Insulin Signaling in Liver and Adipose Tissues in Periparturient Dairy Cows Supplemented with Dietary Nicotinic Acid.

The glucose homeostasis in dairy cattle is very well controlled, in line with the metabolic adaptation during the periparturient period. Former studies showed that nicotinic acid (NA) lowered plasma non-esterified fatty acids (NEFA) concentrations and increased insulin sensitivity in dairy cows. Thus, the purpose of this study was to investigate whether the expression of proteins involved in hepatic and adipose insulin signaling and protein expression of hepatic glucose transporter 2 (GLUT2) were affected by dietary NA and dietary concentrate intake in periparturient dairy cows. Twenty pluriparous German Holstein cows were fed with the same diet from about 21 days before the expected calving date (d-21) to calving. After calving, cows were randomly assigned in 4 groups and fed with diets different in concentrate proportion ("HC" with 60:40% or "LC" with 30:70% concentrate-to-roughage ratio) and supplemented with NA (24 g/day) (NA) or without (CON) until d21. Biopsy samples were taken from the liver, subcutaneous (SCAT) and retroperitoneal (RPAT) adipose tissues at d-21 and d21. Protein expression of insulin signaling molecules (insulin receptor (INSR), phosphatidylinositol-3-kinase (PI3K), protein kinase Cζ (PKCζ)) and hepatic GLUT2 was measured by Western Blotting. The ratio of protein expression at d21/at d-21 was calculated and statistically evaluated for the effects of time and diet. Cows in HC had significantly higher dietary energy intake than cows in LC. In RPAT a decrease in PI3K and PKCζ expression was found in all groups, irrespectively of diet. In the liver, the GLUT2 expression was significantly lower in cows in NA compared with cows in CON. In conclusion, insulin signaling might be decreased in RPAT over time without any effect of diet. NA was able to modulate hepatic GLUT2 expression, but its physiological role is unclear.

Associations between Forkhead Box O1 (FoxO1) Expression and Indicators of Hepatic Glucose Production in Transition Dairy Cows Supplemented with Dietary Nicotinic Acid.

Forkhead box protein O1 (FoxO1) is a transcription factor which promotes hepatic glucose production (HGP) by up-regulating the transcription of gluconeogenic enzymes in monogastric species. The activity of FoxO1 is inhibited by insulin-induced phosphorylation. The aims of the present study were to find associations between FoxO1 expression and variables associated with HGP as affected by feeding regimen in dairy cows during the transition period. Twenty one healthy German Holstein cows were allocated to four groups (LC-CON, HC-CON, LC-NA with 5 cows/group and HC-NA with 6 cows/group, respectively). Cows received 0 (LC-CON and HC-CON) or 24 (LC-NA and HC-NA) g/d nicotinic acid with high (HC) or low (LC) concentrate proportion from -42 days (-41.8 + 4.8; mean + standard deviation) relative to expected calving date (d-42) to d24. Liver biopsy was taken at d-42, 1, 21, and 100. The total protein expression of FoxO1 (tFoxO1) and the extent of phosphorylation of FoxO1 at serine 256 (pFoxO1) were analysed semiquantitatively by Western Blotting. The expression of hepatic mRNA of FoxO1 and seven genes associated with HGP was measured by real-time RT-PCR. Mixed model and Pearson's correlation were used for statistical evaluation with the level of significance at P<0.05. No dietary effect was observed either on feed intake, energy balance, or on the concentration of blood metabolites. Neither time nor diet affected the expression of FoxO1 total protein and mRNA. A NA × concentrate interaction was found in pFoxO1. However, no corresponding dietary effect was found in the mRNA expression of investigated genes. Different patterns of correlations between FoxO1-related variables and investigated indicators for HGP were found at d21 and 100. The results indicated that the regulation of HGP did not take place on the levels of mRNA and protein expression and the phosphorylation of FoxO1 in dairy cows in early lactation.

Haematological and immunological adaptations of non-pregnant, non-lactating dairy cows to a high-energetic diet containing mycotoxins.

Diet change and fatness are supposed to challenge the immune system of the cow. Therefore, immunological and haematological consequences of adaptation to and continued feeding of a high-energy diet were studied in eight non-pregnant, non-lactating Holstein cows over 16 weeks. Blood haptoglobin concentration remained unaltered, suggesting that an acute phase reaction was not induced. Stimulation ability of peripheral blood mononuclear cells and stimulated oxidative burst capacity of granulocytes increased significantly in the course of the experiment after an initial drop. While total leucocyte counts increased, the proportion of granulocytes increased and that of lymphocytes decreased at the same time as the ratio of CD4(+)/CD8(+) lymphocytes did. Capability of rumen microbes to detoxify the immune-modulating mycotoxin deoxynivalenol (DON) was not compromised as indicated by the exclusive presence of de-DON as the detoxified DON metabolite in blood. In conclusion, both diet change and prolonged positive energy balance influenced the bovine immune system.

