Actuellement en France et aux Etats-Unis, seules 30 à 35 % des premières inséminations artificielles chez la vache Holstein aboutissent à un vêlage. Les échecs de gestation ont lieu le plus souvent au cours du développement embryonnaire (Non-Fécondation-Mortalité Embryonnaire Précoce (NF-MEP) entre 0 et 16 jours, Mortalité Embryonnaire Tardive (MET) entre 16 et 45 jours après insémination). Ces échecs précoces de gestation expliquent en grande partie les différences de fertilité observées en France entre la race Holstein et les autres races plus fertiles. Les facteurs de risque de l'interruption de la gestation sont multiples : liés à l'animal, à l'environnement et à la conduite de l'élevage. Trois facteurs cependant ont évolué au cours du temps pour les vaches Holstein : le potentiel génétique, les anomalies de reprise de la cyclicité après vêlage, le déficit énergétique en début de lactation. Notre objectif a été d'identifier l'influence de ces trois facteurs sur les échecs précoces de gestation après première insémination postpartum chez la vache de race Holstein. Le potentiel génétique a été associé à l'incidence de NF-MEP et de MET. Les phases lutéales prolongées sembleraient être à l'origine d'une augmentation d'incidence de MET. Le déficit énergétique a eu un effet sur la NF-MEP et sur la MET. L'effet du déficit énergétique postpartum sur la qualité des ovocytes au moment de la mise à la reproduction reste hypothétique. Notre travail sur les échecs précoces de gestation a permis de contribuer à fournir des outils d'amélioration de conduite d'élevage aux professionnels. / Currently, in France and the United States of America, only 30-35 % of first artificial inseminations in Holstein cows result in a calving. Pregnancy failure mainly occurs during embryonic development (fertilization failure - early embryonic mortality (FF-EEM) between D0 and D16 or late embryonic mortality (LEM) between D16 and D45 after insemination). Early pregnancy failure explains the majority of the differences in fertility between the Holstein breed and the other breeds in France, which are more fertile. There are numerous risk factors which cause pregnancy failure: animal, environmental and farm management factors. There are however, three factors which have been modified over time in Holstein cows: genetic merit, abnormal patterns of resumption of cyclicity and negative postpartum energy balance (NEB). Our objective was to identify the relationships between these three factors and early pregnancy failure after first postpartum insemination in Holstein dairy cows. Genetic merit was related to the incidence of FF-EEM and LEM. Prolonged luteal phases seemed to increase the incidence of LEM. The NEB was associated with FF-EEM and LEM. The impact of NEB on oocyte quality during the breeding period remains unclear. Our early pregnancy failure studies have helped to provide some tools to improve farm management.

Condizioni meteorologiche e clima influenzano fortemente il settore delle produzioni animali. Lo stress da caldo determina una significativa riduzione dell'attività metabolica, della produzione, della capacità riproduttiva e una maggiore predisposizione alle malattie. Nel contesto biologico, la temperatura dell’aria è sicuramente considerata il principale fattore di stress, tuttavia, un’elevata umidità peggiora l'effetto della temperatura riducendo le perdite di calore per evaporazione e ostacolando quindi l’eliminazione del calore in eccesso. Scopi principali della ricerca sono stati la caratterizzazione dell’area del Mediterraneo in termini di Temperature Humidity Index (THI) e stabilire le relazioni tra stagione/THI e mortalità nella bovina da latte allevata in un’area geografica Italiana altamente vocata per questo tipo di allevamento. I risultati suggeriscono che, allevatori e politici che operano nell’area Mediterranea, dovrebbero tenere nella dovuta considerazione variabilità e scenari del THI nella pianificazione degli investimenti nel settore delle produzioni animali. Conoscere in anticipo il verificarsi di condizioni climatiche avverse permetterebbe agli allevatori di metter in atto misure di contrasto sugli effetti negativi delle condizioni climatiche. Inoltre, dovrebbero venire sviluppate misure di adattamento appropriate per contesti specifici in termini di cultura, società, o sistemi politici, che possano contribuire alla sostenibilità ambientale, nonché allo sviluppo economico e alla lotta alla povertà. / Weather and climate strongly influence the field of animal production. Heat stress causes a significant reduction in metabolic activity, production, reproductive capacity, and increases susceptibility to diseases. In the biological context, the air temperature is definitely considered the main factor of stress, however, high humidity worsens the effect of temperature by reducing the evaporation heat loss and thus preventing the removal of excess heat. The main purposes of the research were the characterization of the Mediterranean basin in terms of Temperature Humidity Index (THI) and to establish relationships between season/THI and mortality in dairy cattle bred in an Italian geographic area with a high concentration of dairy farms. THI variability and scenarios should be taken into careful consideration by farmers and policy makers operating in Mediterranean countries when planning investments. Investments should at least partially be directed to implementation of adaptation measures, which may support farmers in the transition to climate-smart agriculture and help them to alleviate the impact of hot extremes on animal welfare, performance and health. In addition, measures should be developed appropriate adaptation to the specific contexts in terms of culture, society, or political systems, which can contribute to environmental sustainability and economic development and fighting poverty.

