The impact of lactate producing direct-fed microbial (DFM) on growth performance and rumen fermentation in beef cattle was explored in four studies. Experiment 1 studied the interaction between DFM and degradable intake protein (DIP) supply in receiving cattle. No differences (P≥0.06) in intake, morbidity, or immune response were observed; however, during the first 28 d gain and efficiency responses to DFM were dependent on DIP (DIP×DFM P≤0.05). Experiment 2 showed that in vitro gas production and select endpoint metabolites differed (P≤0.04) with DFM application. Experiment 3 compared lactate producing DFM to a lactate producing/utilizing DFM in finishing cattle. No differences (P≥0.14) in intake, gain, efficiency, or carcass characteristics were observed between control and lactate DFM; however, gain and growth efficiency differed (P≤0.05) between the lactate producing and lactate producing/utilizing DFM during the later portions of feeding. Experiment 4 studied the impact of DFM on ruminal fermentation, lactate utilization, and total tract digestibility. Ruminal pH and molar proportions of acetate were increased (P≤0.05) with DFM; however, lactate utilization and total tract digestibility did not differ (P≥0.33). The studies suggest that DFM improve growth performance during receiving and responses are at least partly mediated through differences in ruminal fermentation.

Endophyte-infected (E+) tall fescue grass has been associated with fescue toxicosis, a costly syndrome characterized by poor cattle performance and health resulting in significant production losses. The fungal endophyte produces ergot alkaloids, which help the grass thrive in poor conditions but are toxic to mammals. A number of symptoms of fescue toxicosis can be related to vasoconstriction of bovine core, peripheral, and foregut vasculature. The first part of this series of experiments demonstrated ergot alkaloids were also vasoactive in midgut vasculature, with the exception of lysergic acid. Additionally, prior dietary exposure to ergot alkaloids decreased the contractile response of mesenteric vasculature to many of the ergot alkaloids tested. In the second part of this series, a non-invasive method was developed for measuring rumen motility in cannulated cattle. Using this technology without different dietary treatments, it was determined that 8 to 16 h after feeding was the least variable between animals and would provide the best opportunity to measure differences in motility. Application of this technique in the third part of this series investigated the effect of ruminally dosed ergot alkaloids on rumen motility. Treatments were not effective at inducing fescue toxicosis, and no differences in rumen motility variables were detected.

The impact of supplying a mixed culture of lactate producing bacteria on in-vitro rumen fermentation of forage- (Experiment 1) and concentrate- (Experiment 2) based diets in the presence and absence of monensin was explored. In experiment 1, interactions between DFM and MON were absent (P>0.10) for gas production and fermentative end products. Gas production and fermentative end products were unaffected by DFM alone (P>0.10). Monensin decreased (P<0.001) CH4 and NH3 production, rate and total gas production, as well as total VFA concentration and molar proportions of acetate and butyrate. However, MON increased (P<0.001) proportions of propionate, valerate, isobutyrate and isovalerate. Independently, DFM and MON increased (P<0.001) end point pH. In experiment 2, DFM x MON interactions or tendencies (P=0.07, P<0.01, P<0.01) were present, DFM effects were abated by MON, for rate, total gas production and total VFA concentrations. Acetate:propionate ratio was decreased (P<0.01) with MON and was unaffected by DFM. Ammonia-N concentration was increased (P<0.01) by DFM and unaffected (P=0.75) by MON. Both DFM and MON treatment increased (P<0.01) ruminal pH levels. These studies suggest the effects of DFM and MON of in-vitro fermentation are dependent on the substrate being fermented and the observed interactions provide means for further research.

