References of "Theron, Léonard"
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See detailCarnet Clinique de Médecine de Troupeau
Guyot, Hugues ULg; Theron, Léonard ULg; Frisee, Vincent ULg et al

Book published by ULG - FMV - DCP - 4ème édition (2014)

L’agriculture évolue, la médecine vétérinaire suit le même chemin. Les troupeaux d’hier ressemblent de moins en moins à ceux d’aujourd’hui. Hier, la médecine vétérinaire se concentrait sur l’urgence et ... [more ▼]

L’agriculture évolue, la médecine vétérinaire suit le même chemin. Les troupeaux d’hier ressemblent de moins en moins à ceux d’aujourd’hui. Hier, la médecine vétérinaire se concentrait sur l’urgence et donc le cas individuel. Dès aujourd’hui, et encore plus demain, il faut voir l’individu dans sa globalité et donc dans son troupeau. L’unité épidémiologique n’est plus l’individu mais le troupeau. La médecine devient davantage préventive que curative. De là est né le concept Herd Health & Production Management (HH&PM) alliant à la fois des mesures préventives et curatives dans le but d’améliorer la productivité et la rentabilité du troupeau. Cette forme de médecine garde toutefois à l’esprit les attentes du consommateur en termes de qualité des denrées alimentaires d’origine animale (résidus, qualités organoleptiques et microbiologiques) et de bien-être animal. Le concept HH&PM peut se définir comme « l’expression maximale du potentiel génétique d’un animal individuel et du troupeau comme un tout, en optimisant le management de l’exploitation, ainsi que les conditions de la ferme et en conséquence, les entrées économiques de la ferme ». L’examen global d’un troupeau requiert toutefois des connaissances élargies : alimentation, médecine, thériogénologie, bioclimatologie, parasitologie, bactériologie, épidémiologie, économie, zootechnologie. Il est essentiel de ne pas segmenter ses connaissances à l’approche du troupeau tant les problèmes rencontrés peuvent être multifactoriels. La 4ème édition de ce carnet clinique se veut toujours plus pratique et calquée sur le modèle des visites HH&PM que le Département Clinique des Animaux de Production (DCP) de l’Université de Liège réalise quotidiennement sur le terrain. De nombreux rappels sont proposés ainsi que des pistes et/ou canevas permettant d’appréhender au mieux une problématique de troupeau. Cependant, il est très difficile d’être exhaustif pour un carnet de poche (cet outil est avant tout un aide-mémoire en exploitation) et le lecteur prendra soin de compléter ses connaissances dans les livres/cours ad hoc. Par ailleurs, les informations contenues dans ce carnet ne sont pas fixées une fois pour toutes. Les législations, normes, spécialités pharmaceutiques peuvent évoluer et le détenteur de ce carnet clinique de médecine de troupeaux veillera à se tenir informé de ces modifications potentielles. Enfin, bien que les normes établies constituent des repères objectifs, le praticien sera attentif à ne pas émettre de jugement ou diagnostic définitif sur base de simples normes, mais analysera la situation dans sa globalité, en tenant compte de l’aspect clairement multifactoriel des maladies de production dans les élevages bovins laitiers ou viandeux. Enfin, j’adresse mes remerciements aux Profs Emile Bouchard et Luc DesCôteaux, (Université de Montréal, St-Hyacinthe Québec, Canada), et leurs collaborateurs, au Dr. Virginie Filteau (DSAHR Inc., Québec, Canada), à mes collègues du DCP et de la FMV, et à MSD pour l’inspiration, l’impulsion et l’aide à la réalisation de ce carnet clinique. Pour l’Equipe, Pr. Hugues Guyot 4ème édition – Liège – Janvier 2014 Editions précédentes : 1ère édition (2002), 2ème édition (2006), 3ème édition (2011) [less ▲]

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See detailEvaluating somatic cell scores with a Bayesian Gaussian linear state-space model.
Detilleux, Johann ULg; Theron, Léonard ULg; Reding, E. et al

in Animal : an international journal of animal bioscience (2014), 8(3), 477-83

Because accurate characterization of health state is important for managing dairy herds, we propose to validate the use of a linear state-space model (LSSM) for evaluating monthly somatic cell scores ... [more ▼]

