Sinais clínicos e ocorrência de anticorpos anti-Chlamydophila abortus em ovinos de São Paulo e Minas Gerais

A Chlamydophila abortusi, anteriormente conhecida como Chlamydia psittaci sovovar 1, é uma bactéria Gram negativa, intracelular obrigatória. Esse micro-organismo é frequentemente encontrado em distúrbios reprodutivos em ovinos, bovinos e caprinos, sendo o aborto epizoótico dos bovinos e o aborto enzoótico dos ovinos e caprinos as manifestações mais importantes. Considerando-se o pouco material literário a respeito da clamidofilose no Brasil, a pesquisa teve como objetivo determinar a presença de anticorpos fixadores de complemento anti-Chlamydophila abortusi, correlacionando os resultados obtidos com achados no exame clínico e histórico dos animais, além de alterações nos índices zootécnicos, em especial na esfera reprodutiva, tais como alto índice de repetição de cio, número elevado de abortamentos, elevado número de natimortos, entre outros. Foram testadas para prova de fixação do complemento 220 amostras de soro de ovinos, de 26 propriedades, distribuídas em 19 municípios, com relato de manifestação reprodutiva, obtendo-se 19,55% (43/220) de testes positivos para Chlamydophila abortusi, com ocorrência de foco constatada de 61,53%. No geral, a titulação de anticorpos encontrada foi baixa, com título não superior a 64. A frequência de manifestação reprodutiva mais observada foi o aborto, representando 65,12% (28/43) do número total de animais soropositivos, seguido de repetição de cio juntamente com nascimento de cordeiro fraco, com frequência de 6,98% (3/43) e, por fim, morte neonatal com 4,65% (2/43), sendo que não houve associação significativa entre animais que foram positivos ao teste e a esses fatores.

Sinais clínicos e ocorrência de anticorpos anti-Chlamydophila abortus em ovinos de São Paulo e Minas Gerais

A Chlamydophila abortus, anteriormente conhecida como Chlamydia psittaci sovovar 1, é uma bactéria Gram negativa, intracelular obrigatória. Esse micro-organismo é frequentemente encontrado em distúrbios reprodutivos em ovinos, bovinos e caprinos, sendo o aborto epizoótico dos bovinos e o aborto enzoótico dos ovinos e caprinos as manifestações mais importantes. Considerando-se o pouco material literário a respeito da clamidofilose no Brasil, a pesquisa teve como objetivo determinar a presença de anticorpos fixadores de complemento anti-Chlamydophila abortus, correlacionando os resultados obtidos com achados no exame clínico e histórico dos animais, além de alterações nos índices zootécnicos, em especial na esfera reprodutiva, tais como alto índice de repetição de cio, número elevado de abortamentos, elevado número de natimortos, entre outros. Foram testadas para prova de fixação do complemento 220 amostras de soro de ovinos, de 26 propriedades, distribuídas em 19 municípios, com relato de manifestação reprodutiva, obtendo-se 19,55% (43/220) de testes positivos para Chlamydophila abortus, com ocorrência de foco constatada de 61,53%. No geral, a titulação de anticorpos encontrada foi baixa, com título não superior a 64. A frequência de manifestação reprodutiva mais observada foi o aborto, representando 65,12% (28/43) do número total de animais soropositivos, seguido de repetição de cio juntamente com nascimento de cordeiro fraco, com frequência de 6,98% (3/ 43) e, por fim, morte neonatal com 4,65% (2/43), sendo que não houve associação significativa entre animais que foram positivos ao teste e a esses fatores.