A series of experiments were conducted to determine nutritional strategies to improve the efficiency of N utilization in dairy cows when feeding co-products including wheat-based (W-DDGS) and corn-wheat blend distillers grains with solubles (B-DDGS), and dried whey permeate (DWP). In Experiment 1, the objective was to determine the effects of replacing canola meal (CM) as the major protein source with W-DDGS on ruminal fermentation, microbial protein production, omasal nutrient flow, and animal performance. Cows were fed either a standard barley silage-based total mixed ration containing CM as the major protein supplement (0% W-DDGS, control) or diets formulated to contain 10, 15 and 20% W-DDGS (dry matter [DM] basis), with W-DDGS replacing primarily CM. Diets were isonitrogenous (18.9% crude protein [CP]). Inclusion of W-DDGS to the diet did not negatively affect ruminal fermentation, microbial protein production, and omasal nutrient flow. However, there was a 0.7- to 2.4-kg increase in DM intake, and a 1.2- to 1.8-kg increase in milk yield after the addition of W-DDGS in place of CM. In Experiment 2, the objective was to delineate the effects of including either W-DDGS or B-DDGS dried distillers grains with solubles as the major protein source in low or high CP diets fed to dairy cows on ruminal function, microbial protein synthesis, omasal nutrient flows, urea-N recycling, and milk production. The treatment factors were type of distillers co-product (W-DDGS vs. B-DDGS) and dietary CP content (15.2 vs. 17.3%; DM basis). The B-DDGS was produced from a mixture of 15% wheat and 85% corn grain. All diets were formulated to contain 10% W-DDGS or B-DDGS on a DM basis. Feeding up to 10% of dietary DM as B-DDGS or W-DDGS as the major source of protein did not have negative effects on metabolizable protein (MP) supply and milk production in dairy cows. However, reducing dietary CP content from 17.3 to 15.2% decreased milk production. This response was attributed to an insufficient supply of ruminally degradable protein (RDP) that suppressed microbial nonammonia N (NAN) synthesis in the rumen, thus decreasing intestinal MP supply. In Experiment 3, the objective was to determine the effects of replacing barley or corn starch with lactose (as DWP) in diets containing 10% W-DDGS on ruminal function, omasal nutrient flow, and lactation performance. The treatment factors were source of starch (barley vs. corn) and dietary inclusion level of DWP (0 vs. 6%; DM basis) as a partial replacement for starch. Diets were isonitrogenous (18% CP) and contained 3 or 8% total sugar. The starch content of the low sugar diet was 24% compared to 20% for the high sugar diet. Dry matter intake, and milk and milk component yields did not differ with diet. However, partially replacing dietary corn or barley starch with sugar up-regulated ruminal acetate and propionate absorption, and reduced ruminal NH3-N concentration, but had no effect on ruminal pH, microbial protein synthesis, omasal nutrient flow and production in dairy cows. In summary, data presented in this thesis indicate that W-DDGS and B-DDGS can be included as the major source of protein in dairy cow diets without compromising ruminal function, nutrient supply and milk production in dairy cows. Feeding medium to low CP diets, and partial replacement of starch with sugar in diets containing W-DDGS and B-DDGS can improve N utilization efficiency in dairy cows. Additionally, an upregulation of facilitated transport of acetate and propionate across epithelial cells possibly prevents the occurrence of ruminal acidosis when lactose partially replaces starch in cow diets.