Because accurate characterization of health state is important for managing dairy herds, we propose to validate the use of a linear state-space model (LSSM) for evaluating monthly somatic cell scores (SCSs). To do so, we retrieved SCS from a dairy database and collected reports on clinical mastitis collected in 20 farms, during the period from January 2008 to December 2011 in the Walloon region of Belgium. The dependent variable was the SCS, and the independent variables were the number of days from calving, year of calving and parity. The LSSM also incorporated an error-free underlying variable that described the trend across time as a function of previous clinical and subclinical status. We computed the mean sum of squared differences between observed SCS and median values of the posterior SCS distribution and constructed the receiver operating characteristic (ROC) curve for SCS thresholds going from 0 to 6. Our results show SCS estimates are close to observed SCS and area under the ROC curve is higher than 90%. We discuss the meaning of the parameters in light of our current knowledge of the disease and propose methods to incorporate, in LSSM, this knowledge often expressed in the form of ordinary differential equations. [less ▲]

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See detailComprendre la mammite bovine comme une enzootie dynamique
Theron, Léonard ULg; Hanzen, Christian ULg

Article for general public (2013)

Health disorders in bovine herds are, in essence, multifactorial. They are based on the equilibrium among various factors. The major difficulty in managing endemias in livestock production emerges from ... [more ▼]

Health disorders in bovine herds are, in essence, multifactorial. They are based on the equilibrium among various factors. The major difficulty in managing endemias in livestock production emerges from two elements: the extreme variability of practices among farms and over time on one hand and on the other hand, the crossed impact of various factors producing the same result. A simple example will illustrate the two problems: Mastitis has epidemiological components that govern their own response to means of prevention. Because no two dairy farms ever have fifty per cent of their livestock production practices in common, the establishment of the usual means of prevention will never have the same dosable impact in each of the two farms (Bradley et al. 2007; Théron et al. 2009). Further, in view of the variability of certain practices or adjustments over time, a situation can vary while all other factors remain constant, due to a neglected invisible factor, thus diminishing the strength of the prevention argument. Each of us has known situations in which post-dipping did not generate the anticipated effects, and situations in which, after a transitory improvement linked to milking practices, the situation degrades again for a cause associated with the milking machine or feeding. The conclusion of this introduction is both simple and complex: the integrated control of mastitis is based on long-term monitoring. This monitoring is justified by the economic and societal impact of this disease. Good monitoring implies the definition of key measurable control points. The aim of this article will be to define the indicators and epidemiological objectives that enable the level of mammary health and its evolution to be defined over time. [less ▲]

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See detailAnalyse de l'efficience des traitements de mammites de 50 fermes de Wallonie dans la base LAECEA
Theron, Léonard ULg; Reding, Edouard; Detilleux, Johann ULg et al

Conference (2013, October 11)

Mastitis is the most “antibiotic consuming” pathology in dairy medicine. Though antibiotics and antibiograms are known to vets since the early fifties, our practices did not evolved a lot from empiric ... [more ▼]

