on the parasitaemia. In these animals, rises in parasitaemia could be provoked by doses of flurbiprofen as low as 1/20 of the normal doses and these doses did not or only partly suppressed fever. No effect on parasite growth could be obtained when flurbiprofen was added in concentrations up to 32 micrograms/ml directly to T. brucei cultures. Moreover, no growth promoting factor(s) could be identified in vitro in serum from flurbiprofen-treated goats.

Animals↗
PubMed1985

[Autochthonous babesiosis in dogs in the Netherlands?].

For the first time cases of babesiosis have been diagnosed in dogs that had not been abroad. Three cases were seen in the province of Gelderland (Bennekom, Elspeet), two in North-Holland (Koog aan de Zaan). A female Dermacentor reticulatus tick, the main vector of the disease in Europe, was found on one of the dogs at Koog; previously specimens of this tick species had only occasionally been seen on dogs returning from abroad. Serological evidence was obtained that in at least four of the cases European Babesia canis, transmitted by Dermacentor ticks, was involved.

Animals↗
PubMed1985

Flurbiprofen and immunosuppression of Trypanosoma brucei infection in the goat.

Goats infected with Trypanosoma brucei and treated with the non-steroidal anti-inflammatory agent flurbiprofen, showed a marked increase in parasitaemia, followed in one of the four goats by death. The in vitro response to mitogens of peripheral blood lymphocytes and separated T- and B-lymphocytes from healthy goats treated with flurbiprofen was normal when compared with non-treated animals. T. brucei-infected goats, not treated with flurbiprofen, showed a marked immunosuppression which was mainly localized in the B-enriched lymphocyte fraction. A combination of T. brucei infection and treatment with flurbiprofen led to even more suppression, because the T-lymphocyte function was also suppressed. It is concluded that flurbiprofen first causes a rise in the parasitaemia and that this high parasitaemia is responsible for the observed immunosuppression.

Animals↗
PubMed1984

Studies on the influence of non-steroidal anti-inflammatory drugs upon trypanosomiasis in goats and sheep.

The non-steroidal anti-inflammatory drug (NSAID) flurbiprofen caused a rise in parasitaemia in goats infected with Trypanosoma vivax, Trypanosoma congolense and Trypanosoma brucei. All trypanosome-infected goats treated with flurbiprofen showed many dividing trypanosomes. This also included the short-stumpy forms of T. brucei. In T. vivax-infected goats flurbiprofen treatment resulted in 100% mortality in the acute and chronic stages of the infection. The increase in parasitaemia of T. brucei infected goats, treated with flurbiprofen, was not associated with an increase in mortality. The increase in parasitaemia of T. congolense-infected goats, treated with flurbiprofen, tended to be associated with a somewhat higher mortality but this was statistically not significant. The significant rise in parasitaemia could be reproduced in T. brucei-infected sheep without, however, killing the animals. Two other NSAIDs were also studied. Suprofen caused a rise in parasitaemia and 100% mortality when given to goats in the acute stage of T. vivax infection. Results with flunixin meglumine, when tested in T. brucei infected goats, were not conclusive.

Acute Disease↗
PubMed1981

Imidocarb: a chemoprophylactic experiment with Babesia canis.

Eight dogs, given imidocarb dipropionate subcutaneously at a dose of 6 mg/kg, were challenged with a sporozoite stabilate of a French strain of Babesia canis, prepared from infected Dermacentor reticulatus ticks, 2, 3, 4 or 5 weeks after treatment. Three control dogs were similarly infected but not preventively treated. One of the controls and one of the dogs treated 5 weeks prior to challenge died of babesiosis. Prepatent and incubation periods were similar in treated and control dogs, and all dogs showed important reductions in the packed cell volume. Relapses were commonly seen after recovery from the initial reaction. Although further work is needed before a final conclusion can be drawn to whether imidocarb is suitable as a chemoprophylactic against B. canis infection, it can be used as a curative drug.

Amidines↗
PubMed1980

Blood parasites of sheep in the Netherlands. II. Babesia motasi (Sporozoa, Babesiidae).

A large Babesia species occurs in sheep on the North Sea islands of the Netherlands. The tick Haemaphysalis punctata is a vector. Its pathogenicity appears to be low. It is morphologically similar to a Turkish strain, considered to be B. motasi, which is also transmitted by Haemaphysalis ticks. It differs from the Turkish parasite serologically as well as in cross-immunity tests and in not being effective to goats. There may be a group of morphologically similar parasites with serological differences and different infectivity for sheep and goats. As it is impossible to know which one is to be considered as the original B. motasi, we designate the Dutch parasite as B. motase (Netherlands). Anaplasma mesaeterum was found to occur on the island of Texel as well as on Ameland, where it had been found initially.

Animals↗
PubMed1980

Pitfalls of salicylhydroxamic acid plus glycerol treatment of T. vivax infected goats.

A dosage regime of SHAM (260 to 355 mg/kg) plus glycerol (890 to 1216 mg/kg), cleared T. vivax from peripheral blood of infected goats. Relapses occurred on two occasions in one goat and death during infusion of the drug in two other goats. Pharmacokinetic studies showed that both SHAM and glycerol are rapidly eliminated, the elimination possibly being slower in infected than in uninfected goats. For this reason and also because of the poor solubility of SHAM, very large volumes (500-1000 ml) had to be infused intravenously to obtain therapeutic plasma concentrations. The difficulties of adjusting the pH, the large volumes to be injected combined with the narrow margin between therapeutic and lethal dose preclude practical application of this form of treatment. Toxicity became apparent as a marked increase in heart rate and cessation of the ruminal movements which lasted for about 6 hours. A Herxheimer reaction may play an additional role in infected goats. Relapses may be due either to the fact that the levels of the drugs in the tissue were too low, or to the presence of a sub-population of T. vivax which is not susceptible to the treatment with SHAM plus glycerol.

Animal Diseases↗