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B Piatkowski

Publications and source records attributed to B Piatkowski.

At least 19 recordsLinked to original sources
PubMed1990

Studies on the evaluation of feed protein for ruminants. 1. Passage of nitrogen fractions to the duodenum of dairy cows fed different protein and carbohydrate sources.

The duodenal passages of non-ammonia nitrogen (NAN), amino acid N (AA-N) and microbial N (MN) were measured in seven duodenal fistulated dairy cows (6130 kg FCM/305 d) during lactation receiving 30 different rations similar to those used in dairy practice. The rations consisted of roughage (protein-rich silages, hay) and concentrate mixture (corn, barley, oat) in a ratio of 60:40 on a DM basis or roughage/concentrate mixture/fodder beets in the proportions 60:20:20 or 60:0:40 respectively. N supplements consisted of soya bean meal and peas meal (untreated or treated with formaldehyde in each case), rapeseed meal, fish meal and urea. DM intake varied between 9.6 and 19.1 kg/d, the crude fibre content between 166 and 270 g/kg DM, the crude protein (CP) content between 111 and 184 g/kg DM, the AA content (N basis) of the CP between 51 and 82%, the unfermentable CP content of the CP between 23 and 49% and the organic matter digestibility between 70 and 79%. The duodenal passage of NAN was 24.2 +/- 2.7 g/kg DM intake, 34.9 +/- 4.1 g/kg apparently digestible organic matter (in total tract, DOM), 43.3 +/- 5.5 g/kg apparently digestible carbohydrates or 4.2 +/- 0.5 g/MJ net energy fat, (y +/- s, n = 90). The value measured for AA-N was 16.8 +/- 2.9 g/kg DM intake, and that for RNA-labelled microbial CP was 146 +/- 26 g/kg DOM. NAN passage (g/kg DM intake) correlated more closely with the duodenal digesta flow rate (DFR) (kg digesta/kg DM intake) as an intrinsic animal factor (r = 0.78) and with the rumen content dilution rate (RDR) (passage of microbial-free organic matter at duodenum/kg BW0.75.h) as a ration dependent factor (r = 0.64) than with the UDP fraction (% of ration CP) (r = 0.50) or other ration parameters. It was concluded that the specific effect of protein concentrates in mixed rations on duodenal NAN yields in lactating dairy cows is lower than hitherto assumed. The duodenal NAN yield of a single feedstuff or ration (g/kg DM) in cows is dependent on animal and feeding factors. The DFR could represents a suitable target for breeding activities.

Animal Feed↗
PubMed1990

[The attaching of bypass cannulas to the duodenum of dairy cows].

Described in this paper is a bypass cannula for the small intestine (duodenum, ileum) of dairy cows, with reference being also made to the surgical method used on the duodenum. The bypass cannula is made up to flexible, curved single cannulas, 25 mm in diameter, which by a new design are safely connected to each other in a jointless, non-angular manner. The cannulas are manufactured of Type B 400/40 K PVC paste by means of a casting technique. The connecting link consists of a PVC or piacryl tube, about 45 mm in length, which is pressed by means of sleeve nuts against the collars of the two cannula openings. The bypass cannula weights 160 g and is tightly attached to the body of the animal, so that neither grazing nor calving are obstructed. Bypass problems of the past (leakage from proximal cannula, clogging, accidental opening of cannula connection) have not even occurred to high-performance cows with feed uptake rates between 3.0 and 3.5 kg of dry matter to 100 kg of live weight and corresponding digestion passages up to 400 l daily.

Animals↗
PubMed1989

[The effect of different centrifugation conditions in the isolation of mixed rumen bacteria on their content of nitrogen and diaminopimelic acid: use of duodenal content as raw material].

The objective of the present study was, to investigate the effect of varying conditions of differential centrifugation of duodenal content on the isolation of bacteria (B-fraction) and feed particles + protozoa (FP-fraction). The treatments at low-speed centrifugation were as follows: 100 x g/5 min, 400 x g/10 min, 1000 x g/10 min and 2000 x g/10 min, high speed conditions were 30,000 x g/30 min/4 degrees C. The results of three experiments are given. Analytical examination gave similar results for N-contents for all treatments, the mean values being 7.90 +/- 0.27% (n = 12) for B-fractions and 6.53 +/- 0.73% (n = 12) for FP-fractions. Increasing the low-speed from 100 x g to 2000 x g lead to increasing DAP-contents and decreasing N:DAP-ratios of the bacterial isolates, the values being 2.43, 3.02, 3.22 and 3.39 mg DAP/g DM and 32.0, 27.4, 25.0 and 23.0 N:DAP-ratio. Decreased isolation of bacterial material in the B-fraction in conjunction with increased incorporation in the FP-fraction resulted in rising the speed of the low speed centrifugation. The rates of loss of DAP, measured by comparison with the total amount were 10, 32, 48 and 70% respectively. It was concluded to prefer the isolation of bacteria from rumen fluid.