Effects of an energy-dense diet and nicotinic acid supplementation on production and metabolic variables of primiparous or multiparous cows in periparturient period.

It is well observed that feeding energy-dense diets in dairy cows during the dry period can cause metabolic imbalances after parturition. Especially dairy cows with high body condition score (BCS) and fed an energy-dense diet were prone to develop production diseases due to metabolic disturbances postpartum. An experiment was conducted to determine the effects of an energy-dense diet and nicotinic acid (NA) on production and metabolic variables of primiparous and multiparous cows in late pregnancy and early lactation which were not pre-selected for high BCS. Thirty-six multiparous and 20 primiparous German Holstein cows with equal body conditions were fed with energy-dense (60% concentrate/40% roughage mixture; HC group) or adequate (30% concentrate/70% roughage mixture; LC group) diets prepartum. After parturition, concentrate proportion was dropped to 30% for all HC and LC groups and was increased to 50% within 16 days for LC and within 24 days for HC cows. In addition, half of the cows per group received 24 g NA supplement per day and cow aimed to attenuate the lipid mobilisation postpartum. Feeding energy-dense diets to late-pregnant dairy cows elevated the dry matter (p < 0.001) and energy intake (p < 0.001) as well as the energy balance (p < 0.001) without affecting the BCS (p = 0.265) during this period. However, this did not result in any metabolic deviation postpartum as the effects of prepartum concentrate feeding were not carried over into postpartum period. Multiparous cows responded more profoundly to energy-dense feeding prepartum compared with primiparous cows, and parity-related differences in the transition from late pregnancy to lactation were obvious pre- and postpartum. The supplementation with 24 g NA did not reveal any effect on energy metabolism. This study clearly showed that energy-dense feeding prepartum did not result in metabolic imbalances postpartum in multiparous and primiparous cows not selected for high BCS. A genetic predisposition for an anabolic metabolic status as indicated by high BCS may be crucial for developing production diseases at the onset of lactation.

Changes of Adipose Tissue Morphology and Composition during Late Pregnancy and Early Lactation in Dairy Cows.

Dairy cows mobilize large amounts of body fat during early lactation to overcome negative energy balance which typically arises in this period. As an adaptation process, adipose tissues of cows undergo extensive remodeling during late pregnancy and early lactation. The objective of the present study was to characterize this remodeling to get a better understanding of adaptation processes in adipose tissues, affected by changing metabolic conditions including lipid mobilization and refilling as a function of energy status. This was done by determining adipocyte size in histological sections of subcutaneous and retroperitoneal adipose tissue biopsy samples collected from German Holstein cows at 42 days prepartum, and 1, 21, and 100 days postpartum. Characterization of cell size changes was extended by the analysis of DNA, triacylglycerol, and protein content per gram tissue, and ß-actin protein expression in the same samples. In both adipose tissue depots cell size was becoming smaller during the course of the study, suggesting a decrease in cellular triacylglycerol content. Results of DNA, triacylglycerol, and protein content, and ß-actin protein expression could only partially explain the observed differences in cell size. The retroperitoneal adipose tissue exhibited a greater extent of time-related differences in cell size, DNA, and protein content, suggesting greater dynamics and metabolic flexibility for this abdominal depot compared to the investigated subcutaneous depot.

Description of a bovine model for studying digestive and metabolic effects of a positive energy balance not biased by lactation or gravidity.

Physiological consequences of adaptation to and continued feeding of a high-energetic diet were studied in eight non-pregnant, non-lactating dairy Holstein cows over a period of 16 weeks. The first six weeks served as an adaptation period from the low energetic straw-based diet (3.8 MJ NEL/kg DM) to the high-energetic ration (7.5 MJ NEL/kg DM). Intake of dry matter (DM) increased with dietary energy concentration from 9 to 20 kg/d up to week 9 to 12 and decreased thereafter. The initial live weight (LW) of 550 ± 60 kg was increased linearly and corresponded to an average daily LW gain of 2.3 ± 0.3 kg. Energy balance increased approximately nine-fold to a maximum of 114 MJ NEL/d in week 10. Ruminal fermentation pattern was completely changed from an acetate dominating profile to a propionate based one, which was paralleled by a marked increase in the rumen fluid endotoxin concentration. Unlike blood glucose concentration, which increased continuously, that of cholesterol and triglycerides started to increase after an initial stagnation. In conclusion, both ruminal adaptation to a high-energetic diet and the continued feeding of such a diet induced digestive and metabolic adaptations in non-pregnant, non-lactating cows characterised by a progressing positive energy balance.

