[Diagnosis of fatty liver in dairy cows]. / Diagnostik der Leberverfettung bei der Milchkuh.

From 27 dairy cows with a mean milk yield of 6900 kg FCM (4% milk fat) per 305 day lactation period liver bioptates 2 weeks post partum (p.p.), milk samples 2, 4 weeks p.p., blood samples 0 (partus), 2, 4 week p.p., measurement of backfat thickness 2 weeks prior to calving, 0, 6, 17 weeks p.p. were taken and body weight and milk yield were determined. Fertility results and disorders appearance were recorded too. Total lipid and triglyceride content were analysed in liver tissue. Acetone concentration was determined in milk and 15 clinical-chemical parameters were elucidated in blood samples. Liver fat concentration shows a great variability from 3.9% to 24%. There is no strong reference value for the distinction between physiological and pathological liver fat concentration. Assessment as to whether increased liver fat levels in dairy cow are indicative of liver damage due to a pathological process should include detection of liver cell damage on the basis of plasma enzymes with closest possible specificity of liver. Glutamate-dehydrogenase (GLDH) is recommended. Liver fat content clearly could be defined exclusively from investigation of liver tissue rather than from analysis of blood or milk parameters. Measurement of backfat thickness provided useful information on the post partum lipolysis rate with a good correlation to liver fat (r to -0.72).

[Experimental studies of the evaluation of the energy balance of dairy cows. 1. Milk production and milk composition]. / Experimentelle Untersuchungen zur Beurteilung der Energie-bilanz der Milchkuh. 1. Mitteilung: Milchleistung und Milchinhaltsstoffe.

Proper assessment of the risk to animal health in early lactation has proved to depend decisively on knowledge of intensity of mobilisation processes as well as of the onset and general pronunciation of subsequent regeneration of endogenic energy reserves. Mere calculation of the difference between estimated energy uptake via feed ration and energy output to sustain milk production would not provide a realistic picture of energy mobilisation and deposition in the organism of a dairy cow. Milk fat levels and quantities but also high milk protein levels and quantities were the milk substances which more clearly than others indicated mobilisation of endogenic fat and protein reserves during the first three weeks of lactation. No information could be derived from milk yield and milk substances as to the onset or level of positive energy balance, following redepositing of energy.

Proliferation of hybridoma cells in low-serum medium.

After stepwise adaptation to PFH-medium with low serum levels over a period of 4 weeks two pools of the IWF-F2 hybridoma have been obtained which can be grown continuously in PFH-medium supplemented with 2 resp. 1% of bovine serum without loss of production of monoclonal antibody. Adaptation of this hybridoma to growth without any serum supplement was not possible during the course of this experimental series.

[Behavior of back fat thickness, the activity of NADP-dependent dehydrogenases from adipose tissue and adipose tissue constituents fat and protein and their evidence for energy metabolism in dairy cows]. / Verhalten der Rückenfettdicke, der Aktivitäten der NADP-abhängigen Dehydrogenasen des Fettgewebes sowie der Fettgewebsbestandteile Fett und Protein und ihre Aussage zum Energiestoffwechsel der Milchkuh.

Studies were conducted into 60 Friesian dairy cattle in the GDR for determination of dorsal fat thickness (DFT), activities of glucose-6-phosphate dehydrogenase (GPDH) and isocitrate dehydrogenase (ICDH) in adipose tissue, concentrations of fat and protein in adipose tissue, 2 weeks ante partum as well as 0, 2, 4, 6, 8, 12, 16, 20, 28, 36 weeks post partum, and liver fat levels, 2 and 4 weeks post partum. DFT, ICDH, GPDH, ICDH-GPDH ratio, fat level, fat-protein quotient, changes in DFT, GPDH, and fat-protein quotient exhibited significant relations with the weeks of lactation. The above 60 experimental cows were subdivided by 6 groups of half-siblings consisting of 10 animals each. Significant differences were found to exist between these groups of half-siblings with regard to DFT, GPDH, ICDH-GPDH ratio, and fat-protein quotient. Within each of the half-sibling groups, significant differences were found to exist between individuals for DFT, ICDH, GPDH, ICDH-GPDH ratio, and fat-protein quotient. The above parameters can be used to describe the energy metabolism of dairy cow via quantitative and temporal curves of fat mobilisation and fat deposition. In the context of both animal health and breeding, more attention should be given to determination of mobilisation and deposition of fat as well as to the post partum energy deficit.

In vitro generated mast cells investigated by monoclonal antibodies.

