African swine fever virus (ASFV) usually causes a fatal haemorrhagic disease in domestic pigs. However ASFV has no apparent adverse effects on its vertebrate reservoir hosts, warthogs (Phacochoerus aethiopicus) and bushpigs (Potamochoerus porcus). The virus is maintained in the wild by a campestral cycle between wild members of the family Suidae, especially warthogs, and the argasid ticks which inhabit their burrows. Infection of Ornithodoros moubata with the VIC T90/1 or LIV 13/33 isolate of ASFV did not have an adverse effect on the oviposition rates of infected female ticks. Hatching rates of eggs laid by infected females were also unaffected. In addition infection with ASFV did not cause a significant reduction in the feeding and moulting rates of first nymphal stage ticks from infected females. The feeding rates of adult ticks infected with either of the two isolates of virus were also unaffected. However, infected adult ticks showed an increase in mortality rates over uninfected ticks. After the second blood meal 40.0% of ticks infected with the VIC T901l isolate of ASFV died and 33.3% of ticks infected with LIV 13/33 died, whereas only 4.0% ofuninfected ticks died. Similarly after the third blood meal 93.3% of ticks infected with the VIC T901l isolate of ASFV died and 84.2% of ticks infected with LIV 13/33 died whereas 9.1% ofuninfected ticks died. ASFV is capable of being passed transovarially and transstadially within the Pirbright colony of O. moubata. Filial infection rates were highly variable between individual ticks. After the second blood meal filial infection rates ranged from 1.8% to 31.8% for ticks infected with the VIC T90/1 isolate of ASFV and from 1.2% to 35.5%. After the third blood meal filial infection rates ranged from 15.0% to 32.4% and 1.7% to 44.0% respectively. An increase in the number of blood meals increased the number of females capable of laying infected eggs and increased the filial infection rates of these females. Transstadially infected individual second nymphal stage ticks were capable of excreting up to 104 . sHADsoitick, which is sufficient to infect a pig or warthog. Dissemination and localisation of ASFV within the tick vector was monitored by using anindirect immunoperoxidase staining technique. In ticks which had been infected either orally or by direct inoculation of virus into the haemocoel, viral antigen was detected first in the sexual organs of both male and female ticks. When comparing orally infected ticks and ticks infected by direct inoculation of virus into the haemocoel, the rate at which the various organs become infected did not differ substantially. Furthermore, since infection of ticks either by inoculation of virus directly into the haemocoel (bypassing the gut) or by oral ingestion of virus, resulted in similar infection rates in the organs in the organs (31.7% and 31.0% respectively). It seems unlikely that 0. moubata possesses a gut barrier to ASFV