Amino Acids, Diamino↗
PubMed1988

[The use of ribonucleic acid as a marker for measuring microbial protein yield in the rumen. 1. Chemical determination of ribonucleic acid].

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.

Animals↗
PubMed1988

[The effect of sugar beets in the ration on metabolism in the forestomach of 11 to 20-week-old calves].

The influence of the replacement of cereals by sugar beet in the rations was tested with 6 calves supplied with re-entrant duodenal or ruminal cannulae in 4 measuring periods between their 11th and 17th weeks of life. The control ration (A) consisted of 60% mixed feed, 20% hay and 20% wilted silage, the test ration (B) consisted of 30% mixed feed, 33% sugar beet, 20% hay and 17% wilted silage. A contained 15% crude protein, 32% starch and 2% sugar, B in the same sequence 14, 12 and 24% (amounts in % of DM). The following results were achieved: The functional development of the rumen is largely completed three weeks after weaning. There were no qualitative changes between the 11th and 17th weeks of life. The fermentation of organic matter in the rumen (50...52%) and bacterial protein yield (2.4...2.6 g N per 100 g digestible organic matter) corresponded to that of adult ruminants. The partial replacement of cereals by sugar beet resulted in a significant increase of the molar butyric acid quota to 20.8% (B) in comparison to 13% (A) with the same level of total volatile fatty acids in the rumen, the decrease of the quota of acetic acid to 61.4% (B) in contrast to 73.5% (A) and the reduction of the ruminal NH3 concentration after feeding. The feeding of sugar beets had a positive influence on the passage of starch in the duodenum. The DM-degradation of straw in polyamide bags was also positively influenced. 62.6% (A) and 73.9% (B) of the feed N were degraded in the forestomachs. Per kg DM intake 29.8 g (A) and 28.0 g (B) non-ammonia-N (NAN) were detected at the duodenum. 54% (A) and 64% (B) of NAN consisted of bacteria N. In contrast to adult ruminants at nutrition level 1 (maintenance) a considerable net influx of endogenous N into the rumen was to be observed at a crude protein concentration in the feed of 14 to 15% (in the DM) in both groups. Accordingly, the minimum protein content of the ration (in the DM) should be above 15% in the rearing range studied.

Animal Feed↗
PubMed1987

Ruminal protein degradation and protein value of feeds.

The relationship between dry matter (DM) degradation and crude protein (CP) degradation in the dairy cow's rumen was determined with a view to defining the protein value of feeds for ruminants. The nylon bag technique was applied for these studies. For all the feeds investigate (green fodder and preserves from cocks-foot, ryegrass, alfalfa/grass and meadow grass, as well as alfalfa, extracted soybean meal) a significantly positive relationship was found to exist between the levels of DM and CP degradation (r = 0.73 to 1.0). The regression coefficient b1 (CP degradation as regressor) was found to average 0.87. The positive relationship between DM degradation and CP degradation implies that microbial protein amount and unfermented feed protein at the duodenum are negatively correlated. Model calculations show that, on account of the compensation between microbial protein and feed protein at the duodenum, in feeds with a CP concentration below 200 g/kg DM, the extent of ruminal protein degradation does not exert a marked influence on duodenal protein passage. The partial calculation of the duodenal protein supply on the basis of undegraded feed protein and microbial protein, as practiced in the new models of protein evaluation, leads to systematic errors unless the relationship between DM degradation and CP degradation is considered.

Animal Feed↗
PubMed1986

Effect of the pH value when treating concentrate protein with formaldehyde on protein protection in the rumen.