Le développement et la survie de l’embryon dépendent des nutriments fournis par les sécrétions utérines. Les objectifs de cette étude étaient de déterminer l’effet de la surovulation (SOV) sur la bactériologie et cytologie utérine et sur les paramètres biochimiques utérin et sérique et leurs effets sur le nombre d’embryons transférables (ET). Deux groupes de vaches Holstein (groupe I, non lactante, n=7 et groupe II, lactante, n=28) ont été respectivement induites en chaleur ou surovulées et ensuite inséminées. Au jour 7 du cycle œstral (J7) et lors du jour de la récolte (JR), un prélèvement individuel de sang et de liquide de lavage utérin a été fait pour l’analyse du statut bactériologique et cytologique de l’utérus et la mesure de la concentration de plusieurs paramètres biochimiques présélectionnés. Les embryons récoltés ont été évalués selon les critères de l’IETS. La SOV a donnée une moyenne de 7.39 ± 6.22 ovocytes/embryons dont 3.32 ± 4.81 ET. Il n’y avait pas de variation significative de la bactériologie et cytologie utérine des deux groupes entre J7 et JR. La concentration sérique de l’urée (P=0.0001), d’E2 (P=0.006); la concentration utérine du Glu (P=0.002), de Ck (p=0.0007), de LDH (P <0.0001), de PT (P=0.004), de P4 (P=0.008), de PGFM (P<0.0001) du groupe I et la concentration sérique de P4 (P<0.0001), de PGFM (P<0.0001); la concentration utérine de LDH (P=0.002), de PGFM (P<0.0001) du groupe II ont été significativement élevées à JR qu’à J7. La concentration utérine et sérique de l’urée (P<0.0001 et P<0.0001), de LDH (P<0.0001 et P=0.008), la concentration sérique de P4 (P=0.0002) et la concentration utérine de PT (P=0.0003) à JR du groupe II étaient différente du groupe I. Il n’y avait pas d’association entre la bactériologie et cytologie utérine et le nombre d’ET. Cependant, le nombre d’ET a été positivement corrélé avec la concentration sérique d’IGF-1 à J7 (r=0.45; P=0.001) et la concentration sérique de P4 à JR (r=0.43; P<0.05) et négativement corrélé avec la concentration utérine et sérique de PGFM à la fois à J7 (r=-0.54; P<0.005 et r=-0.67; P<0.001) et à JR (r=-0.48; P<0.01 et r=-0.57; P<0.002). Ces résultats suggèrent que la SOV induit des changements au niveau sérique et utérin qui affectent le nombre d’ET récoltés. / The developing embryo is dependent on the nutrients provided by the oviduct and the uterine fluid. The objectives of this study were to determine the effect of SOV on uterine bacteriology and cytology, on serum and uterine biochemical parameters and consequently on the number of TE. Non-lactating (n=7) and lactating (n=28) Holstein cows were synchronized for estrus and superovulated respectively and were inseminated twice. Uterine bacteriology and cytology and various uterine and serum biochemical parameters were measured at day 7 of estrus cycle (D7, starting day of the SOV protocol) and at the designated day of embryo recovery (DER). Harvested embryos were evaluated according to IETS’s criteria. Superovulated cows produced an average of 7.39 ± 6.22 ova/embryos of which 3.32 ± 4.81 were TE. There were no significant variations of uterine bacteriology and cytology between D7 and DER within the two groups. Serum urea (P=0.0001), E2 (P=0.006); uterine Glu (P=0.002), Ck (P=0.0007), LDH (P<0.0001), TP (P=0.004), P4 (P=0.008), PGFM (P<0.0001) in group I and serum P4 (P<0.0001), PGFM (P<0.0001); uterine LDH (P=0.002), PGFM (P<0.0001) in group II were significantly higher at DER than at D7. At DER, group I was different to group II’ uterine and serum urea (P<0.0001 and P<0.0001), LDH (P<0.0001 and P=0.008), PGFM (P=0.002 and P=0.009), serum P4 (P=0.0002) and uterine TP (P=0.0003). There was no association between uterine bacteriology and cytology and the number of TE. However, TE was positively correlated with serum IGF-1 at D7 (r=0.45; P=0.001) and P4 at DER (r=0.43; P<0.05) and negatively correlated with both serum and uterine PGFM respectively at D7 (r=-0.54; P<0.005 and r=-0.67; P<0.001) and DER (r=-0.48; P<0.01 and r=-0.57; P<0.002). The present results infer that changes following SOV in both serum and uterine secretion may affect the number of TE.