Four studies consisting of 6 experiments were conducted to investigate the likely mechanisms of actions of feed additives used in the place of antibiotics to improve performance and enteric health in broilers. In the first study, the relationship between digesta pH, body weight and nutrient utilisation in broilers of the same breed but with different propensity for weight gain at different ages were investigated. It was noted that birds in group H (heavy) consumed more feed (P < 0.001) than those in group L (light) during the starter (day 10 to 14) and grower (day 15 to 28) phases. Birds in group H had lower (P < 0.05) caecal pH in the starter and grower phases and lower (P < 0.05) proventriculus pH in grower and finisher (day 29 to 42) phases. In the grower phase, caecal pH was correlated (r = 0.553) with total tract retention of DM and energy utilisation at both the ileal and total tract levels, whereas during the finisher phase, crop pH was correlated with ileal nutrient utilisation, and jejunum pH was correlated with total tract energy utilisation. The data showed that differences in body weight are also reflected in differences in gut pH which is likely indicative of differences in intestinal condition between birds with heavier or lighter body weight. The differences in the gut pH explained about half of the variations in total tract nutrient and energy utilisation. Lower gut pH is advantageous for beneficial bacteria colonization but disadvantageous for pathogenic ones colonization and hence it is likely that birds with the same genetic potential may have differences in growth performance based on the type of bacteria colonizing their gut. In the second study, the response of broiler chickens to the supplementation of benzoic acid (BA) was investigated using growth performance, nutrient and energy utilization, intestinal acidity and histomorphology of the intestine as response criteria, using 945 Ross 308 male broilers in 3 treatments with 7 replicates each for 42 days. In the grower (day 11 to 21) phase, BA supplementation at 0.53 g/kg (BA1) increased (P < 0.001) body weight gain and reduced (P < 0.01) FCR, whereas supplementation at 3.20 g/kg (BA2) reduced (P < 0.005) the feed intake without affecting the body weight gain, resulting in a better FCR. Compared with the control, BA supplementations increased (P < 0.001) the protein and energy efficiency ratios in starter and grower phases and tended (P < 0.10) to increase the energy efficiency ratio in finisher phase (day 22 to 42) or the overall experimental period (day 0 – 42). BA supplementations at both rates reduced the caecal pH. Supplementation of 3.20 g/kg BA stimulated the proliferation of the absorptive cells in the jejunum, as shown in the improvement of the villus and crypt dimensions. The data from this study indicated that dietary supplementation of BA beneficially modified intestinal milieu and improved the growth performance of broiler chicks at 42 d of age. In third study, two experiments were conducted to investigate the benefit of using BA and turmeric meal (TM) individually or in combination using growth performance, nutrient utilization, and intestinal health as response criteria. A total of 300 male one-day old broilers (Ross 308) were assigned in 5 treatments in randomized complete block design with 2x2 + 1 factorial arrangement, with 6 replicate pens and 10 birds each pen. Combination of 1 g/kg BA and 5 g/kg TM improved (P < 0.05) body weight gain relative to the control. Supplementation of 2 g/kg BA reduced the pH in the crop (P < 0.001) and jejunum (P < 0.01), whereas combination of BA and TM at 2 and 10 g/kg respectively reduced digesta pH in the crop (P < 0.001), jejunum (P < 0.01), and caeca (P < 0.05). All of the dietary treatments increased (P < 0.005) villus height, crypt depth and width relative to the control. All dietary treatments increased (P < 0.001) AME and AMEn relative to the control diet, whilst supplementation of 10 g/kg TM only increased energy digestibility (P < 0.05) and ileal digestible energy (P < 0.01). Orthogonal contrasts showed that BA and TM were additive in their effects on the growth performance, digesta pH in the proventriculus, jejunum, and ileum, and energy utilization, but associative on the energy digestibility, as well as the crop and caecal pH. None of the treatment altered the relative weight and length of the digestive tract of 21 days old broiler. These studies pointed out that BA and TM can be used in the diet individually or in combination to improve the enteric health, nutrient and energy utilization, and growth performance of broiler chickens. In the fourth study, two experiments were designed to investigate the efficacy of TM and garlic meal (GM) using growth performance, intestinal pH, and energy and nutrient utilisation as response criteria. Three hundreds male one-day old broilers (Ross 308) were assigned in 5 treatments in randomized complete block design with 2x2 + 1 factorial arrangement, with 6 replicate pens and 10 birds each pen. Results showed that combination of GM and TM at 10 g/kg each increased (P < 0.05) the body weight gain, final body weight, and gain to feed ratio relative to the control and the diet with GM supplementation alone. The crop and caecal pH were reduced (P < 0.05) when the diets were supplemented with TM alone at 10 g/kg. The proventriculus pH also dropped (P < 0.05) following GM and TM mixture supplementation at 10 g/kg each relative to the control. Supplementation of 10 g/kg TM alone or in combination with GM at 5 g/kg each increased (P < 0.05) the apparent ileal energy digestibility and ileal digestible energy. All of the dietary treatments increased (P < 0.001) both AME and AMEn compared with the control. Orthogonal contrasts showed that GM and TM were additive for feed intake, nutrient and energy utilization at both the ileal and total tract levels, but associative in their effects on body weight gain and gain to feed ratio. These studies indicated that GM and TM can be used alone or in combination to support intestinal health, improve energy and nutrient utilization, and stimulate growth performance of broiler chickens. Combination of GM and TM at the rate of 5 g/kg each was optimum for enhancing nutrient and energy utilization and promoting growth performance of broiler chickens. Taken together, these studies showed that benzoic acid and herbal products (garlic and turmeric meal) can be supplemented in the diet alone or in combination to improve the enteric health, nutrient and energy utilization, and growth performance of broiler chickens. Improvements on the growth performance might be attributed to the reduction of the entero-pathogens in the gut, enhancement of intestinal health, alteration of the absorptive cells in the intestinal wall, and improvement in the nutrient and energy utilization.