In the present study we have investigated the development of mast cells under in vitro conditions after depletion of mature mast cells of male Wistar rats by intraperitoneal application of distilled water. The studies were carried out both by monoclonal antibodies (MAb) against rat peritoneal mast cells and by cytochemical techniques. During cultivation the amount of MAb-positive cells increased from less than 5% to 64% after 3 weeks, which was accompanied by increased histamine levels and cell size. After 2 weeks the first Alcian blue stained mast cells were detectable, while safranin-positive granules appeared only after 3 weeks. These findings suggest that there are mast cell precursors in the peritoneum which may differentiate into mature mast cells. The antigen on the cell surface recognized by the MAb seems to be expressed during mast cell maturation.

Investigation of mast cell differentiation in vivo by use of monoclonal antibodies.

In the present study mast cell differentiation/maturation was studied in vivo after depletion of mature mast cells from the peritoneal cavity by injection of distilled water. The reconstituting cell population was characterized by use of different staining methods. Additionally, the monoclonal antibody (MAb) IWF F2, which recognizes a membrane antigen of rat mast cells, was used to follow up mast cell differentiation/maturation in the course of the experiment. The antigen expression was studied both by immunofluorescence of antigen-bearing cells and by MAb inhibition of compound 48/80-stimulated histamine release from mast cells. In the course of the experiment the amount of antigen-positive cells increased continuously from less than 5% to control level (1st and 22nd days, respectively). The expression of the membrane antigen detectable by the MAb precedes the appearance of cytochemically identifiable mast cells for several days. The mast cells mature morphologically and functionally as indicated by increasing size, histamine content and MAb inhibition of compound 48/80-stimulated histamine release. The results obtained suggest the MAb IWF F2 to be a useful methodical tool for additional characterization of mast cell differentiation/maturation processes.

Monoclonal antibodies against rat mast cells differentiate between subtypes.

Four monoclonal mouse anti rat mast cell antibodies were selected which detect an antigenic determinant occurring on connective tissue mast cells of the rat. A strong antigen density was found on peritoneal mast cells whereas pleural and mesenteric mast cells exhibit considerably smaller amounts of the antigen. It does not occur on lung mast cells and basophils, thus permitting a mast cell subtype differentiation according to the expression of a surface antigen. The monoclonal antibodies do not react with IgE or IgE Fc-receptor determinants and do not interfere with the histamine secretion from peritoneal mast cells.

[Nitrogen metabolism in the large intestine of ruminants. 3. Microbial utilization of intracecally administered 14C- and 15N-marked urea in the large intestine of sheep in simultaneous intracecal administration of partially hydrolyzed straw meal]. / Untersuchungen zum Stickstoffumsatz im Dickdarm des Wiederkäuers. 3. Mitteilung. Mikrobielle Verwertung von intrazäkal verabreichtem 14C- und 15N-markiertem Harnstoff im Dickdarm von Schafen bei gleichzeitiger intrazäkaler Gabe von teilhydrolysiertem Strohmehl.

Two experiments were performed on sheep, receiving on maintenance level a pelleted straw ration high in crude fibre (straw, 70.5%; dried sugar beet pulp, 12%; cereals, 10%; urea, 2%; ammonium hydrogen carbonate, 3%; minerals 2,5%). The animals were fitted with ileo-caecal re-entrant cannulas. The effects of the introduction of HC1-partly hydrolysed straw meal into the digesta of the large intestine on the digestion processes in that segment were studied. Under these conditions the metabolism of 14C and 15N labelled urea, which was given into the caecum, was estimated. In experiment 1 (E 1; 2 animals) unlabelled, precollected digesta were hourly reintroduced together with 14C and 15N labelled urea via the caecal cannula. In experiment 2 (E 2; 3 animals) the digesta were supplemented with partly hydrolysed straw meal (10% of the mean daily DM-intake with the ration). The supplement of partly hydrolysed straw meal caused an increase of the 15N excretion with faeces from 13.4% (E 1) to 19.8% (E 2) of the dose. The 15N was mainly incorporated in the bacterial fraction (98% E 1; 96% E 2). As a reason for the increased 15N incorporation into the bacterial fraction of 106.4 mg15N' in E 2 vs. 67.3 mg15N' in the experiment without straw meal supplement the higher supply of energy as fermentable carbohydrates was assumed.

Monoclonal antibodies against rat mast cells.

Four hybridomas have been isolated which secrete monoclonal antibodies against surface determinants of rat peritoneal mast cells. This could be demonstrated by an indirect immunofluorescence assay. The monoclonal antibodies did also react with a portion of mononuclear phagocytes from the peritoneal cavity but not with other lymphatic cells.