Importanza prognostica delle citochine e loro ruolo nell'immunomodulazione: risultati di studi sperimentali in vivo e in vitro

Citokines are proteins produced by several cell types and secreted in response to various stimuli. These molecules are able to modify the behaviour of other cells inducing activities like growth, differentiation and apoptosis. In the last years, veterinary scientists have investigated the role played by these factors; in fact, cytokines can act as intercellular communicative signals in immune response, cell damage repair and hematopoiesis. Up to date, various cytokines have been identified and in depth comprehension of their effects in physiology, pathology and therapy is an interesting field of research. This thesis aims to understand the role played by these mediators during natural or experimentally induced pathologies. In particular, it has been evaluated the genic and protein expressions of a large number of cytokines during several diseases and starting from different matrix. Considering the heterogeneity of materials used in experimentations, multiple methods and protocols of nucleic acids and proteins extractions have been standardized. Results on cytokines expression obtained from various in vitro and in vivo experimental studies have shown how important these mediators are in regulation and modulation of the host immune response also in veterinary medicine. In particular, the analysis of inflammatory and septic markers, like cytokines, has allowed a better understanding in the pathogenesis during horse Recurrent Airway Obstruction, foal sepsis, Bovine Viral Diarrhea Virus infection and dog Parvovirus infection and the effects of these agents on the host immune system. As experimentations with mice have shown, some pathologies of the respiratory and nervous system can be reduced or even erased by blocking cytokines inflammatory production. The in vitro cytokines expression evaluation in cells which are in vivo involved in the response to exogenous (like pathogens) or endogenous (as it happens during autoimmune diseases) inflammatory stimuli could represent a model for studying citokines effects during the host immune response. This has been analyzed using lymphocytes cultured with several St. aureus strains isolated from bovine mastitic milk and different colostrum products. In the first experiment different cytokines were expressed depending on enterotoxins produced, justifying a different behaviour of the microrganism in the mammal gland. In the second one, bone marrow cells derived incubated with murine lymphocytes with colostrum products have shown various cluster of differentiation expression , different proliferation and a modified cytokines profile. A better understanding of cytokine expression mechanisms will increase the know-how on immune response activated by several pathogen agents. In particular, blocking the cytokine production, the inhibition or catalyzation of the receptor binding mechanism and the modulation of signal transduction mechanism will represent a novel therapeutic strategy in veterinary medicine.

Meccanismi evolutivi dei parapoxvirus: caratterizzazione genomica di pseudocowpoxvirus e messa a punto di sistemi per lo studio delle ricombinazioni

