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J Bartelt

Publications and source records attributed to J Bartelt.

68 records · Page 4Linked to original sources
PubMed1989

[Nitrogen metabolism in the large intestine of ruminants. 6. Metabolism of intracecally administered 14C and 15N urea in sheep with simultaneous intracecal doses of heat-damaged hay].

Two wethers (28 kg and 33 kg) were supplied with ileocaecal re-entrance cannulae and received a straw pellet ration rich in crude fibre (70.5% straw, 12% chopped sugar beet, 10% cereals, 2% urea, 3% NH4HCO3 and 2.5% of a mineral mixture). In a preliminary period 50% of the digesta flow was collected on 6 successive days for 18 h each. An amount of digesta sufficient for 24 h was apportioned for hourly application and stored at a temperature of -20 degrees C for the main trial. In the main trial the two animals received intracaecally the collected digesta with a supplement of ca. 6 g hay damaged by heat/kg LW(0.75) in hourly portions over 24 h (hay made up ca. 15 and 20% resp. of the DM amount). In addition, each digesta sample was supplemented with 14C and 15N labelled urea (19.7.10(6) Bq 14C urea and 364 mg 15N excess from 15N urea). About 9% of the applied 15N amount was microbially utilized; the utilization quota was thus lower than after the application of partly hydrolyzed straw meal (16% in a previous trial). The 14C activity from 14C urea was quickly eliminated in the form of CO2 in the respiratory gases (at the 18th hour after the end of the infusion 70% excreted as CO2). The half-lives for the urea resulting from the semi-logarithmic decrease of the atom-% 15N excess in the blood plasma were 7.9 and 7.7 resp. 23% and 34% resp. of the applied 15N excess were excreted in urine. The excretion of radioactive carbon in urine, however, was at 2.8% and 4.3% resp. of the applied amount very low 120 h after the beginning of the trial (96 h after the end of the infusion). On the whole one can conclude from this trial that hay damaged by heat has only a low stimulating effect on microbial activity in the large intestine.

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[Influence of reduced water supply on the digestibility of nutrients and on some metabolic parameters in sheep].

A digestibility experiment was carried out under conditions of reduced water supply (1/3 in comparison to the control group) and feed supply ad libitum or on maintenance level with 5 wethers of an average body weight of 43.2 kg. They were fed with alfalfa pellets with a Na supplement in the form of NaH2PO4. The water restriction increases the apparent digestibility of the nutrients (except crude fat), significantly so, however, only in the group fed ad libitum as a result of the lower digestibility in ad libitum feed intake. In the group with water restriction the absolute amount of digested nutrients is diminished, however, and in group Ib (feed supply on maintenance level) falls clearly below maintenance requirements. In a comparison of the values of apparent digestibility of the nutrients acquired by various methods (traditional method and indicator method - HCl insoluble remaining ash) the latter method is more susceptible to error. This method is, however, considerably easier in its execution. In comparison to ad libitum water supply the mean retention time of the feed increases due to restricted water supply. The decreased feed intake seems to have a bigger influence on the mean retention time of the marker than water restriction.

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[The effect of a reduced drinking water dose on the digestibility of nutrients and several metabolic parameters in sheep. 2. N-balance, water balance and several physiologic parameters].

Wethers of an average live weight of 43.2 kg received alfalfa pellets either according to maintenance requirement (1.3 kg = group I) or ad libitum (1.5 times the amount; 2.0 kg = group II). In variant a both groups received water ad libitum, in variant b the animals received 1/3 of the amount of water, which was taken in ad libitum. Apparent digestibility was between 59 and 64%, the lower value of which was ascertained with the higher feed intake in variant a. 85% of the apparently digested nitrogen were excreted in urine after optimal water supply and ca. 100% after reduced water supply, so that a slightly negative N balance (Ib) and an N balance of +2.3% res (IIb) were achieved. The N balances amounted to +9.4% (Ia) and +8.4% (IIa) resp. after sufficient water supply. The water intake in liters/kg consumed DM reached the following values (in brackets total water intake from drinking water + water in the feed): Ia = 3.16 (3.30), Ib = 1.38 (1.52), IIa = 2.94 (3.08) and IIb = 1.58 (1.72). The water balance (in % of the total water intake) reached the following values in the same sequence: 13.7, 13.2, 17.2 and 25.3. The water content of the body (according to the phenazone dilution method determined from one sheep each) decreased in Ib by 4.7% and in IIb by 5.7% and thus did not reach critical limits. The quota of urea N in urine significantly increased after water restriction. Urea concentration and haematocrit in the blood plasma did not show any significant changes in dependence on water intake; the same was ascertained for the molar quotas of volatile fatty acids in the rumen fluid and in faeces.

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PubMedDate not supplied

[Nitrogen metabolism in the large intestine of ruminants. 7. Metabolism of intracecally-infused 15N urea with supplement of starch in bulls].

Three bulls with an average live weight of 228 kg were fitted with ileo-caecal reentrant cannulas for the experiment. The rations were composed of 3 kg maize silage and 3 kg wheat straw pellets per animal and day. In a previous period 50% of the digesta was collected over 12 hours and stored deep-frozen. In the main period the digesta flow was interrupted for 30 hours. The digesta flow was collected quantitatively. In the caecal part of the re-entrant cannula previously collected digesta and starch (over 30 hours) as well as 15N urea (over 24 hours) were supplemented. The amount of starch corresponded to about 10% of the DM of the digesta. Analyses of the urine, faeces, ileum digesta and blood plasma were carried out. The quota of starch clearly stimulates bacterial processing in the large intestine so that 20.5% of the supplemented 15N was excreted in faeces within 24 hours. 91.2% of the 15N in the faeces was localised in the bacteria fraction. Individual differences of the animals distinctly show the connection between the excretion of the 15N in faeces and urine. A decreased isotope excretion in faeces of 17.2% for animal 3 in contrast to the 23% for animals 1 and 2 showed an increased elimination of the 15N through the kidney with 32.7% instead of 25.2%. The largest proportion of the ileum digesta, i.e. 46%, can be localised in the 15N urea fraction; the NH3-fraction is also distinctly labelled. With time progressing, the 15N quota flowing from the rumen to the small intestine increases.

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