The objective of the first study was to quantify the effects of feeding Schizochytrium sp. microalgae (SP-1, Alltech, Inc., Nicholasville, KY) on milk fat and DHA content. Eight cows were fed: 0, 100, 300, or 600 g of algae per day. Fat percentage was greater (P < 0.05) for cows on treatments 0 g and 100 g than for cows on treatments 300 g and 600 g (P < 0.05). Docosahexaenoic acid in milk was greater for cows on treatment 300 and 600 than for cows on treatment 0 and 100 (P < 0.05). The objective of the second study was to assess yeast supplementation effects on high and low forage dairy cow diets. Four cows were assigned to 1 of 4 treatments: 1) low forage (LF), 2) low forage with 10 g/d yeast (Yea-Sacc®; Alltech Inc., Nicholasville, KY; LFY), 3) high forage (HF), or 4) high forage with 10 g/d yeast (HFY). Only rumination time and DMI were influenced by treatment (P < 0.01). Dry matter intake was 17.05, 13.41, 19.44, and 20.29 ± 1.40 kg/d and rumination time was 442.88, 323.09, 433.34, and 475.50 ± 21.93 min/d for cows on the LF, LFY, HF, and HFY treatments, respectively.

L'acidose ruminale latente (ou acidose sub-clinique) est une préoccupation majeure pour la nutrition des ruminants à haut potentiel de production. Cet état se caractérise par une instabilité du microbiote et des fermentations ruminales qui s'orientent variablement vers le propionate et/ou le butyrate. L'une des stratégies de prévention de l'acidose latente consiste à distribuer dans l'alimentation des ruminants des probiotiques capables de rééquilibrer le microbiote et les fermentations ruminales (dans un sens favorable pour l'animal). L'analyse de la bibliographie montre toutefois que l'effet des probiotiques, et plus particulièrement des bactéries probiotiques (BP), est variable et parfois contradictoire ce qui serait probablement lié à l'instabilité du microbiote. Afin d'étudier la possibilité de prévenir l'acidose latente par les bactéries propioniques et/ou lactiques, nous avons émis l'hypothèse que leur efficacité dépend des orientations fermentaires dans le rumen. Des acidoses latentes butyrique et propionique caractérisées par des profils fermentaires et microbiens distincts ont été développées chez le mouton non productif et la vache laitière pour étudier l'effet et le mode d'action de la bactérie propionique P63 seule ou associée aux lactobacilles Lb. plantarum ou Lb. rhamnosus (P63, Lp + P63 et Lr + P63) sur le fonctionnement de l'écosystème ruminal et les performances animales. Chez le mouton en situation d'acidose propionique, les BP utilisées ont amélioré le pH ruminal via une réduction de la proportion en lactobacilles. Chez la vache laitière, la stabilisation du pH a été associée à une moindre disponibilité en hydrogène susceptible d'être transformé en protons, suite à une augmentation de la propionogenèse et/ou de la densité bactérienne, deux voies consommatrices d'hydrogène. Au cours de l'acidose latente butyrique, l'amélioration du pH n'a été observée que chez les moutons supplémentés avec Lp + P63. Cet effet semblait être dû à une diminution des acides gras volatils et de la proportion en S. bovis mais aussi à un pH initial faible (pH < 5,5) probablement optimal pour l'action des BP ; ce qui n'était pas le cas chez les vaches pour lesquelles le pH initial était compris entre 5,9 et 6,1. En revanche, l'efficacité digestive a été augmentée par l'association de P63 aux lactobacilles chez la vache laitière. L'association Lp + P63 a augmenté les activités fibrolytiques (cellulase, xylanase) et la digestibilité de la matière organique, tandis que Lr + P63 a amélioré la digestion des fibres et a diminué la production de méthane de 25%. Nous n'avons pas observé d'effet sur les performances zootechniques, ce qui serait probablement dû au dispositif expérimental en carré Latin qui n'est peut-être pas optimal pour mettre en évidence l'effet des BP. Nos résultats sont les premiers à démontrer l'efficacité des bactéries probiotiques pour sécuriser et/ou améliorer la digestion des rations et réduire la production de méthane chez le ruminant en acidose, et l'association de P63 avec les souches de Lactobacillus sont les plus efficaces. Enfin, nous avons validé notre hypothèse selon laquelle l'effet et le mode d'action des bactéries probiotiques pour prévenir l'acidose dépendent des orientations fermentaires dans le rumen.