Dans les élevages laitiers d’aujourd’hui, les déplacements de la caillette sont parmi les conditions chirurgicales les plus souvent rencontrées. Le pronostic pour ces pathologies est cependant très différent que l’on soit en présence d’une dilatation de la caillette à droite (DCD) ou d’un volvulus de la caillette (VC). En pratique, la distinction en période préopératoire entre ces deux conditions est difficile. Afin de limiter les pertes économiques associées aux DCD/VC, l’identification et la réforme précoce des animaux ayant le plus grand risque d’avoir une mauvaise évolution postopératoire deviennent des enjeux de premier plan. Les objectifs de cette étude étaient de déterminer la valeur pronostique de la L-lactatémie (LAC) mesurée à la ferme en préopératoire à l’aide d’un appareil portatif chez des vaches souffrant de DCD ou VC et de suggérer des seuils de LAC cliniquement significatifs. Nos résultats indiquent que la LAC est un bon indicateur pronostique lors de DCD/VC. Une LAC ≤ 2 mmol/L est un bon indicateur de succès chirurgical et s’avère très utile pour appuyer la décision d’opérer l’animal (sensibilité, spécificité, valeurs prédictives positive et négative de respectivement 76.2, 82.7, 53.3 et 93.1%). Par ailleurs, il n’y a aucun avantage économique à effectuer une chirurgie chez des vaches commerciales souffrant de DCD/VC qui ont une LAC ≥ 6 mmol/L (sensibilité, spécificité, valeurs prédictives positive et négative de respectivement 28.6, 97.5, 75 et 84%). Par conséquent, ces animaux devraient, dans la plupart des cas, être réformés en raison de la probabilité élevée qu’ils aient une mauvaise évolution postopératoire. / Abomasal displacement is among the most commonly encountered surgical disorder in modern dairy herds. Prognosis, however, varies widely among type of abomasal displacement, and preoperative diagnostic may be difficult to assess. To control the economic loss associated with abomasal disorders, especially right displaced abomasum (RDA) and abomasal volvulus (AV), early identification and culling of animals at higher risk of developing a surgical failure (SF) would be of interest. The objectives of this study were to determine the prognostic value of preoperative L-lactate concentration (LAC) measured on farm with a portable clinical analyzer for cows with RDA or AV, and to suggest LAC clinical relevant decision thresholds. Our results showed that LAC was correlated with the prognosis of RDA/AV. A LAC ≤ 2 mmol/L seemed to be good indicator of surgical success and would be useful to support a surgical decision (sensitivity, specificity, positive and negative predictive values of 76.2, 82.7, 53.3 and 93.1%; respectively). On the other hand, there is no economic advantage to perform a surgery on commercial cows with RDA/AV that have LAC ≥ 6 mmol/L and these animals should potentially be culled according to their high probability of SF (sensitivity, specificity, positive and negative predictive values of 28.6, 97.5, 75 and 84%; respectively).