Nine samples of soybean extracted meal were treated by fumigation in plastic bag with 0.5 g formaldehyde/100 g crude protein, the pH ranging from 2.1 to 10.7. The studies showed that with rising pH (x) the proportion of totally bound (y1, % of formaldehyde amount used) and irreversibly bound (y2) formaldehyde increased (y1 = 77.7 + 1.56x, y2 = 28.2 + 2.04x), whilst the reversible proportion remained constant (45.4% of formaldehyde amount used). The lysine detectable (g/16 g N) after HCl hydrolysis was reduced due to pH raising (y = 101 - 0.67x). Solubility and fermentability of the soybean protein in the rumen were found to rise though. Consequently, the formaldehyde content of the protein was positively correlated with the content of soluble N and fermentable N, respectively, and negatively correlated with the lysine content. These experimental results allow to conclude that the desired protein protection to be attained by treating soybean extracted meal with formaldehyde, is greatly influenced by the respective pH value. To reach maximum protection of the protein against microbial degradation in the rumen (N degradation after 12 hours incubation less than or equal to 20% of total N), the pH value should be below 5. The contents of totally, reversibly or irreversibly bound formaldehyde does not allow any conclusion regarding the protein protection attained. The apparently increased binding rate of formaldehyde is presumably due to the fact that here the reaction stops at the stage of methylol formation (molar proportion 1:1). Under the conditions of acid protein hydrolysis for lysine determination, the released formaldehyde obviously reacts irreversibly with the E-NH2 group of lysine.

Animals↗
PubMed1985

Measurement of the postruminal digestibility of crude protein by the bag technique in cows.

A new method has been developed which permits the crude protein digestibility of feedstuffs in the intestine of cattle to be measured with little effort in terms of samples and experimental work. It consists of welding 0.4 ... 0.8 g of the feedstuff (particle size: 125 ... 1000 micron) into polyamide fabric bags (25 X 40 mm) which are inserted via cannulae into the digestive tracts of fistulated cows from the abomasum/duodenum to the ileum or from the abomasum/duodenum to the faeces. The mean retention time of the bags in the animal was 8.5 +/- 2.7 h from the abomasum to the end of the ileum and (13.3 +/- 1.9 h from the abomasum to the faeces. Up to 15 bags per day and cow may be used. The random error of the method is 1.3% (absolute) when the measurements are performed on two animals using two bags each. Intestinal digestibilities of over 90% were measured for concentrate proteins (except linseed meal) and of 72 ... 95% for forage proteins. Post-ruminal digestion was virtually finished at the end of the small intestine.

Animal Feed↗
PubMed1984

[Transport of urea nitrogen from the intestines into the stomach in dairy cows].

In two experiments with one dairy cow each the utilisation of urea-N after its ruminal or duodenal infusion was comparatively investigated on two crude protein levels and different urease activities in the rumen. The rations contained 9.6 (I) and 14.3 (II) g crude plant protein/100 g dry matter. After completed adaptation 50 g urea were daily infused in the rumen (R, via cannula) in 3 h resp. the duodemun (D, distal cannula of the reentrance cannula) in 6 h with the morning and evening feeding. In experiment II the urease blocker phosphoric acid phenylester diamide (D/PPD) was applied in an additional experiment synchronously with the duodenal urea application. On the first measuring day in each case the urea in the morning feeding was labelled with 17.4 atom-% 15N-excess (15N'). Measuring results in the sequence I R, I D, II R, II D, II D/PPD: 15N'-passage rate at the duodenum within 72 h in the TCA-soluble N-fraction 29, 18, 24, 13 and 16, in the TCA-precipitable N-fraction 59, 25, 41, 11 and 5% of the application, 15N'-excretion within 96 h in milk protein 6.8, 4.2, 4.6, 3.4 and 1.9, in faeces 20, 12, 19, 8 and 4, in urine 20, 32, 34, 56 and 75% of the application, 15N-balance 59, 56, 47, 36 and 21% of the application, passage rate of non-NH3-N in the duodenum 131, 118, 96, 107 and 99% of the total N-intake. After ruminal infusion there always was a higher NH3-concentration in the rumen and 15N-frequencies in the rumen proteins. One can conclude that urea-N that gets into the intestines is to a low degree used for duodenal protein supply as directly utilisable urea-N from the ration in the rumen. The difference increases with the protein content of the ration and the inhibition of rumen urease. The urea N-balance is to a considerably smaller degree influenced by the place of urea infusion particularly at a low level of N-supply, which is due to a better utilisation of the urea-N transported with intermediary metabolism from the intestines. The role of urease as a regulator of urea transport through the rumen wall cannot be corroborated.

Ammonia↗
PubMed1983

[Effect of the content of plant crude protein in the ration on the utilization of urea by the milk cow. 1. Nitrogen digestibility and utilization of urea for bacterial protein synthesis in the rumen].