The Poxviruses are a family of double stranded DNA (dsDNA) viruses that cause disease in many species, both vertebrate and invertebrate. Their genomes range in size from 135 to 365 kbp and show conservation in both organization and content. In particular, the central genomic regions of the chordopoxvirus subfamily (those capable of infecting vertebrates) contain 88 genes which are present in all the virus species characterised to date and which mostly occur in the same order and orientation. In contrast, however, the terminal regions of the genomes frequently contain genes that are species or genera-specific and that are not essential for the growth of the virus in vitro but instead often encode factors with important roles in vivo including modulation of the host immune response to infection and determination of the host range of the virus. The Parapoxviruses (PPV), of which Orf virus is the prototypic species, represent a genus within the chordopoxvirus subfamily of Poxviridae and are characterised by their ability to infect ruminants and humans. The genus currently contains four recognised species of virus, bovine papular stomatitis virus (BPSV) and pseudocowpox virus (PCPV) both of which infect cattle, orf virus (OV) that infects sheep and goats, and parapoxvirus of red deer in New Zealand (PVNZ). The ORFV genome has been fully sequenced, as has that of BPSV, and is ~138 kb in length encoding ~132 genes. The vast majority of these genes allow the virus to replicate in the cytoplasm of the infected host cell and therefore encode proteins involved in replication, transcription and metabolism of nucleic acids. These genes are well conserved between all known genera of poxviruses. There is however another class of genes, located at either end of the linear dsDNA genome, that encode proteins which are non-essential for replication and generally dictate host range and virulence of the virus. The non-essential genes are often the most variable within and between species of virus and therefore are potentially useful for diagnostic purposes. Given their role in subverting the host-immune response to infection they are also targets for novel therapeutics. The function of only a relatively small number of these proteins has been elucidated and there are several genes whose function still remains obscure principally because there is little similarity between them and proteins of known function in current sequence databases. It is thought that by selectively removing some of the virulence genes, or at least neutralising the proteins in some way, current vaccines could be improved. The evolution of poxviruses has been proposed to be an adaptive process involving frequent events of gene gain and loss, such that the virus co-evolves with its specific host. Gene capture or horizontal gene transfer from the host to the virus is considered an important source of new viral genes including those likely to be involved in host range and those enabling the virus to interfere with the host immune response to infection. Given the low rate of nucleotide substitution, recombination can be seen as an essential evolutionary driving force although it is likely underestimated. Recombination in poxviruses is intimately linked to DNA replication with both viral and cellular proteins participate in this recombination-dependent replication. It has been shown, in other poxvirus genera, that recombination between isolates and perhaps even between species does occur, thereby providing another mechanism for the acquisition of new genes and for the rapid evolution of viruses. Such events may result in viruses that have a selective advantage over others, for example in re-infections (a characteristic of the PPV), or in viruses that are able to jump the species barrier and infect new hosts. Sequence data related to viral strains isolated from goats suggest that possible recombination events may have occurred between OV and PCPV (Ueda et al. 2003). The recombination events are frequent during poxvirus replication and comparative genomic analysis of several poxvirus species has revealed that recombinations occur frequently on the right terminal region. Intraspecific recombination can occur between strains of the same PPV species, but also interspecific recombination can happen depending on enough sequence similarity to enable recombination between distinct PPV species. The most important pre-requisite for a successful recombination is the coinfection of the individual host by different virus strains or species. Consequently, the following factors affecting the distribution of different viruses to shared target cells need to be considered: dose of inoculated virus, time interval between inoculation of the first and the second virus, distance between the marker mutations, genetic homology. At present there are no available data on the replication dynamics of PPV in permissive and non permissive hosts and reguarding co-infetions there are no information on the interference mechanisms occurring during the simultaneous replication of viruses of different species. This work has been carried out to set up permissive substrates allowing the replication of different PPV species, in particular keratinocytes monolayers and organotypic skin cultures. Furthermore a method to isolate and expand ovine skin stem cells was has been set up to indeep further aspects of viral cellular tropism during natural infection. The study produced important data to elucidate the replication dynamics of OV and PCPV virus in vitro as well as the mechanisms of interference that can arise during co-infection with different viral species. Moreover, the analysis carried on the genomic right terminal region of PCPV 1303/05 contributed to a better knowledge of the viral genes involved in host interaction and pathogenesis as well as to locate recombination breakpoints and genetic homologies between PPV species. Taken together these data filled several crucial gaps for the study of interspecific recombinations of PPVs which are thought to be important for a better understanding of the viral evolution and to improve the biosafety of antiviral therapy and PPV-based vectors.

Agenti di encefalopatie spongiformi trasmissibili e zoonosi: tipizzazione molecolare

Transmissible spongiform encephalopathies (TSE) are neurodegenerative diseases caused by the conversion of the host-encoded cellular protein (PrPC) to a disease-associated isoform (PrPSc). The agent responsible for prion diseases may exist as different strains with specific biological and biochemical properties. According to the protein-only hypothesis, prion strain diversity is enciphered in PrPSc conformation. Molecular strain typing methods are based on the electrophoretic mobility of protease resistant core of PrPSc, on the susceptibility to protease digestion, on the glycosylation profile of PrPres and on the conformational stability of PrPSc. In this study a new conformational stability assay was developed based on the differential solubility of PrPC and PrPSc: CSSA (conformational stability and solubility assay). The conformational stability assay was performed by measuring PrPSc solubility in homogenates treated with increasing concentrations of GdnHCl, in the absence of proteinase K. Indeed, dose-response curves allowed estimation of the concentration of GdnHCl able to solubilise 50% of PrPSc. The results showed that this method is valuable for the biochemical typing of strains in bank voles and it is also a promising tool for molecular analysis of natural prion isolates. CSSA also revealed strain-specific PrPSc conformational stabilities of ovine natural isolates so that this feature, combined with the N-terminal PrPSc cleavage, allowed differentiation of classical scrapie, including CH1641-like, from natural goat BSE and experimental sheep BSE. In view of the implications concerning strain similarity between animal and human TSEs, the physico-chemical properties of the Nor98 with two human prion diseases (VPSPr and GSS) were compared in order to investigate the extent of the similarity between animal and human prion strains. The results showed an unexpected heterogeneity of the molecular features among human and sheep TSEs associated with internal PrPres fragments with the possible exception of Nor98 and a case of GSS P102L. These similarities and differences need further investigation by N- and C-terminal sequencing and biological characterization.

