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The development of the pH-value, the molar quota of volatile fatty acids and of the NH3 content in the change from silage rations to dried rations on the basis of pelleted feed and in dependence on the time after the beginning of feeding was tested in studies of the rumen fluid of four cows in order to explain the causes of the very low NH3 content of the rumen fluid in feeding experiments with rations based on pelleted straw-concentrate mixtures. An influence of the ration type and the time after the beginning of feeding on the molar quota of the individual volatile fatty acids and the NH3 content was ascertained. The ration type tested can cause an NH3 content in the rumen fluid below 1 mmol/l.

In two feeding experiments with 10 dairy cows each the effect of 200 mg monensin Na per animal and day in rations either rich in roughage or in concentrate was studied. In principle, the reactions caused by monensin supplement did not differ between the two types of rations. Monensin supplements resulted in a slight reduction of feed intake, a significantly lower milk fat content and, as a tendency, also a lower milk protein, particularly casein, content and a diminished amount of fat corrected milk (FCM). The pattern of fatty acids in the rumen was shifted in favour of propionic acid and the live weight gain of the cows was higher in the monensin group. There were no improvements with regard to the expenditure of feed and energy per kg FCM.

Unlabelled: Four probes for the acquisition of rumen fluid in adult cattle were tested with regard to their usefulness (pump capacity): probe I = original instrument of Schambye-Sørensen, probe II = modified Schambye-Sørensen instrument, probe III = guidable instrument of Dirksen, probe IV = a simple "home made" plastic instrument with a metal suction head. In a first step bovine saliva was added in increasing quantities (in increments of 5% up to 50%) to normal rumen fluid samples collected via rumen fistula. Some relevant parameters of the rumen fluid were analyzed with these mixtures. The experiments were carried out in order to obtain data for the calculation of saliva inflow in samples collected by orally introduced probes. In a second step a sample of rumen fluid was aspirated from the ventral rumen sac via the fistula before each introduction of the rumen sound. Saliva inflow was calculated on the basis of the in vitro changes in pH and in Na+ and K+ concentrations noted with each 5% addition of saliva., Results: The pH value increased with the addition of saliva more markedly for samples with a lower initial value. The sodium concentration in the rumen fluid increased almost linearly by an average of 2.5 mmol/l, while potassium concentration decreased by approximately 1.4 mmol/l with each 5% increase of saliva. Chloride concentration of the physiologic rumen fluid was essentially unaffected by addition of saliva (up to 30%). The methylene blue reaction was slightly enhanced by admixture of 5 to 10% saliva and prolonged by greater volumes.(ABSTRACT TRUNCATED AT 250 WORDS)

The Cd-determination of 10 different winter grazings for wild ruminants in seven different biotopes showed significant differences of the habitats resulting from the previous Cd-emission of metallurgy smelting non-ferrous metals. The winter grazing of the Tharandt Forest and the Harz mountains contained significantly more Cd than that of the Lower Flaming hills, the western Erzgebirge and the northern agrarian areas. The bark and the tips of conifer twigs, twigs of oak and mountain ash, bilberry and heather plants, i. e. perennial plants resp. parts of plants proved to be particularly rich in Cd. On an average, wild ruminants consume more Cd than domesticated ruminants, which do not consume parts of perennial plants. The rumen contents of all wild ruminants contained, with 0.20 to 0.25 mg/kg dry matter more Cd than could be expected from the content of the grazing. In the Cd-contaminated areas the amount of Cd in the rumen contents too showed the Cd-load. The kidneys, livers and the covering hair of a total of 172 head red deer, roes and mouflons reflected the Cd-load and the dependence of the Cd-level on the age. The Cd-concentration ascertained in the organs of the wild ruminants was compared with that of sheep and cattle. The, on an average, higher Cd-load of the wild ruminants was confirmed. The kidneys of wild ruminants older than five years should, as a general principle, not be eaten and neither should the livers of animals from Cd-contaminated biotopes. The limb defects of mouflons from Cd-contaminated areas are discussed in connection with Cd-induced secondary Cu-deficiency resp. Mn- and Zn-deficiency. A reference is made to further works.

The determination of ribonucleic acid (RNA) in the duodenal digesta and the rumen microbes was carried out colorimetrically with orcinol after extraction with hot NaCl solution, precipitation with phosphotungstic acid and alkaline hydrolysis. 96 +/- 1% of the RNA supplemented to the digesta content was recovered (y +/- s, n = 5). The methodic error (repetition accuracy) was 1.1%. The relation of RNA-N:N (mg/g) in the bacteria mass amounted to 93.8 +/- 3.99 (y +/- s(-y), n = 48) and to 16.1 +/- 0.8 (y +/- s(-y), n = 51) mg RNA/g DM in the duodenal content.

The second installment of information on studies over several years of the energy requirement of young female cattle comprises data of the feed intake, the digestibility and metabolizability of the rations used as well as the nitrogen and energy balances of the test animals in six experiments with varying rearing intensities, in which the N, C and energy balances as well as rumen physiologic values were measured monthly using the respiration test technique. Of four experiments, measured values are available over the whole rearing period from calf to calving. The results received from 680 interpretable test periods are-separated for the six experiments--arranged in aggregate form according to live weight range in order to characterize the development of nutrient and energy metabolization processes at various rearing intensities. The results form an essential basis for the derivation of the energy requirement of young female cattle according to factorial criteria.

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.

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.

The winter grazing of wild ruminants on mantles of slate waste in the Harz mountains and in Gera county were richest in Mn whereas those on mantles of granite waste in the Erzgebirge were poorest. The flora of the shell-limestone, keuper and loess areas contains much less Mn than that of those acid habitats. The Mn-requirement of the wild ruminants grazing in the forests is met however, since bilberry plants (2,080 mg/kg), spruce twigs (984 mg/kg), spruce bark (827 mg/kg), oak twigs (791 mg/kg) and heather (754 mg/kg dry matter) in addition to many other plant species store extremely high amounts of Mn. Solely sallow twigs were poor in Mn (28 mg/kg). Based on 601 samples examined, the Mn supply of wild ruminants is extensively described. The rumen content reflected the plentiful Mn-supply of the wild ruminants living in forests (greater than 400 mg/kg) and the far worse one of field roes, particularly in Mn-deficiency areas for domesticated ruminants (mantle of shell-limestone waste 37 mg Mn/kg dry matter of rumen content). The indicator organs of the Mn-status (liver, covering hair, kidneys) verify the statements made concerning red deer, fallow deer and mouflons, of which a total of 170 head from 14 biotopes were examined. An Mn-deficit of field roes in Mn-deficiency habitats in winter cannot completely be excluded. Mouflons have not yet been able to adapt themselves to the excessive Mn-supply of the acid forest habitats in Central Europe. They stored significantly higher amounts of Mn in liver, covering hair, kidneys, cerebrum and ribs than the other wild ruminants and sheep and cattle. The normal Mn-content of the liver and the cerebrum of red deer, fallow deer and roes corresponds to that of sheep and cattle. Roes and fallow deer have winter covering hair poor in Mn (less than 4.0 mg/kg) in comparison to sheep and cattle.

The following 3 methods of NH3 determination were compared to each other for accuracy, on the basis of their results: microdiffusion acidimetric NH3 analysis, photometric NH3 analysis, using bivalent potassium tetra-iodomercurate, and steam distillation/acidimetric NH3 analysis. The results obtained from steam distillation at pH 7.6 were found to agree with those recorded from microdiffusion. However, photometric NH3 determination, using Nessler reagent, yielded overestimated values due to interference by other rumen juice substances.