[Relevance, measurement and assessment of the antioxidative status in farm animals]. / Die Bedeutung, Erhebung und Bewertung des antioxidativen Status bei landwirtschaftlichen Nutztieren.

Reactive oxygen species (ROS) are generated in living organisms under physiological and pathological conditions. They have to be neutralized by the antioxidative system which consists of enzymatic and non enzymatic antioxidants. Both, the activity of antioxidative enzymes and the capacity of non enzymatic antioxidants are known as the antioxidative status of the organism. If the balance between prooxidative processes and antioxidative system is disturbed oxidative stress occurs. Oxidative stress is considered to be a major risk factor for the reduction of defence mechanisms and development of diseases. The aim of the present work is to describe various aspects of the antioxidative status in several production animal species. Conclusions for management and therapy are drawn when possible. Furthermore the paper provides an overview of methods for assessment of antioxidative metabolism. Farm animals undergo several periods of severe challenge of the antioxidative system during the production cycle. Especially young animals in the first weeks of their life and animals during the periparturient period are at high risk. High yielding live stock generally have to carry a higher oxidative burden in comparison to animals which are on a medium production level or in extensive systems. Other risk factors are unsuitable or spoiled components in the diet and heat stress. Exogenous antioxidant supply can be optimized by feeding fresh roughage or silage of good quality or if necessary by using additives. Changes of the antioxidative system have been described in association with displaced abomasum (DA), abomasal volvulus (AV) and reproductive problems in swine. Pre- and postoperative supplementation of antioxidants has been used with good results as supportive treatment in therapy of cattle with DA.

Differentiation of viable, apoptotic and necrotic cells in bronchoalveolar lavage fluid of normal horses and horses with recurrent airway obstruction.

Proinflammatoric cytokines are released extracellularly during necrosis. These lead to inflammation and destruction of surrounding tissues. The aim of this study was to compare the number of viable, apoptotic and necrotic cells in the bronchoalveolar lavage fluid (BALF) of normal horses and horses with recurrent airway obstruction (RAO) and to determine if fluorescence microscopy is a reliable method for this examination. A group of six normal horses and a group of ten horses with RAO were examined. Samples were assessed using annexin-V and propidium iodide immunofluorescence assay and examined by fluorescence microscopy (16 horses) and flow cytometry (nine of 16 horses). We found no significant differences in percentages of apoptotic and viable cells between both groups. The number of necrotic cells was significantly increased in horses with RAO counted by fluorescence microscopy. Cells with high granularity and macrophages had a significantly higher percentage of necrotic cells than lymphocytes. There was a good agreement between both methods. No significant differences were detected. The correlation between both methods is significant. Higher amounts of necrotic cells in the bronchial lumina of horses with RAO could be a reason for tissue damage and continuous lung tissue inflammation. Fluorescence microscopy was applicable for examination of BALF. Therapy should be aimed at the reduction of necrotic cells in the bronchial lumina. Further studies are required to find ways to reduce inflammatory cell infiltration and necrosis in bronchial lumina.

[Testing for BTV, BVDV and BHV-1 in blood samples of new world camelids kept in middle Germany]. / Untersuchungen von Blutproben im mitteldeutschen Raum gehaltener Neuweltkameliden auf BTV-, BVDV- und BHV-1.