On the aetiology of bovine neonatal pancytopenia (BNP)

Bovine Neonatal Pancytopenia (BNP) is a novel haemorrhagic disease in sucking calves, characterised by bleeding, haematological changes and high mortality. Dams that gave birth to BNP affected calves were immunized with PregSure® BVD, a highly adjuvanted vaccine against Bovine Viral Diarrhoea (BVD). We can show that bioprocess impurities in the vaccine, originating from the cell line used for vaccine production induces alloantibodies in vaccinated cattle. Via flow cytometry and immunoprecipitation we can demonstrate that PregSure® BVD immunization leads to BNP alloantibody production. BNP alloantibodies target highly polymorphic bovine MHC-I molecules (BoLA I). We sequenced eight BoLA I variants expressed by the production cell line and identified three alleles which are responsible for the majority of PregSure® BVD induced BoLA I reactivity. The BoLA I alleles of BNP unaffected calves are not recognized by the BNP associated alloantibodies of their respective dams. We also examined whether BNP alloantibodies cross-react with human cells, thus being a potential hazard for human colostrum consumers and could show that BNP alloantibodies are cross-reactive to human MHC-I and can even be found in commercial colostrum powder manufactured from cows immunized with PregSure® BVD. Overall we can demonstrate that BNP is a vaccine induced alloimmune disease.

Role of selective V2-receptor-antagonism in septic shock: a randomized, controlled, experimental study

ABSTRACT : INTRODUCTION : V2-receptor (V2R) stimulation potentially aggravates sepsis-induced vasodilation, fluid accumulation and microvascular thrombosis. Therefore, the present study was performed to determine the effects of a first-line therapy with the selective V2R-antagonist (Propionyl1-D-Tyr(Et)2-Val4-Abu6-Arg8,9)-Vasopressin on cardiopulmonary hemodynamics and organ function vs. the mixed V1aR/V2R-agonist arginine vasopressin (AVP) or placebo in an established ovine model of septic shock. METHODS : After the onset of septic shock, chronically instrumented sheep were randomly assigned to receive first-line treatment with the selective V2R-antagonist (1 g/kg per hour), AVP (0.05 g/kg per hour), or normal saline (placebo, each n = 7). In all groups, open-label norepinephrine was additionally titrated up to 1 g/kg per minute to maintain mean arterial pressure at 70 ± 5 mmHg, if necessary. RESULTS : Compared to AVP- and placebo-treated animals, the selective V2R-antagonist stabilized cardiopulmonary hemodynamics (mean arterial and pulmonary artery pressure, cardiac index) as effectively and increased intravascular volume as suggested by higher cardiac filling pressures. Furthermore, left ventricular stroke work index was higher in the V2R-antagonist group than in the AVP group. Notably, metabolic (pH, base excess, lactate concentrations), liver (transaminases, bilirubin) and renal (creatinine and blood urea nitrogen plasma levels, urinary output, creatinine clearance) dysfunctions were attenuated by the V2R-antagonist when compared with AVP and placebo. The onset of septic shock was associated with an increase in AVP plasma levels as compared to baseline in all groups. Whereas AVP plasma levels remained constant in the placebo group, infusion of AVP increased AVP plasma levels up to 149 ± 21 pg/mL. Notably, treatment with the selective V2R-antagonist led to a significant decrease of AVP plasma levels as compared to shock time (P < 0.001) and to both other groups (P < 0.05 vs. placebo; P < 0.001 vs. AVP). Immunohistochemical analyses of lung tissue revealed higher hemeoxygenase-1 (vs. placebo) and lower 3-nitrotyrosine concentrations (vs. AVP) in the V2R-antagonist group. In addition, the selective V2R-antagonist slightly prolonged survival (14 ± 1 hour) when compared to AVP (11 ± 1 hour, P = 0.007) and placebo (11 ± 1 hour, P = 0.025). CONCLUSIONS : Selective V2R-antagonism may represent an innovative therapeutic approach to attenuate multiple organ dysfunction in early septic shock.