In einer sächsischen Milchviehanlage mit etwa 1800 Milchkühen, deren Tankmilchzellzahl, infolge vermehrten Auftretens von Euterinfektionen mit S. aureus als Leitkeim längerfristig über 300.000 Zellen/ml aufwies, wurden zwei Vakzinen eingesetzt. Die Erwartungshaltung lautete, dass mit den Impfungen die Inzidenz- und Prävalenzraten von S. aureus- und KNS-bedingten Mastitiden bei Färsen und bei Kühen bis zur Geburt und auch danach sinken. Es wurde vor allem erwartet, dass bei den geimpften Tieren die Zellzahlen langfristig erniedrigt bleiben und sich folglich die Eutergesundheit durch die Vakzinationen verbessert. Anhand der Gesamtgemelkszellzahlen (GZZ) der letzten drei Milchleistungsprüfungen (MLP) a. p. und der zytobakteriologischen Befunde einer Beprobung auf Viertelebene wurden die Kühe (n=416) in Statusgruppen eingeteilt. In Statusgruppe 2 befanden sich eutergesunde Kühe (n=112). Tiere (n=146) mit moderat erhöhten Viertel- (VZZ) und GZZ, die auf mindestens einem Viertel bakteriologisch positiv waren, wurden in Statusgruppe 3 zusammengefasst. Die Statusgruppe 4 bildeten Kühe (n=158), die durch stark erhöhte GZZ und VZZ charakterisiert waren und ggf. bakteriologisch positiv waren. Färsen (n=181) wurden in Statusgruppe 1 zusammengefasst. Alle Tiere mussten klinisch gesund sein, Färsen sollten eutergesund erscheinen. Als Impfstoffe wurden Startvac® (HIPRA Deutschland GmbH, Düsseldorf), eine kommerzielle Vakzine gegen S. aureus, KNS, Escherichia coli und coliforme Keime, sowie eine bestandsspezifische Vakzine (Bestvac Rind Mastitis®, IDT Biologika GmbH, Dessau-Rosslau) basierend auf S. aureus-Isolaten aus Mastitismilchen des Bestandes eingesetzt. Nach dem Zufallsprinzip wurden die Tiere innerhalb der Statusgruppen den Impfgruppen oder der Kontrollgruppe zugeteilt. Die erste Vakzination wurde einen Tag nach dem Trockenstellen vorgenommen (bei Färsen an vergleichbaren Trächtigkeitstagen), die zweite Vakzination erfolgte ca. 31 Tage vor dem errechneten Kalbedatum. Um den 53. Tag p. p. fand die dritte Impfung statt. Zytobakteriologische Beprobungen aller Tiere auf Viertelebene wurden am Tag 5 sowie am Tag 52 p. p. vorgenommen. Außerdem wurden während der Laktation die monatlichen MLP-Daten sowie jene zu tierärztlichen Behandlungen der in der Studie befindlichen Kühe sowie Abgänge und Abgangsursachen erfasst. Innerhalb der Statusgruppen gab es zwischen den Vakzinationsgruppen und den Kontrolltieren bezogen auf die VZZ zu den Beprobungszeitpunkten 5 und 52 sowie auf die GZZ aus den MLPs der gesamten Laktation keine nennenswerten Unterschiede. Die Erregerprävalenzen zu den genannten Zeitpunkten nebst deren Verlauf und jene der zytobakteriologischen Diagnosen, erbrachten nur punktuell signifikante Unterschiede, die in der Summe aber keine anhaltende Tendenz erkennen ließen, die auf das bessere Abschneiden einer Vakzinationsgruppe im Vergleich zur Kontrollgruppe hindeuten würde. Zum gleichen Ergebnis gelangen die Auswertungen der Inzidenzraten, klinische Mastitisdaten und jene der Abgangsursachen im Anschluss an die Vakzinationen. Zusammenfassend hatte der Einsatz der bestandsspezifischen Vakzine Bestvac Rind Mastitis® sowie des Impfstoffes Startvac® mit EU-Zulassung bezogen auf die Zellzahlenentwicklung, die Inzidenz- und Prävalenzraten von S. aureus und KNS, die Behandlungsdauer und den Schweregrad von Mastitiden sowie die Heilungsraten im Vergleich zur Placebo-Gruppe in keiner der Statusgruppen erkennbare positive Effekte auf die Eutergesundheit.