The susceptibility of camelids for infectious agents which may result in severe economic losses or which are strictly regulated for epidemiological reasons in farm animals potentially causes a mutual risk of transmission. This study aimed to investigate the presence of antibodies against bovine herpesvirus 1 (BHV-1), bluetongue virus (BTV) and bovine viral diarrhoea virus (BVDV) as well as the presence of pestivirus antigen in new world camelids in Central Germany. Therefore 107 serum samples from 93 alpacas and lamas from this region which had been obtained from 2007 to 2009 were examined using ELISA, serum neutralisation test, RT-PCR and a pestivirus specific gene probe. All sample were negative for BHV-1 antibodies. Antibodies against BVDV-1 could be detected in four animals, titres reaching from 1:64 to > 1:256. One animal was positive for BTV antibodies in the year 2008. This animal had been tested negative for BTV antibodies in 2007. It can be concluded that up to now, these viruses seem to be of minor importance as pathogens in new world camelids in Central Germany. Therefore the risk of infection originating from new world camelids for production animals could be considered to be rather low in this region at the moment. However, it must be taken into consideration that these animals due to lack of antibodies are fully susceptible in case of occurrence of one of these viruses. For maintenance and improvement of the present status, general hygienic precautions should be applied; direct and indirect contact between animals from different herds must be avoided and virological diagnostic and quarantine should be required trading these animals.

Surgical removal of a dermoid cyst from the bony part of the nasolacrimal duct in a Scottish highland cattle heifer.

The ophthalmologic, radiologic and surgical findings of a 2-year-old Scottish Highland Cattle heifer with a dermoid cyst within the bony part of the nasolacrimal duct and the successful treatment are presented.

Effect of surgical correction of left displaced abomasum by means of omentopexy via right flank laparotomy or two-step laparoscopy-guided abomasopexy on postoperative abomasal emptying rate in lactating dairy cows.

OBJECTIVE: To compare the effects of surgical correction of left displaced abomasum (LDA) by means of omentopexy via right flank laparotomy or 2-step laparoscopy-guided abomasopexy on postoperative abomasal emptying rate in lactating dairy cows. DESIGN: Controlled clinical trial. ANIMALS: 30 lactating dairy cows with an LDA. PROCEDURES: Cows were alternately assigned to 2 groups of 15 cows each to receive surgical correction of LDA by means of 2-step laparoscopy-guided abomasopexy or omentopexy via right flank laparotomy. A 50% D-xylose solution (0.5 g/kg [0.23 g/lb]) was injected into the abomasal lumen during surgery. Jugular venous blood samples for determination of serum D-xylose concentration were periodically obtained after injection. Abomasal emptying rate was evaluated by pharmacokinetic determination of the time to modeled maximal serum D-xylose concentration (T(max-model)). RESULTS: Mean +/- SD abomasal emptying rate was significantly faster after laparoscopy-guided abomasopexy (T(max-model), 192 +/- 51 minutes) than after omentopexy via right flank laparotomy (T(max-model), 264 +/- 94 minutes). Rumen contraction rate and milk yield increased faster after laparoscopy-guided abomasopexy, compared with values obtained after omentopexy; however, milk yield did not differ after the 2 procedures. CONCLUSIONS AND CLINICAL RELEVANCE: Amelioration of abomasal hypomotility after laparoscopy-guided abomasopexy rather than omentopexy via right flank laparotomy may result in faster clinical improvement in the immediate postoperative period in cows undergoing correction of an LDA.

[Investigations on the antioxidative metabolism during the periparturient period in dairy goats with special regard to seasonal differences in feeding and management]. / Untersuchungen zum antioxidativen Stoffwechsel bei Milchziegen im peri- partalen Zeitraum unter Berücksichtigung jahreszeitlich assoziierter Veränderungen in Fütterung und Management.

In a herd of 1400 dairy goats with an average milk yield of 840 kg/year, 40 "Weisse Deutsche Edelziegen" (October-January: n = 19; April-July: n = 21) were examined. Venous blood samples were collected 6-8, 3-4 and < 2 weeks (wks) ante partum (a. p.) and 2-4 days (d), 3-4 and 6-8 wks post partum (p. p.). Antioxidative Capacity of Water soluble substances (ACW) and Trolox Equivalent Antioxidative Capacity (TEAC) were measured in serum; activities of superoxide dismutase (SOD) and glutathione peroxidase (GPX) were measured in an erythrocyte pellet and in whole blood. ACW and TEAC increased significantly 3-4 wks p. p. In summer these two parameters showed significantly higher concentrations than in winter. The SOD had a significantly higher activitiy < 2 wks a. p. and 6-8 wks p. p. GPX-activity showed a constant increase from the beginning of investigations and from 3-4 wks p. p. up to the end of investigations activities were significantly higher than 6-8 wks a. p. The samples ante partum and the first sample taken post partum showed significantly higher activities in summer than in winter. The present study shows, that the metabolic challenge associated to the periparturient period in combination with changing capacity of food intake, influences the antioxidative metabolism in dairy goats. Seasonal depending changes on feeding quality and climate (barn temperature, quality of feeding components) also influence this system.