Combining 3D tracking and surgical instrumentation to determine the stiffness of spinal motion segments: a validation study

The spine is a complex structure that provides motion in three directions: flexion and extension, lateral bending and axial rotation. So far, the investigation of the mechanical and kinematic behavior of the basic unit of the spine, a motion segment, is predominantly a domain of in vitro experiments on spinal loading simulators. Most existing approaches to measure spinal stiffness intraoperatively in an in vivo environment use a distractor. However, these concepts usually assume a planar loading and motion. The objective of our study was to develop and validate an apparatus, that allows to perform intraoperative in vivo measurements to determine both the applied force and the resulting motion in three dimensional space. The proposed setup combines force measurement with an instrumented distractor and motion tracking with an optoelectronic system. As the orientation of the applied force and the three dimensional motion is known, not only force-displacement, but also moment-angle relations could be determined. The validation was performed using three cadaveric lumbar ovine spines. The lateral bending stiffness of two motion segments per specimen was determined with the proposed concept and compared with the stiffness acquired on a spinal loading simulator which was considered to be gold standard. The mean values of the stiffness computed with the proposed concept were within a range of ±15% compared to data obtained with the spinal loading simulator under applied loads of less than 5 Nm.

Selective inferior petrosal sinus sampling without venous outflow diversion in the detection of a pituitary adenoma in Cushing's syndrome

Conventional MRI may still be an inaccurate method for the non-invasive detection of a microadenoma in adrenocorticotropin (ACTH)-dependent Cushing's syndrome (CS). Bilateral inferior petrosal sinus sampling (BIPSS) with ovine corticotropin-releasing hormone (oCRH) stimulation is an invasive, but accurate, intervention in the diagnostic armamentarium surrounding CS. Until now, there is a continuous controversial debate regarding lateralization data in detecting a microadenoma. Using BIPSS, we evaluated whether a highly selective placement of microcatheters without diversion of venous outflow might improve detection of pituitary microadenoma.

Biocompatibility assessment of the first generation PediaFlow pediatric ventricular assist device

The PediaFlow pediatric ventricular assist device is a miniature magnetically levitated mixed flow pump under development for circulatory support of newborns and infants (3-15 kg) with a targeted flow range of 0.3-1.5 L/min. The first generation design of the PediaFlow (PF1) was manufactured with a weight of approximately 100 g, priming volume less than 2 mL, length of 51 mm, outer diameter of 28 mm, and with 5-mm blood ports. PF1 was evaluated in an in vitro flow loop for 6 h and implanted in ovines for three chronic experiments of 6, 17, and 10 days. In the in vitro test, normalized index of hemolysis was 0.0087 ± 0.0024 g/100L. Hemodynamic performance and blood biocompatibility of PF1 were characterized in vivo by measurements of plasma free hemoglobin, plasma fibrinogen, total plasma protein, and with novel flow cytometric assays to quantify circulating activated ovine platelets. The mean plasma free hemoglobin values for the three chronic studies were 4.6 ± 2.7, 13.3 ± 7.9, and 8.8 ± 3.3 mg/dL, respectively. Platelet activation was low for portions of several studies but consistently rose along with observed animal and pump complications. The PF1 prototype generated promising results in terms of low hemolysis and platelet activation in the absence of complications. Hemodynamic results validated the magnetic bearing design and provided the platform for design iterations to meet the objective of providing circulatory support for young children with exceptional biocompatibility.