Darbo tikslas buvo įvertinti didžiojo prieskrandžio turinio fermentacinių procesų aktyvumą ir nustatyti pašarų organinės medžiagos (OM) virškinamumą in vitro. Tyrimai atlikti su 9 Lietuvos juodmargių veislės karvėmis tvartiniu laikotarpiu. Didžiojo prieskrandžio turinys buvo paimtas ryklės-stemplės zondu GDZ-1 po rytinio šėrimo. Didžiojo prieskrandžio turinio rodikliai buvo fiziologinės normos ribose: pH buvo vidutiniškai 6,48 ± 0,21, redukcinis bakterijų aktyvumas – 114,2±41,06 s, gliukozės rūgimo reakcijos greitis – 1,69±0,71 cm3/h, LRR 98,33±12,06 mmol/l ir pirmuonių skaičius 226,2±48,63×103/ml. Inkubuojant pašarus su tiriamų karvių didžiojo prieskrandžio turiniu in vitro, nustatėme, kad siloso OM virškinamumas buvo 10,2 ir 36,4 proc. (p<0,001) didesnis nei atitinkamai šieno ir šiaudų. Šieno OM virškinamumas buvo 29,2 proc. didesnis nei šiaudų (p<0,001). / The goal of the study was to evaluate the level of activity of the rumen fermentation processes and determine the digestibility of organic matter (OM) of the feed in vitro. The researches were carried out with 9 Lithuanian Black-and-White cows during the indoor period. The rumen fluid was obtained by using a GDZ–1 pharyngeal and esophageal probe after the morning feeding. The tested physiological parameters of the contents of the rumen were within the normal range: pH was 6.48 ± 0.21 in average, the reduction activity of bacteria was 114.2 ± 41.06 s, the glucose fermentation reaction time was 1.69 ± 0.71 cm3/h, the free fatty acids (FFA) were equal to 98.33 ± 12.06 mmol/l and the number of protozoa was 226.2 ± 48.63 × 103/ml. During the incubation of the feed with the contents of rumen of the studied cows in vitro, we determined that the OM digestibility of silage was 10.2 and 36.4 per cent (p<0.001) which was higher than that of hay and straw. The OM digestibility of hay was higher by 29.2 per cent compared to the straw (p<0.001).