The utilisation of feed urea in the rumen was tested in 2 experiments with a total of 4 newly lactating dairy cows (13 . . . 15 and 17 . . . 19 kg resp. milk/animal and day) with rumen and duodenal re-entrant cannulae. With the energy supply remaining constant in each case, the rations in experiment A contained 8.7, 12.4 and 14.6 and those of experiment B 10.7, 13,7 and 17.1% crude plant protein in the dry matter. After the supplementation with 120 and 150 g resp. urea/animal and day there were 11.9, 15.7 and 17.8 (A) and 13.8, 16.7 and 20.2 (B) % resp. crude protein in the dry matter. The rations consisted of maize silage and a pelleted mixture of straw and concentrated feed (A) resp. maize silage, alfalfa hay and concentrated feed (B). They contained 10.3 . . . 10.6 (A) and 13.6 (B) kg dry matter with 5.6 . . . 6.0 (A) and 8.2 (B). With the increase of the crude protein level of the ration to 16.7 . . . 17.8, the absolute amount of non-NH3-N (NAN) in the duodenum increased as well. Between N-intake (g/d, x) and NAN-passage corrected by the amount of the endogenous quota (g/d, y) the relation y = 87.3 + 0.55 x (r = 0.80) could be established. NAN-passage (y) as related to N-intake decreased with the N-concentration in the dry matter of the ration (x) according to the equation y = 0.35 + 1.22x-1 (r = 0.57). 70, 62 and 61% (experiment A) and 55, 61 and 51% (experiment B) of the consumed amount of N were apparently absorbed in the intestines as NAN (without endogenous quota). The bacterial N-yield of the rumen (g, y), determined with diamino pimelic acid as microbe marker, was dependent on the consumed digestible organic matter (g, x) as follows: y = 67.3 + 0.021x (r = 0.69). There was no connection with the level of N-supply. The measuring results of the bacterial N-yield show that the utilisation rate of the urea-N decreased rapidly when there was more than 11 . . . 12% crude plant protein in the dry matter of the ration. For the tested ration type (570 . . . 600 EFUcattle/kg dry matter) the urea utilisation potential in the rumen for crude plant protein concentrations of 8.7, 10.7, 12.4, 13.4, 13.7, 14.6 and 17.1% in the dry matter was 13.0, 6.9, 4.1, 2.6, 1.3 and -9.6 g urea/kg dry matter.

Animal Feed↗
PubMed1983

[Protein digestion in ruminant calves].

The influence of various protein sources on N-digestion in forestomachs was investigated with 10 calves of the average age of 12 weeks which were supplied with duodenal re-entrant cannulae. 50 and 100% resp. of the soybean coarse meal-N in the standard ration (A) were replaced by urea-N (B) and lucerne-N (C). The crude protein concentration in the test rations varied between 17 and 19%. In the rumen the average NH3-concentration for rations A, B and C amounted to 7.7, 18.9 and 4.5 mg/100 ml resp., the pH-value was 6.4, 6.8 and 6.3 resp. 2.2, 2.4 and 2.7 g bacteria-N were synthesised per 100 g fermented organic matter. There were significant differences as regards the flow of non-ammonia N measured at the duodenum. Related to N-intake, values of 90, 79 and 104% were registered. 3.7, 3.7 and 4.3 g resp. non-NH3-N per 100 g digested organic matter were found at the duodenum. Under consideration of the high protein level of more than 17% (in the dry matter of the ration) required for this phase of growth, a partial replacement of soybean coarse meal-N by urea-N is of little effectivity. In contrast to this, the complete replacement of soybean protein by lucerne protein could guarantee the protein supply of 12-week-old calves.

Animals↗
PubMed1981

[Isobutylidene diurea as an NPN source for ruminants. 1. Rumen fermentation, digestibility of the nutrients and microbial protein synthesis in dairy cows].