[Anaesthesia and breast-feeding: should breast-feeding be discouraged?]

Until a few years ago an interruption of breast-feeding for 12 or even 24 hours was recommended for breast-feeding mothers after anaesthesia, this is no longer valid. If it is the mother's wish, if she is sufficiently awake and physically able, there is no reason not to start breast-feeding a mature and healthy baby immediately after recovery from a general or regional anaesthesia. Even breast-feeding after a Caesarean delivery with administration of the common anaesthetics in the usual (single) doses is no longer considered to be a problem since the amount of the substance taken up from colostrum is vanishingly small in comparison to the amount that is transferred by transplacental routes. Neither the pharmacological properties of the drugs used in association with anaesthesia nor clinical experience justify an interruption of breast-feeding.

Preparation of intact bovine tail intervertebral discs for organ culture

The intervertebral disc (IVD) is the joint of the spine connecting vertebra to vertebra. It functions to transmit loading of the spine and give flexibility to the spine. It composes of three compartments: the innermost nucleus pulposus (NP) encompassing by the annulus fibrosus (AF), and two cartilaginous endplates connecting the NP and AF to the vertebral body on both sides. Discogenic pain possibly caused by degenerative intervertebral disc disease (DDD) and disc herniations has been identified as a major problem in our modern society. To study possible mechanisms of IVD degeneration, in vitro organ culture systems with live disc cells are highly appealing. The in vitro culture of intact bovine coccygeal IVDs has advanced to a relevant model system, which allows the study of mechano-biological aspects in a well-controlled physiological and mechanical environment. Bovine tail IVDs can be obtained relatively easy in higher numbers and are very similar to the human lumbar IVDs with respect to cell density, cell population and dimensions. However, previous bovine caudal IVD harvesting techniques retaining cartilaginous endplates and bony endplates failed after 1-2 days of culture since the nutrition pathways were obviously blocked by clotted blood. IVDs are the biggest avascular organs, thus, the nutrients to the cells in the NP are solely dependent on diffusion via the capillary buds from the adjacent vertebral body. Presence of bone debris and clotted blood on the endplate surfaces can hinder nutrient diffusion into the center of the disc and compromise cell viability. Our group established a relatively quick protocol to "crack"-out the IVDs from the tail with a low risk for contamination. We are able to permeabilize the freshly-cut bony endplate surfaces by using a surgical jet lavage system, which removes the blood clots and cutting debris and very efficiently reopens the nutrition diffusion pathway to the center of the IVD. The presence of growth plates on both sides of the vertebral bone has to be avoided and to be removed prior to culture. In this video, we outline the crucial steps during preparation and demonstrate the key to a successful organ culture maintaining high cell viability for 14 days under free swelling culture. The culture time could be extended when appropriate mechanical environment can be maintained by using mechanical loading bioreactor. The technique demonstrated here can be extended to other animal species such as porcine, ovine and leporine caudal and lumbar IVD isolation.