Mastitis is the most “antibiotic consuming” pathology in dairy medicine. Though antibiotics and antibiograms are known to vets since the early fifties, our practices did not evolved a lot from empiric antibiotic therapy. Indeed, the need for a treatment, the cost and the delay for an antibiogram are most of the time incoherent with a routine practice. Nevertheless, there is a surge for rational use of antibiotics. Our study was based on 1100 mastitis events from 30 Belgian farms collected between January 2011 and June 2012. We chose to compare tissular cure (TC) based on the threshold of 200.000 somatic cells/ml in milk at milk control at least 60 days after the clinical mastitis event. Regarding the mastitis event, severity (according 3 grades: alteration of milk as grade 1, alteration of quarter as grade 2 and alteration of general state as grade 3), quarter, treatments were recorded. We also assessed a chronicity status based on previous somatic cell count (SCC) of the cow. It was considered a new case a cow which at least 15 days before had an SCC <200.000 cells/ml, other were marked as chronic cases. In our distribution, we see a seasonal rise of incidence between January and May. This period would represent twice as many mastitis as the summer period. Overall TC reaches 46% of all mastitis events, which is quite poor. Rear quarters had significantly lower TC (p<0,05%). Grade 3 mastitis had lower TC, 42,6% (p<0.05%) versus 48,9 % for grade 2 and 44,2% for grade 1. Almost 49% of all mastitis was considered as chronic cases, which TC was 33% on average, whereas new cases reached 55,3% TC. Study of treatment was frustrating given the high number of different combinations of treatments. It was underlined that 4th generation cephalosporins (C4G) were the most used in our cohort, followed by aminopenicillin/methicillin association (PENA/PENM) and 1st generation cephalosporins/aminoglycosids (C1G/AG) association. Of these intramammary treatments, 20% of the cases were submitted to a second intramammary drug, mostly C1G or C1G/AG. One third of the cases were treated parenterally with antimicrobials, mostly macrolids, fluoroquinolones and penethacillin. Finally, 10% of mastitis was treated with anti-inflammatory drugs, mostly tolfenamic acid and flunixin-meglumin. Comparing mastitis without use of a secondary intramammary drug, only PENA and C1G/AG reached more than 60% TC. Considering new cases, then C1G/AG, PENA/PENM and Prednisolone containing specialties were above 60% TC. Use of a parenteral injections increased TC only on new cases (+12%), but not on chronic cases. Refining by severity, TC improved with a parenteral on new cases, mainly in grade 1 (+20%). Regarding associated factors, TC was negatively affected by chronicity, parity and lactation stage. Indeed, TC was lower on cases from more than 4 month in milk, third lactation (OR = 2.8 for no cure) compared with previous, and chronic cases (OR=2,6). Seemingly, chronicity was positively associated with parity and season. The 3rd parity cases had higher chances to be chronic ones (OR = 1,7), as well as cases from April to September (OR = 1,6). This evaluation of cure is rather simple and has a good variability which allows several questions about the real match between antimicrobial treatment for mastitis and the udder inflammation. Based on our epidemiological data, we can modify routine management of mastitis, as some cases might not worth the antimicrobial treatment. [less ▲]

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See detailFluidothérapie chez le veau
Sartelet, Arnaud ULg; Lecomte, Denis; Theron, Léonard ULg et al

Conference (2013, September 27)

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See detailField Investigation of subacute ruminal acidosis in Walloon dairy herds
Lessire, Françoise ULg; Knapp, Emilie ULg; Theron, Léonard ULg et al

in Universität Bern (Ed.) Proceedings of 8th ECBHM (2013, August 28)

Subacute ruminal acidosis (SARA) has been considered as a major metabolic disease in high producing dairy herds for years. For instance, out of 737 cows from Wisconsin farms, 20% exhibited ruminal pH ... [more ▼]

Subacute ruminal acidosis (SARA) has been considered as a major metabolic disease in high producing dairy herds for years. For instance, out of 737 cows from Wisconsin farms, 20% exhibited ruminal pH values lower than 5.5, allowing diagnosis of SARA, while 23% of animals were considered at risk with ruminal pH values between 5.5 and 5.8. These findings were corroborated by further studies in Europe. However, different feeding practices and herd’s production levels are found in Wallonia, requiring evaluation of SARA prevalence in local herds. [less ▲]

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See detailHAEMATOLOGICAL PROFILES OF CALVES BELONGING TO HERDS WITH BOVINE NEONATAL PANCYTOPENIA HISTORY IN AND AROUND WALLONIA (BELGIUM).
Ronzoni, Anna ULg; Theron, Léonard ULg; Bayrou, Calixte ULg et al

in Buiatrissima, 8th ECBHM Symposium, 28-30 August 2013, Bern, Proceedings (2013, August)

The objective of the present study was to verify the hypothesis of subclinical BNP cases, by random sampling and haematological analysis in different herds with BNP history, in order to obtain a better ... [more ▼]

The objective of the present study was to verify the hypothesis of subclinical BNP cases, by random sampling and haematological analysis in different herds with BNP history, in order to obtain a better epidemiological picture of this disease. [less ▲]

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See detailGetting insights on bovine mastitis treatment efficacy based on tissular indicators with an integrated udder health management file: Project LAECEA.
Theron, Léonard ULg; Reding, Edouard; Rao, Anne-Sophie ULg et al

Poster (2013, August)

Mastitis is the most “antibiotic consuming” pathology in dairy medicine. Though antibiotics and antibiograms are known to vets since the early fifties, our practices did not evolved a lot from empiric ... [more ▼]