In 3 experiments 2 lactating dairy cows received a mixed ration consisting of 10 kg maize silage, 2.5 kg hay, 2.0 kg barley, 1 kg dried sugar-beet pulp, 1.5 kg maize starch, 0.5 kg sugar, 0.2 kg of a mineral-vitamin mixture and 0.08 kg non-protein nitrogen (NPN) per animal and day. The ration contained 8.3 kg dry matter, 5.1 kEFU cattle and 1.18 kg crude protein, 0.5 kg of which from NPN, and was given in equal shares twice a day. Urea (I) or isobutylidene diurea (IBDU), to which the animals were not adapted (II) resp. adapted (III), were the sources of NPN.IBDU proved to a be a very slow source of NH3 in the rumen. 2 hours after the intake of NPN 48 . . . 75, 5 . . . 9 and 5 . . . 12 mg NH3/100 ml could be detected from I to III. Up to the third hour the concentration of IBDU and urea increased in III, which is due to the slow distribution of the slowly soluble IBDU in the fluid digestaphasis. 12 hours after the feeding the level of IBDU and urea in III still amounted to 25 mg urea/100 ml, in I to 1 mg/100 ml only. In the first 3 hours after supplying the NPN the pH-value of I was more than 1 unit higher than that of II and III. There were no significant differences in the fermentation models between the variants, the concentration of volatile fatty acids was 12.6, 12.3 and 11.1 mmol/100 ml. In the stomachs the digestibility of the organic matter was 52, 51 and 54%, that of the crude cellulose 64, 62 and 66% and that of the starch 91, 93 and 98%. At the duodenum the passage rate of N was 87 . . . 93, 107 . . . 126 and 96 . . . 130% of the N-intake, that of NH3-N 6, 43 and 22 g per day and that of bacteria-N 61 . . . 76, 78 . . . 100 and 76 . . . 96% of the N-intake. 2.3 . . . 2.8, 2.6 . . . 3.2 and 2.1 . . . 3.1 g bacteria-N were formed per 100 g dry matter fermented in the rumen. In the intestines 55 . . . 61, 57 . . . 64 and 48 . . . 71% of the feed-N were available as non-NH3-N. The conclusion is that in comparison to urea and concerning IBDU, the rumeno-hepatic circulation plays a definitely bigger role for the N-supply of the rumen microbes and that the possibility of the better N-utilisation can be derived from that.

Animals↗
PubMed1981

[Isobutylidene urea as NPN source for ruminants. 2. Digestion of 15N-labeled isobutylidene urea in lactating dairy cows].

Two cows with rumen cannulae and duodenal re-entrance cannulae received in the first experiment (Ia and IIa) a conventional diet on the basis of a mixture of maize silage, hay and concentrated feed and after a three-week adaptation to isobutylidene diurea (IBDU)--276 g per animal and day--138 g IBDU with 3.865 mg 15N-excess as a single supplementation to their first meal. In the second experiment (IIa and IIb) after a 6-week break the same cows served a repeated experiment without IBDU adaptation. Irrespective of the adaptation, a re-increase of the 15N-labelling in the TCA-soluble N in the rumen could be proved between the 6th and the 8th hour after the intake of the isotopes, which resulted from the backflow of 15N to the rumen. In the duodenal digesta the maximum labelling of the TCA--soluble N-fraction appeared 12 hours after the intake of the isotopes. At that moment a labelling plateau began in the protein fraction, which lasted to the 36th hour. On an average of all 4 cows approximately 30% of the 15N taken in the TCA-precipitable fraction and 55 and 60% in the TCA-soluble fraction had passed the duodenum up to the 72nd hour after the beginning of the experiment. Up to the 72nd hour after the beginning of the experiment, approximately 15% were excreted in urine, approximately 16% in feces and approximately 7% in the milk. This shows that roughly one half of the 90% 15N-amount measured at its passage in the re-entrance cannula (related to the intake) was metabolised in the rumen at least twice, resp. after the first passage through the duodenum it originated from the intermediary metabolism (e.g. as amino acids and their incorporation as digestion secretions). Negative correlations could be ascertained between the pH-value of the rumen fluid and the 15N incorporation in the rumen proteins as well as 15N-excretion through the TCA-soluble and -precipitable quota of feces. An adaptation to IBDU is obviously not necessary.

Animal Feed↗
PubMed1981

[Effect of crude protein on fertility and urea content of the body fluids of high-yielding cows].

A total of 36 high-yielding cows were -- post partum -- divided into two analogous groups. During the following 90 days they received rations containing 14.5 resp. 19.1% crude protein. The daily milk yield ranged between 27.8 and 28.8 kg resp. 29.4 and 31 kg FCM. The urea content of the milk reached 16.8 and 33.8, that in the blood plasma 19.7 and 38.8 mg/100 ml. The correlation between urea content in milk and blood serum was r = 0.94, between milk and urea content in urine r = 0.69. The period between gravidities of 82 days (14.4%) in contrast to 127 days (19.1%) was distinctly improved, and so was the insemination index (2.0 resp. 2.8). We consider 14.5% crude protein meet the requirement for yields of 30 kg milk, which is approximately 15% below the norm.