Hydrogels for nucleus replacement—Facing the biomechanical challenge

Hydrogels are considered promising for disc regeneration strategies. However, it is currently unknown whether the destruction of the natural interface between nucleus and surrounding structures caused by nucleotomy and an inadequate annulus closure diminishes the mechanical competence of the disc. This in vitro study aimed to clarify these mechanisms and to evaluate whether hydrogels are able to restore the biomechanical behaviour of the disc. Nucleus pressure in an ovine intervertebral disc was measured in vivo during day and night and adapted to an in vitro axial compressive diurnal (15min) and night (30min) load. Effects of different defects on disc height and nucleus pressure were subsequently measured in vitro using 30 ovine motion segments. Following cases were considered: intact; annulus incision repaired by suture and glue; annulus incision with removal and re-implantation of nucleus tissue; and two different hydrogels repaired by suture and glue. The intradiscal pressure in vivo was 0.75MPa during day and 0.5MPa during night corresponding to an in vitro axial compressive force of 130 and 58N, respectively. The compression test showed that neither the implantation of hydrogels nor the re-implantation of the natural nucleus, assumed as being the ideal implant, was able to restore the mechanical functionality of an intact disc. Results indicate the importance of the natural anchorage of the nucleus with its surrounding structures and the relevance of an appropriate annulus closure. Therefore, hydrogels that are able to mimic the mechanical behaviour of the native nucleus may fail in restoring the mechanical behaviour of the disc.

Management effects on colostrogenesis in small ruminants: a review

Colostrum feeding in small ruminants is crucial during the first hours after birth due to the lack of Ig transfer during pregnancy via the placenta. In addition the immature immune system of the neonate is slow to produce its own Ig during the first weeks of life. Colostrogenesis, i.e. the transfer of Ig from blood into mammary secretions, starts several weeks prepartum. In goat plasma, immunoglobulin G (IgG) concentration decreases by around 38% from the third month of gestation until partum, which coincides with the dry period. Thus, management during the dry period is crucial for the course of colostrogenesis. The colostrum synthesis is determined by the nutrition during the prepartum period, but the transfer of Ig is obviously independent of nutritional influences. The administration of conjugated linoleic acid during the dry period to dairy goats causes a less pronounced decrease of blood plasma IgG concentration (6%) but it did not change colostral IgG levels. In cattle, IgG1 is transported from blood into colostrum by an IgG1 specific receptor located on the surface of alveolar epithelial cells during colostrogenesis, and this is most likely similar in small ruminants. Via inactivation of this receptor, the Ig transfer is downregulated by increasing prolactin (PRL) during lactogenesis. It was recently observed in goats treated with PGF2 alpha, in order to induce parturition, lower colostrum IgG concentrations occurred concomitantly with an earlier increase of plasma PRL as compared to untreated animals. The effect of litter size and number of lactations on colostral IgG concentration in small ruminants has not been made fully clear until now most likely due to the different breeds used in the published studies.

Changes in faecal bacteria and metabolic parameters in foals during the first six weeks of life

Many foals develop diarrhoea within the first two weeks of life which has been suggested to coincide with postpartum oestrus in their dams. To analyse the pathogenesis of this diarrhoea we have determined faecal bacteria in foals and their dams (n=30 each), and serum IGF-1 and gamma-globulins for 6 weeks after birth. In addition, effects of beta-carotene supplementation to mares (group 1: 1000 mg/day, n=15, group 2: control, n=15) on diarrhoea in foals were studied. Diarrhoea occurred in 92 and 79% of foals in groups 1 and 2, respectively, but was not correlated with oestrus in mares. Beta-carotene supplementation was without effect on foal diarrhoea. In mares, bacterial flora remained stable. The percentage of foals with cultures positive for E. coli was low at birth but increased within one day, the percentage positive for Enterococcus sp. was low for 10 days and for Streptococcus sp. and Staphylococcus sp. was low for 2-4 weeks. By 4 weeks of age, bacterial flora in foals resembled an adult pattern. Concentration of serum IGF-1 was low at birth (group 1: 149 +/- 11, group 2: 166 +/- 17ng/ml), increased after day 1 (day 7 group 1: 384 +/- 30, group 2: 372 +/- 36) but at no time differed between groups. Serum gamma-globulin concentration in foals was low before colostrum intake and highest on day 1 (p<0.001 over time). In conclusion, neonatal diarrhoea in foals does not coincide with postpartum oestrus in their dams but with changes in intestinal bacteria and is not influenced by beta-carotene supplementation given to mares.