Mastitis is the most “antibiotic consuming” pathology in dairy medicine. Though antibiotics and antibiograms are known to vets since the early fifties, our practices did not evolved a lot from empiric antibiotic therapy. Indeed, the need for a treatment, the cost and the delay for an antibiogram are most of the time incoherent with a routine practice. Nevertheless, there is a surge for rational use of antibiotics. Our study was based on 1100 mastitis events from 30 Belgian farms collected between January 2011 and June 2012. We chose to compare tissular cure (TC) based on the threshold of 200.000 somatic cells/ml in milk at milk control at least 60 days after the clinical mastitis event. Regarding the mastitis event, severity (according 3 grades: alteration of milk as grade 1, alteration of quarter as grade 2 and alteration of general state as grade 3), quarter, treatments were recorded. We also assessed a chronicity status based on previous somatic cell count (SCC) of the cow. It was considered a new case a cow which at least 15 days before had an SCC <200.000 cells/ml, other were marked as chronic cases. In our distribution, we see a seasonal rise of incidence between January and May. This period would represent twice as many mastitis as the summer period. Overall TC reaches 46% of all mastitis events, which is quite poor. Rear quarters had significantly lower TC (p<0,05%). Grade 3 mastitis had lower TC, 42,6% (p<0.05%) versus 48,9 % for grade 2 and 44,2% for grade 1. Almost 49% of all mastitis was considered as chronic cases, which TC was 33% on average, whereas new cases reached 55,3% TC. Study of treatment was frustrating given the high number of different combinations of treatments. It was underlined that 4th generation cephalosporins (C4G) were the most used in our cohort, followed by aminopenicillin/methicillin association (PENA/PENM) and 1st generation cephalosporins/aminoglycosids (C1G/AG) association. Of these intramammary treatments, 20% of the cases were submitted to a second intramammary drug, mostly C1G or C1G/AG. One third of the cases were treated parenterally with antimicrobials, mostly macrolids, fluoroquinolones and penethacillin. Finally, 10% of mastitis was treated with anti-inflammatory drugs, mostly tolfenamic acid and flunixin-meglumin. Comparing mastitis without use of a secondary intramammary drug, only PENA and C1G/AG reached more than 60% TC. Considering new cases, then C1G/AG, PENA/PENM and Prednisolone containing specialties were above 60% TC. Use of a parenteral injections increased TC only on new cases (+12%), but not on chronic cases. Refining by severity, TC improved with a parenteral on new cases, mainly in grade 1 (+20%). Regarding associated factors, TC was negatively affected by chronicity, parity and lactation stage. Indeed, TC was lower on cases from more than 4 month in milk, third lactation (OR = 2.8 for no cure) compared with previous, and chronic cases (OR=2,6). Seemingly, chronicity was positively associated with parity and season. The 3rd parity cases had higher chances to be chronic ones (OR = 1,7), as well as cases from April to September (OR = 1,6). This evaluation of cure is rather simple and has a good variability which allows several questions about the real match between antimicrobial treatment for mastitis and the udder inflammation. Based on our epidemiological data, we can modify routine management of mastitis, as some cases might not worth the antimicrobial treatment. [less ▲]

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See detailField investigation of subacute rumen acidosis prevalence in walloon dairy herds
Lessire, Françoise ULg; Knapp, Emilie ULg; Theron, Léonard ULg et al

Poster (2013, June 24)

Subacute ruminal acidosis (SARA) has been considered as a major metabolic disease in high producing dairy herds for years. However, different feeding practices However, different feeding practices and ... [more ▼]