[Endogenous nitrogen metabolism in 15N-labeled swine. 3. Endogenous excretion of 15N- and 14C-labeled secretions following a 14C-leucine injection]. / Untersuchungen zu endogenen N-Umsatzprozessen an 15N-markierten Schweinen. 3. Mitteilung. Endogene Ausscheidung von 15N- und 14C-markierten Sekreten nach einer 14C-Leuzininjektion.

Four pigs (59-65 kg live weight) were labelled over a period of 10 days with 15N in the feeding of a fishmeal diet (1), a fishmeal diet + partly hydrolysed straw meal (2), a horse bean diet (3) and a horse bean diet + partly hydrolysed straw meal (4). After a 24-hour fasting the animals were provided with simple cannulae in the upper part of the small intestines. After a fasting period of 24 h all four pigs received a 14C-leucine injection and the cannula secretion was collected in the subsequent 24 h. After the feeding of the diets without straw meal supplement (1 and 3) there were distinct differences in the secretion in comparison with the feeding with straw meal supplements (2 and 4) despite the long fasting period (48-72 h). 14C-activity could already be detected in the TCA-precipitable fraction of the secretion after 3-6 min of the injection in 1 and 3 but only 20 to 25 min after the 14C-leucine injection in 2 and 4. The specific 14C-leucine activity of the TCA-soluble fraction of the secretion was, after the straw meal supplementation to the fish meal diet, 15 times higher 25 min after the 14C-leu-injection, 25 times higher after 70 min, 36 times after 2 h and 1.8 times after 4 h than without straw meal supplementation. For all four diets a specific correlation (r = 0.96) could be ascertained between the increase of 14C-activity/mg N in the TCA-soluble fraction and the increasing crude fibre content in the diet between 25 and 180 min after the injection. Furthermore, a distinctly decreased N-secretion/h could be ascertained (correlation coefficient r = 0.84) with the increasing crude fibre content in the diet. The influence of the crude fibre on the parameters mentioned is seen in the changed osmotic conditions in the secretion, which may be caused by the changed regulation by hormones of the gastro-intestinal tract. The atom-% 15N' in both TCA-fractions of the secretion underwent big rhythmic variations, which is explained by different ratios of the components pancreatic juice, bile, and intestinal juice.

[Studies in fattening bulls on the regulation of phosphorus requirements by ad libitum intake]. / Untersuchungen an Mastbullen zur Regulierung des Phosphorbedarfs durch Ad-libitum-Aufnahme.

Experimental studies into 21 fattening bulls have failed to support the assumption that phosphorus demand might be regulated by ad-libitum intake. A group feeding on lowphosphorus diet was compared to a normally fed control group. Both did not differ from one another regarding consumption of a high-phosphorus mineral mixture. Economically unjustifiable luxurious consumption rather must be expected, depending on taste, habit, and social eating behaviours.

[Variations in the pattern of ruminal volatile free fatty acids, acetoacetate and glucose in the blood plasma of lactating cows after a period of fasting and renewed feeding]. / Veränderungen der flüchtigen Fettsäuren im Pansensaft sowie der freien Fettsäuren, des Azetoazetats und der Glukose im Blutplasma laktierender Kühe nach Hunger und erneuter Nahrungszufuhr

3 lactating cows were fasted for 4 days and then again received food. The trial was performed to investigate the effect of fasting on the concentration and molar proportion of volatile fatty acids in the rumen, on the concentration of free fatty acids and glucose in blood plasma and on the acetoacetate concentration in the blood. Fasting produced a considerable decrease in the total concentration of volatile fatty acids. Processes of ruminal fermentation were characterized, during the fasting period, by a continuous increase in the molar proportions of acetic acid, isobutyric acid and isovaleric acid whereas a significant decline observed to occur in the molar proportions of propionic acid and butyric acid. The reciprocal behaviour of acetate and propionate under conditions of fasting lead to a linear increase in the C2 to C3 ratio from 4.4 : 1 to 9,6 : 1. With renewed food supply all fermentation data returned to normal levels. The concentrations of blood glucose declined after 24 hrs of fasting, remained at the same level for the following 2 days and rose again to normal values on the 4th day of fasting. The concentration of acetoacetate decreased significantly on the first day of fasting to values that were 4 times as high as the initial value. The concentration of free fatty acids in blood plasma increased tremendously to a value 40 times as high as that observed at the beginning of the fasting period. It proved to be a good indicator for the energy requirements of the organism.