No description available.

This thesis is an investigation of various sources of animal health data used in disease surveillance for the swine industry in Ontario, Canada. Health data derived from veterinary diagnostic laboratory submission rates, veterinary diagnostic test results, an abattoir, and swine sentinel herds are examined. Based on data from 1998 to 2009, the rate of submissions to a veterinary diagnostic laboratory are dependent on economic variables associated with the swine industry and include: the price paid to swine producers for pigs, the cost of feed (corn), the United States/Canadian dollar exchange rate, and lean-hog futures. An outbreak of porcine circovirus-associated disease (PCVAD) that occurred in the Ontario swine industry from 2004-2006 increased the rate of diagnostic submissions despite the poor economic state of the swine industry at the time. The positivity of porcine reproductive and respiratory syndrome virus (PRRSV) polymerase chain reaction (PCR) tests ordered by veterinary practitioners decreased during the PCVAD outbreak. There was a strong seasonal and yearly affect in the model influencing the positivity of PRRSV PCR tests. However, there was no association between the positivity of PRRSV enzyme-linked immunosorbent assays (ELISA) and the PCVAD outbreak. These findings suggest that the results of tests ordered by veterinarians at diagnostic laboratories have the potential to be used as a form of syndromic surveillance. Swine tonsils (n=395) were collected from a federally-inspected abattoir to determine the prevalence of porcine pathogens, and the most predominant bacterial pathogens isolated were Streptococcus suis (53.7%), Arcanobacterium pyogenes (29.9%), Pasteurella multocida (27.3%), and Streptococcus porcinus (19.5%). Tonsils collected from the held-rail were more likely to be positive for, Staphylococcus hyicus, Streptococcus porcinus, and Streptococcus suis. PRRSV and porcine circovirus-2 were detected in 22.0% and 11.9% of the samples, respectively. Stored serum samples (n=500) from 50 Ontario swine sentinel herds and samples from 2 case herds with clinical disease suggestive of pestivirus infection were tested for Bovine Viral Diarrhea Virus (BVDV) to determine the prevalence of BVDV on Ontario swine farms. The prevalence of BVDV on Ontario swine farms was negligible and the presence of cattle on the same farm was not an identified risk factor.

Thesis (M.Tech.: Homoeopathy) -Dept. of Homoeopathy, Durban Institute of Technology, 2003 xi, 59 leaves / The purpose of this placebo-controlled study was to evaluate the effect of a Homoeopathic complex (Aconitum napelus 30CH, Arnica montana 30CH and China officinalis 30CH) on broiler chickens being transported to the abattoir.