Subacute ruminal acidosis (SARA) has been considered as a major metabolic disease in high producing dairy herds for years. However, different feeding practices However, different feeding practices and herd’s production levels are found in Wallonia. SARA prevalence in local herds was thus required 174 cows (164 Holstein and 10 Brown Swiss) out of 24 walloon herds were sampled from 2011 to 2012 for evaluation of their ruminal function. Selection of minimum 5 cows per herd was made on basis of days in milk (<150 DIM), or low milk fat % (F <3.2%), or fat/protein % (F/P≤1), or at farmer’s request (animal debilitated or chronically ill). Ruminal fluid was sampled 4-8 h after feeding using a Geishauser oro-pharyngeal probe, preventing saliva contamination. pH was measured by a portable pHmeter and values were reduced by 0.35 as proposed by Duffield (2004) because of the higher pH values in reticulum sampling site compared with rumenocentesis. Redox potential was determined by Methylene Blue Reduction Time (MBRT) and protozoa assessed by microscopy. Production values were obtained by the National Dairy Herds Improvement. Health scores were determined as described by Zaaier et al. (2001). RESULTS Mean production values ± SD of these animals (DIM: 106 ± 84) were 33.2 ± 8.9 kg milk, F = 3.47 ± 0.72%, P = 3.25 ± 0.25%, F/P = 1.07 ± 0.23. Mean BCS was 2.6 ± 0.6. Mean pH value ± SD was 6.50 ± 0.42. 10 animals (5.7%) from 6 herds were below 5.8, of which 4 cows from H8 (23 sampled cows). No result was < 5.5. MBRT was 4.16 ± 3.13 min. In 5 cows, value < 1min indicated a more amylolytic bacterial flora. In 24 samples, no reduction of MB occurred, demonstrating bacterial inactivity. Disappearance of large protozoa was observed in 6 samples, of which 5 abnormal specimens came from H8. No correlation between low pH values and F/P or %F could be found. CONCLUSION In no herd, prevalence was >25%, required for SARA diagnosis. Regarding these results, prevalence of SARA appears very low in Wallonia while on the opposite, ruminal flora inactivity seems far more common. [less ▲]

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See detailInvestigation of biological markers to evaluate the adaptation of the newborn Belgian Blue calf to the extrauterine life. A pilot study.
Ronzoni, Anna ULg; Theron, Léonard ULg; De Marchin, Emmanuelle et al

in Dalin, Göran (Ed.) 15th International Conference on Production Diseases in Farms Animals, Book of Abstracts (2013, June)

Adaptation to extrauterine life and immunity transfer at calving are more at stake when dealing with highly productive breeds such as the Belgian Blue Cattle Breed (BBCB). The purpose of the present pilot ... [more ▼]

Adaptation to extrauterine life and immunity transfer at calving are more at stake when dealing with highly productive breeds such as the Belgian Blue Cattle Breed (BBCB). The purpose of the present pilot study was to evaluate different blood markers, from the birth to the first week of life in BBCB calves, in order to investigate fundamental aspects of the adaptation to the extrauterine life as passive immunity transfer and early energy metabolism. Eighty calves coming from 10 different farms located in Wallonia (Belgium) were enrolled. A clinical examination was performed to verify viability and maturity at birth. Blood samples were collected at birth, day 1 and day 3 to 7. Passive immunity transfer analysis included serum and colostrum immunoglobulin G (IgG) concentration, and plasmatic selenium concentration (Se). Glycemia, serum insulin and cortisol concentration have been considered for the energy metabolism analysis. The data collected were statistically analysed using logistic regression and unpaired t-test. All calves were born alive, viable and mature by caesarean section. Mortality rate was 0% at one week and 5% at three months. Only 33% of calves had an IgG concentration >16g/L after one week of age, while only 34% of colostra had an IgG concentration >70g/L. Glycemia and serum insulin concentration at birth were significantly lower than other breeds, and plasmatic selenium concentration were coherent with low supplemented dams. We compared calves across IgG concentration classes (>16 g/L vs <16g/L). The crosssectional analysis of the risk of FPT when given low IgG concentration colostra has shown a non significant odd ratio (OR 1,058 and 0,39116 g/L) (p<0,001). No significant difference has been shown between cortisol and glycemia (p=0,3) nor insulin and glycemia (p=0,2) at birth. These data suggest a significant difference in BBCB calves on several metabolic markers, but they also revealed that immunity transfer and micronutrition of pregnant hyper-productive dams remain a challenge in modern farms. [less ▲]

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See detailQuels facteurs de réussite pour le tarissement
Theron, Léonard ULg; Hetreau, Thierry

Conference given outside the academic context (2013)

Comprendre les différentes implications zootechniques et thérapeutiques du tarissement des vaches laitières permet de prévoir les facteurs de réussite de cette période, tant au point de vue sanitaire que ... [more ▼]

Comprendre les différentes implications zootechniques et thérapeutiques du tarissement des vaches laitières permet de prévoir les facteurs de réussite de cette période, tant au point de vue sanitaire que métabolique [less ▲]