Darbo tikslas: ištirti probiotikų įtaką melžiamų karvių produktyvumui, produkcijos rodikliams ir sveikatingumui. Darbo uždaviniai: 1. Įvertinti probiotiko Probio - active įtaką melžiamų karvių pieno primilžiui ir pieno rodikliams. 2. Įvertinti probiotiko įtaką melžiamų karvių kraujo morfologiniams rodikliams. 3. Įvertinti probiotiko įtaką melžiamų karvių didžiojo prieskrandžio fermentaciniams procesams. Tyrimo metodika: tyrimas buvo atliekamas kooperatinėje bendrovėje „Blauzdžių agroservisas“, 2013 metų birželio – spalio mėnesiais. Bandymo metu buvo suformuotos dvi grupės melžiamų karvių: kontrolinė ir bandomoji, po 115 Lietuvos juodmargių veislės melžiamų 2-5 laktacijos karvių kiekvienoje. Kontrolinėje ir bandomojoje grupėse karvės buvo paskirstytos vienodai, atsižvelgiant į jų laktacijų skaičių ir veršiavimosi laiką. Bandomosios grupės karvės su įprastiniu racionu papildomai gavo probiotiko. Į kiekvienos bandomosios grupės karvių kombinuotuosius pašarus, kiekvieną šėrimo dieną individualiai, buvo įmaišoma po 150 ml probiotiko. Bandymas vyko nuo 60-os iki 120-os karvių laktacijos dienos ir truko 60 dienų. Pirmas 30 dienų bandymas vyko tvartiniu laikotarpiu, o paskutines 30 dienų – ganykliniu laikotarpiu . Bandymo metu buvo naudotas probiotikas Probio - active, įmaišytas į racioną normuojant po 150 ml kiekvienai karvei, normą padalinant į dvi dalis ir sušeriant paros laike per du šėrimus. Tyrimo metu mėginiai pieno tyrimams buvo imami bandymo pradžioje, praėjus 60 d., 90 ir... [toliau žr. visą tekstą] / Aim: to research the effects of probiotics on dairy cows’ productivity, productions values and the overall health. Objectives: 1. To evaluate the effects Probio – active probiotics toward dairy cows’ yield and milk index. 2. To evaluate the effects of probiotics on dairy cows morphological blood indexes. 3. To evaluate the effects of probiotics to the rumens fermentation processes on dairy cows. Methodology of the research: the research was carried out at the cooperative company “Blauzdžių Agroservisas” 2013 June - October. During the research two similar groups of dairy cows were created: the control group and experimental group. The groups were made out of 115 Lithuanian Black and White breed dairy cows in their 2-5 lactation stages each. Cows were considered and maintained under the same conditions. For the experimental group cows with normal diet each day in addition received 150 ml of a probiotic. The study samples of milk were taken for research at the beginning of the test after 60 days, 90 and 120 days, from the start. Haematological tests of dairy cows blood samples were taken at the beginning and the end. The rumen contents - at the beginning and after a two-month test. Results: during the research it was determined that the cows which received probiotics yielded 4.4 percent (p>0.05) more milk opposed to the ones that did not receive probiotics. It was also detriment that the use of probiotics have an effect on the quality indexes (protein, fat), and have... [to full text]

Includes bibliographical references (leaves 226-261). / xxiii, 261 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Investigates nitrogen utilization in some species of rumen bacteria with the object of understanding the role of ammonia versus exogenous amino acids in relation to microbial growth. / Thesis (Ph.D.)--University of Adelaide, Dept. of Animal Science, 1996?

Bibliography: leaves 189-205. / xi, 205 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The aim of this PhD project is to screen feral goat rumen fluid for the presence of new organisms that may play a role in the detoxification of tannins and to investigate their mechanisms of action. An enrichment experiment is conducted to screen rumen fluid for anaerobic bacteria capable of growing in the presence of high levels of "Acacia" condensed tannin. Four morphologically-distinct bacteria are isolated, confirming that resistance is a property shared by more than one organism. One isolate is chosen at random for further characterisation and is identified as a strain of "Selenomonas ruminantium" subspecies "ruminantium". It is arbitrarily designated strain K2. "Selenomonas ruminantium" K2 is shown to be not only tannin-resistant but also able to grow on tannic acid. It is proposed that this bacterium obtained energy for growth from tannic acid. The thesis examines the molecular mechanisms controlling tannin resistance or tannin degradation in rumen microorganisms. / Thesis (Ph.D.)--University of Adelaide, Dept. of Animal Science, 1997

Bibliography: leaves 189-205. / xi, 205 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / The aim of this PhD project is to screen feral goat rumen fluid for the presence of new organisms that may play a role in the detoxification of tannins and to investigate their mechanisms of action. An enrichment experiment is conducted to screen rumen fluid for anaerobic bacteria capable of growing in the presence of high levels of "Acacia" condensed tannin. Four morphologically-distinct bacteria are isolated, confirming that resistance is a property shared by more than one organism. One isolate is chosen at random for further characterisation and is identified as a strain of "Selenomonas ruminantium" subspecies "ruminantium". It is arbitrarily designated strain K2. "Selenomonas ruminantium" K2 is shown to be not only tannin-resistant but also able to grow on tannic acid. It is proposed that this bacterium obtained energy for growth from tannic acid. The thesis examines the molecular mechanisms controlling tannin resistance or tannin degradation in rumen microorganisms. / Thesis (Ph.D.)--University of Adelaide, Dept. of Animal Science, 1997