Animals↗
PubMed1980

[Studies on the effect of phosphoric phenyl ester diamide as inhibitor of the rumen urease of dairy cows. 1. Influence on urea hydrolysis, ammonia release and fermentation in the rumen].

An amount of 0, 0.1, 0.5 and 1.0% (related to N) of phosphoric phenyl ester diamide (PPD) effective as urease blocking substance was applied to the surface of urea with oilbitumen and fed to cows with rumen cannulae over a period of 31 resp. 164 ... 167 days. (The ration essentially consisted of 4.5 kg dried roughage and 1.5 kg starch or 1.1 kg starch plus 0.4 kg sugar and contained 50 g urea). By treating the urea with PPD, the activity of urease, the hydrolysis rate of urea and the NH3-concentration in the rumen were significantly diminished 0.5 to 2 hours after feeding (alpha = 0.05). The effect of PPD was greatest in the first days and decreased with the advancing feeding period. In the variant with 0.5% PPD the examined parameters were significantly reduced after 142 to 164 days, too. This effect remained traceable in its diminished form even after the preparation was discontinued over a period of 35 days. The dynamics of the NH3-concentration was not altered by PPD after a longer feeding period. One can conclude that PPD inhibits the hydrolysis of urea but does not retard it. In conclusion one can say that, because of PPD, the toxicity of urea is lower without the utilisation of urea being better. Due to PPD the molar propionate level in volatile fatty acids decreases significantly and the acetate-propionate relation is expanded.

Ammonia↗
PubMed1980

[Studies on the effect of phosphoric phenyl ester diamide as inhibitor of the rumen urease of dairy cows. 2. The metabolism of 15N-urea].

Two lactating dairy cows supplied with rumen and duodenal re-entrance cannulae received with their rations containing 8.2% vegetable crude protein 180 g urea per day (I) or urea treated with the urease inhibitor phosphoric phenyl ester diamide (PPD, 1% of the N-quota). The cows, accustomed to urea, received the PPD-urea without adaptation (II) and after a 30-day adaptation (III) to PPD. On the first day of the experiment one half of the urea was given ruminally in its 15N-labelled form. 2 h after the isotope supplementation 62.5 and 24 mg NH3 and 6.58 and 21 mg urea/100 ml could be detected in the rumen juice of I to III. Within 72 h 16.6, 26.1 and 25.2% of the 15N-excess given (15N') passed the duodenum in TCA - soluble form and 31.2, 28.4 and 41.7% in TCA - precipitable form. 15.6, 24.4 and 21.5% of the total amount of 15N were excreted in urine and 4.5, 4.6 and 6.0% in the milk protein. The values for faeces were 14.4, 14,4 and 15.4%. The conclusion from these results and from the dynamics of the relative 15N' in the fractions of the rumen fluid is that with a limited inhibition of rumen urease by PPD as it develops after the adaptation, the utilisation of urea-N can be improved.

Animal Feed↗
PubMed1980

[Studies on the effect of phosphoric phenyl ester diamide as inhibitor of rumen urease in dairy cows. 3. Digestibility of the nutrients and bacterial protein synthesis].

Two lactating cows with duodenal re-entrance cannulae were fed with rations containing 180g urea (A) resp. urea modified with the urase inhibitor phosphoric phenyl ester diamide (PPD, 1 g PPD/100 g N). The cows, accustomed to urea, were not adapted to PPD (B) resp. had been adapted to PPD for 30 days (C). From A to C the digestibility of the organic matter in the stomachs amounted to 52, 47 and 52% and in the total tract to 78, 77 and 79%; the digestibility of crude cellulose amounted to 64, 50 and 62% resp. 69, 64 and 68% and that of starch to 91, 87 and 95% resp. 100% in each case. 71, 66 and 70% of the N were digested. The passage rate of N in the duodenum was 90, 102 and 106% of the N-intake. In the intestines 61, 68 and 76% of the N-intake were absorbed. The passage of bacteria-N in the duodenum was 67, 92 and 71% of the N-intake, that of the sum of NH3- and urea-N 6,8 and 8%. The conclusion is that, with unchanged digestibility of darbydrates, the N-supply of cows should be improved by the modification of urea with PPD after the adaptation of the cows. Cellulose fermentation is inhibited at the beginning of the adaptation to PPD.

Animal Feed↗