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See detailMammites suraigues : Quel diagnostic différentiel, Quels germes peuvent jouer un rôle?
Theron, Léonard ULg; Hanzen, Christian ULg

Conference given outside the academic context (2013)

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See detailTarir nos vaches laitières en 2013 : Comprendre, Depister, Prévenir
Theron, Léonard ULg; Hanzen, Christian ULg

Conference given outside the academic context (2013)

Tarir ses vaches laitières hautes productrices de nos jours demeure un défi, de part le niveau de production, les pathologies puerpérales liées, et la compréhension de la dynamique d’infection au ... [more ▼]

Tarir ses vaches laitières hautes productrices de nos jours demeure un défi, de part le niveau de production, les pathologies puerpérales liées, et la compréhension de la dynamique d’infection au tarissement. Au travers d'exercices choisi, d'analyse des données d'élevage, les participants seront amenés à décrire la situation d'élevage, et les facteurs de risque investiguables par le praticien. [less ▲]

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See detailStructural esuation models to estimate risk infection and tolerance to bovine mastitis
Detilleux, Johann ULg; Theron, Léonard ULg; Duprez, Jean-Noël ULg et al

in Genetics, Selection, Evolution (2013), 45

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See detailL’urovagin chez la vache laitière. Proposition d’une méthode de correction chirurgicale.
Hanzen, Christian ULg; Rao, Anne-Sophie ULg; Theron, Léonard ULg et al

in Bulletin des Groupements Techniques Vétérinaires (2013), 69

L’urovagin constitue une affection relativement fréquente de la vache laitière (10.7 à 26.7 % des vêlages). Un simple examen vaginal au moyen d’un vaginoscope permet d’en distinguer trois degrés selon le ... [more ▼]

L’urovagin constitue une affection relativement fréquente de la vache laitière (10.7 à 26.7 % des vêlages). Un simple examen vaginal au moyen d’un vaginoscope permet d’en distinguer trois degrés selon le volume d’urine accumulée sur le plancher vaginal. Son apparition est liée au relâchement du muscle du vestibule vulvo-vaginal mais dépend également de la position horizontale de la vulve, de la diminution du score corporel dont la valeur est inférieure à 2,75 au cours du mois suivant le vêlage et de la présence d’une endométrite durant la période d’attente. Les degrés 2 et 3 constituent des facteurs directs et indirects d’infertilité et d’infécondité étant donné leur effet favorisant sur l’apparition d’endométrite après le 60ème jour du postpartum. L’urovagin de degré 1 peut régresser spontanément. Les urovagins de degré 2 et 3 doivent être traités par voie chirurgicale (urétroplastie ou cerclage) ou non chirurgicale (ozone). [less ▲]

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See detailAnalyse de l'efficience des traitements de mammites de 60 fermes de Wallonie dans la base LAECEA
Theron, Léonard ULg; Reding, Edouard; Detilleux, Johann ULg et al

in Brard, Christophe (Ed.) Recueil des Journées Nationale des GTV (2013)

Le traitement de la mammite bovine est un acte à part dans la routine d’une exploitation bovine. En effet, si les cas les plus graves sont vus presque systématiquement pas le vétérinaire traitant en ... [more ▼]

Le traitement de la mammite bovine est un acte à part dans la routine d’une exploitation bovine. En effet, si les cas les plus graves sont vus presque systématiquement pas le vétérinaire traitant en France ou en Belgique, la plupart des cas peu sévères font l’objet d’une tacite délégation de diagnostic et de traitement, sur base d’une formation préalable et d’une prescription enregistrée. Aujourd’hui, cette pathologie représente le plus important poste de consommation d’antibiotiques en exploitation laitière. Concernant cette problématique, la profession vétérinaire doit disposer de nouveaux outils de diagnostic, de traitement, et surtout d’évaluation de la qualité du traitement. Or, depuis la fin des années 1940, la pratique de l’antibiothérapie est restée, comme en médecine humaine, basée essentiellement sur l’antibiothérapie empirique, plus ou moins régulée par des cultures bactériologiques et des antibiogrammes (Durel et al., 2012). La profession s’est dotée d’outils d’analyse épidémiologique et clinique au cours des décennies, mais les résultats sont mitigés : une diminution globale de la consommation d’antibiotiques, mais le recours accru à des classes de dernières générations. Aujourd’hui le grand enjeu de l’antibiothérapie se corse, avec l’identification de mécanisme de résistance suspects d’être communs avec la médecine humaine(Jaglic et al., 2010). Plusieurs classes de molécules communes avec la médecine humaine sont identifiées, et leur utilisation menace d’être régulée (Bagcigil et al., 2007). Face à ce constat, l’utilisation des antibiotiques destinés au traitement de la mamelle a été étudiée en Belgique, dans soixante fermes laitières wallonnes (Théron et al., 2011). [less ▲]