Endotoxin (LPS, lipopolysaccharide) forms an integral part of the outer cellular membrane of gram negative bacteria (GNB). The canines' intestine always contains large amounts of GNB, and hence LPS. If these GNB with their LPS, remain within the intestinal lumen, they are not harmful to the host. When GNB do gain entry into a hosts' circulation a bacteraemia will occur with a concurrent endotoxaemia. In the past, it had been accepted that GNB were, themselves, primarily responsible for the mortality and morbidity of bacteraemic and septicaemic patients. Evidence has emerged to indicate that this is not altogether true as isolated LPS, without the presence of GNB, can also lead to fatalities. Circulating LPS is exceptionally chemically stable and highly toxic to host cells. Antimicrobial chemotherapy can destroy GNB, but this therapy does not reduce the toxicity of LPS, nor does it clear LPS from the circulation. Destruction of the GNB by certain antibiotics can, in fact, increase the concentration of circulating plasma LPS in a host. The functional integrity of the intestinal wall is highly dependent upon an adequate blood supply, and the mucosal cells acts as the primary defence against the potentially pathogenic, endogenous and exogenous GNB and LPS. Once these pathogens become intravascular then the liver is the next most important organ of defence. Shock, irrespective of its aetiology, without adequate therapy, leads to reduced micro-vascular circulation, and thus a state of either localised or generalised hypoxia occurs. Partial or complete intestinal vascular ischaemia will produce a state of regional hypoxia, and lead to damage of the intestinal wall allowing GNB, with their LPS, or LPS by itself, to enter into the hosts' blood circulation. Therefore, an aetiology that gives rise to any type of "classified shock," may eventually give rise to concurrent endotoxaemia. In clinical practice there are numerous different diseases, physical onslaughts, and either acquired or congenital anatomical defects, that can give rise to intestinal vascular ischaemia, and hence, endotoxaemia. Many treatment regimens to combat the effects of an endotoxaemia have been advocated over the years, but this problem still has an unacceptably high mortality and morbidity index, probably because almost all such therapeutic regimens fail to destroy the LPS molecule. Recent clinical studies have shown that immunotherapy is effective in combating gram negative bacteraemia and septicaemia in humans and animals. Research workers have been able to produce a "broad- spectrum" or "polyvalent" equine, hyperimmune, anti-endotoxir, antibody-enriched plasma (ANTI- LPS), with favourab"^ responses recorded when this plasma was used to treat a variety of experimentally-induced endotoxin-shocked subjects. ANTI-LPS significantly reduced the mortality in experimentally produced superior mesenteric arterial occlusion endotoxaemia in rabbits, presumably by neutralizing and opsonizing the circulating plasma LPS. Equine practitioners have reported successful results when ANTI-LPS was incorporated into the treatment of certain medical and surgical equine endotoxic related problems. A ^/ery recent, independent, Canadian study showed the effectivness of ANTI-LPS, where this preparation was tested against other anti-LPS products, to treat experimentally-induced sepsis in rats. The polyvalent equine ANTI- LPS was the most effective, in that its use resulted in the longest survival. In order to establish the generality of the use of equine ANTI-LPS plasma, I have extended these studies to the canine, since an abdominal vascular ischaemia carries a serious, high-risk, surgical emergency with unsatisfactorily high mortality rates, despite successful surgical intervention with concurrent supportive medical therapy. Twenty healthy dogs were divided into four groups; a control group (n=5) and three experimentally treated groups (n=5 in each group). All twenty dogs were subjected to the well-documented cranial (superior) mesenteric arterial occlusion (CMAO) shock model. The three experimental groups received the polyvalent equine, ANTI-LPS at different times and by two different routes, with no side effects being observed in any of these dogs. One group (n=5)received ANTI-LPS s.c. before CMAO was performed, a second group (n= 5) received their dosage of ANTI-LPS i.v. during the three-hour occlusion period, and a third group (n=5) received their dose s.c, within three minutes after the CMAO was released. Survival was recorded when any dog lived for a minimum of 14 days after the occluded vessel was released. All 5/5 (100%) controls died within 17 hours after the release of the occluded vessel, whereas only one of the 15 (6,5%) experimentally ANTI-LPS treated dogs died (P / Thesis (M. Med.Sc.)-University of Natal, Durban, 1986.

No description available.

No description available.

No description available.

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