Au cours des dernières décennies, une dégradation de la fertilité des vaches laitières, parallèlement à une augmentation de la production laitière a été observée. Des régions du génome, les QTL, affectent la fertilité femelle. Le but de ce travail de thèse est d’étudier la fertilité et certains paramètres zootechniques chez des vaches Prim'Hosltein en première lactation choisies pour leur haplotype favorable "fertil+" ou défavorable "fertil-" pour un QTL de fertilité situé sur le chromosome 3. Ce phénotypage a montré une meilleure fertilité et un meilleur bilan énergétique dans la première semaine de lactation pour les vaches "fertil+" par rapport aux vaches "fertil-". De plus, les vaches "fertil-" ont un flux d’ingestion plus rapide. Au pic de mobilisation, certains gènes du QTL étaient différentiellement exprimés dans le tissu adipeux des deux haplotypes. Dans les cellules de la granulosa, un de ces gènes, nommé Kirrel, est plus exprimé chez les vaches "fertil+" et sa protéine recombinante inhibe la sécrétion de progestérone in vitro. Notre travail a permis d'affiner les interactions génotype-phénotype liées à un QTL de fertilité et de mettre en avant un des possibles rôles d'un gène de ce QTL dans la fonction de reproduction chez la vache laitière. / In recent decades, the dairy cow fertility has declined, in parallel with an increase in milk production. Some regions of the genome, named QTL, affect female fertility. The purpose of this thesis is to study fertility and some zootechnical parameters in Prim'Hosltein cows in first lactation chosen for their favorable haplotype "fertil+" or unfavorable haplotype "fertil-" for one fertility QTL on chromosome 3. This phenotyping showed better fertility and energy balance in the first week of lactation for "fertil+" than for "fertil-" cows. In addition, "fertil-" cows had a higher eating rate. At the peak of mobilization, the QTL genes are differentially expressed in adipose tissue of "fertil+" and "fertil-" cows. In granulosa cells, one of these genes, named Kirrel, is higher expressed in "fertil+" cows and its recombinant protein inhibits the secretion of progesterone in vitro. Our work has contributed to refine interactions genotype-phenotype linked to one fertility QTL and highlighted one of the possible roles of a gene which belongs to this QTL in the reproductive function in dairy cows.

No description available.

The biofilm-associated protein (Bap) of Staphylococcus aureus is a high molecular weight cell-wallanchored protein involved in biofilm formation, first described in bovine mastitis strains from Spain. So far, studies regarding Bap were mainly based on the Spanish strain V329 and its mutants, but no information on the genetic variability of bap-positive Staph. aureus strains is yet available in the literature. The present study investigated the molecular characteristics of 8 bap-positive Staph. aureus strains from subclinical bovine mastitis, isolated in 5 herds; somatic cell counts (SCC) of milk samples were also registered. Strains were characterised using MLST, SPA typing and microarray and the results were compared with V329. All isolates from this study and V329 were assigned to ST126, t605, but some molecular differences were observed. Only herd A and B strains harboured the genes for β-lactams resistance; the leukocidin D/E gene, a type I site-specific deoxyribonuclease subunit, 3rd locus gene and serin-protease A and B were carried by all strains, but not by V329, while serin-protease E was absent in V329 and in another isolate. Four isolates and V329 harboured the fibronectin-binding protein B gene. SCC showed the highest value in the milk sample affected by the only strain carrying all the virulence factors considered. Potential large variability of virulence was evidenced among V329 and all bap-positive Staph. aureus strains considered: the carriage of fnb could enhance the accumulation of biofilm, but the lack of lukD/E and splA, B or E might decrease the invasiveness of strain.

The diploma thesis is dealing with the determination of caseins in lyophilised samples of milk using the method of capillary electrophoresis (CE). This method was optimised and verified by Ivana Micikova in her diploma thesis in 2009. The theoretical part of the diploma thesis gives information about the chemical compound of cow's milk. Caseins and their usage in the food and non-food industries are described in a separate unit. Impact of both the nutritional and non-nutritional factors on the composition of the milk is discussed further. The description and the principles of the CE and a list of the methods of CE used in the last several years are stated at the end of this part. The experimental part is focused on the preparation of the solutions, process of casein isolation and its analysis. It summarises the setting of the experiment, sampling and sample processing and the composition of the feeding mixtures. The diploma thesis has arisen on the basis of the cooperation of the Institute of Food Science and Biotechnology, the Faculty of Chemistry, Brno University of Technology and the Research Institute for Cattle Breeding, Ltd., Department of Animal Nutrition Physiology in Pohorelice.