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See detailGestion de la reproduction dans les troupeaux bovins laitier
Hanzen, Christian ULg; Rao, Anne-Sophie ULg; Theron, Léonard ULg

in Revue Africaine de Santé et de Productions Animales [=RASPA] (2013)

La décision de la commission européenne de mettre fin en 2015 à la politique des quotas laitiers mise en place en 1984 va vraisemblablement bousculer le paysage laitier européen mais aussi mondial. Plus ... [more ▼]

La décision de la commission européenne de mettre fin en 2015 à la politique des quotas laitiers mise en place en 1984 va vraisemblablement bousculer le paysage laitier européen mais aussi mondial. Plus que jamais les grands pays producteurs (Etats-Unis, Canada, France, Allemagne, Pays-Bas, Irlande, Nouvelle-Zélande) vont dans ce contexte de libéralisation et de globalisation de « l’or blanc » se livrer une concurrence effrénée dans laquelle la majorité des producteurs n’auront que peu ou rien à dire. L’augmentation attendue de la production laitière mondiale (15 milliards de litres par an entre 2010 et 2020) résulte bien entendu de l’augmentation de la population mondiale (3,1 milliards entre 1970 et 2010 auxquels s’ajouteront 2 milliards de plus en 2050) mais également du fait que davantage de personnes en Extrême et Moyen-Orient, en Amérique du Sud et en Afrique du Nord consomment davantage de lait et de produits dérivés. L’enjeu pour la majorité des éleveurs européens ou non va être de réduire les coûts liés à la production laitière en (1) optimisant les ressources alimentaires, (2) en améliorant la santé mammaire, (3) en augmentant la longévité des vaches, (4) en réduisant la fréquence des maladies métaboliques, locomotrices ou infectieuses et (5) en améliorant la fécondité. L’amélioration de la fécondité passe définition oblige par la réduction de l’âge du premier vêlage et de l’intervalle entre vêlages. Par gestion, il faut entendre dans un premier temps la quantification du problème et dans un second l’identification des diverses hypothèses diagnostiques qui en sont responsables. Les facteurs de nature alimentaire, thérapeutique, pathologique ou de gestion susceptibles de modifier l'évolution normale de chaque femelle depuis sa naissance jusqu'au moment de sa réforme sont de nature diverse. Ils concernent l'individu ou le troupeau. Ils sont directement ou indirectement responsables de leur fertilité et/ou de leur fécondité. Leurs effets se manifestent de manière isolée ou synergique. Ils concernent aussi bien les animaux que ceux qui en ont la responsabilité sanitaire ou de gestion. Ils sont de nature anatomique, infectieuse, hormonale, thérapeutique ou zootechnique. Par gestion de la reproduction, il faut entendre une approche épidémiologique, globale de l’infécondité qui en intègre les aspects spécifiques sans négliger pour autant les autres aspects qui ne lui sont pas directement liés. Par gestion de la reproduction, on peut aussi comprendre sa gestion hormonale à savoir le recours à des protocoles thérapeutiques de synchronisation des inséminations et donc des vêlages. L’une et l’autre approche s’inscrive dans le contexte d’une identification systématique des animaux à risque au travers d’un suivi mensuel de reproduction. Ce suivi est la clé de voûte d’une gestion de la reproduction. Au travers d’une démarche hypothético-déductive, la présente communication se propose de - quantifier les performances de reproduction au travers des ses principaux paramètres de fécondité et de fertilité : cette première étape est indispensable pour identifier la présence ou non d’un problème d’infécondité, - passer en revue et de manière aussi synthétique que possible les diverses hypothèses et donc les facteurs de risque responsables d’infécondité - proposer des stratégies curatives ou préventives, anti-infectieuses ou hormonales voire zootechniques pour limiter les conséquences de l’infécondité. [less ▲]

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