The use of a partly-hydrolysed straw meal in the feeding of weaned piglets. 2. Concentration and production of volatile fatty acids in the large intestine by the use of test rations with various portions of straw

The ad libitum influence of various quotas of partly hydrolysed straw meal (PHSM) on the fermentation and production of volatile fatty acids (VFA) in the colon in the measuring periods 2nd and 8th weeks of keeping was checked within a feeding experiment with weaned piglets of the country species (42nd-98th day of life; 1st-8th week of keeping). The straw hydrolysis product was fed in a parallel experiment without or after neutralization with CaCO3 in quotas of, 5, 10 and 15% related to dry matter in comparison to the feeding of sole concentrate feed. The measuring in the 2nd week of keeping (adaptation phase) was blurred by the diarrhea in the groups with regard to the concentration, production and molar proportion of VFA. The concentration and production quota of VFA was diminished and the C2:C3 relation as well as the molar quota of branched-chain fatty acids increased in the comparison of the groups above all under the feeding conditions of the sole use of concentrate and--less distinctly--of quotas of 5% PHSM (insufficient dietetic effect) in the feed mixture. Measuring in the 8th week, in which diarrhea did not play a role in any of the groups, showed a significant, ration specific influence on the fermentation pattern of VFA. With the increasing quota of PHSM in the feed mixture (x) a significantly positive relation with the molar acetate quota (y) could be calculated (y = 52.6 + 0.36x;r = 0.50). The C2:C3 relation after sole concentrate feeding rose to 2.6:1 at a 15% PHSM integration. In this, the molar increase of acetate was predominantly linked with a decrease of the butyrate and valerate quotas. A falling tendency of the molar iso-acid quota in the colon digesta was registered with the growing straw quota in the feed mixture. The daily production quota of VFA varied in the measuring period in the 8th week of keeping between 400 and 800 mmol/animal.d without an ascertainable influence of the crude fibre quota of the straw. In comparative calculations with other test results, however, a significant positive correlation between the daily intake of digestible organic matter and the production of VFA in the large intestine could be proved.     

The feeding of differently treated straw materials to piglets after various weaning times. 2. Fatty acids in the large intestine and parameters of protein, fat, carbohydrate and mineral metabolism in the blood serum during the feeding of untreated, HCl-treated and partly-hydrolysed straw meal

In feeding experiments with piglets of the country species variously treated straw materials were used in concentrate--straw meal mixtures after the traditional weaning date (49th day of life) and studies were made of the fermentation of volatile fatty acids (VFA) in the large intestine (colon) and of the concentration of selected parameters of the protein, fat, carbohydrate and mineral metabolism in the blood serum of the animals. The concentrate--straw mixtures with a 10% straw quota contained untreated (II), HCl treated (HCl treatment without steaming, without (III) and with neutralization, IV) as well as partly hydrolysed straw meal (HCl treatment with subsequent steaming, without (V) and with neutralization with CaCO3, VI) were tested in comparison with sole feeding of concentrate (I) and its combination with wheat bran (VII). With regard to the fermentation processes in the large intestine in a comparison of the feeding groups (I-VII) the highest concentration and production quota of VFA was registered in I and the lowest in II. The straw treatment variants (III, IV, V and VI) took a medium position with regard to this and did not differ from each other. After their application of a significant increase in the molar acetate quota was ascertained in comparison with the sole feeding of concentrate (I), which was also characteristic of the other crude fibre sources (II and VII) and was reflected in the extension of the C2: C3 relation. Only few of the total of 15 selected parameters in the blood serum showed reactions of the intermediary metabolism of the test groups caused by feeding. The decrease of the urea concentration in the serum after the feeding of the treated straw materials (III, IV, V and VI) is particularly remarkable. In general, the urea concentration in the serum was negatively related to growth performance of the test groups. The use of HCl treated straw materials (III-VI) proved to be advantageous in comparison to the sole feeding of concentrate (I) and the use of other crude fibre sources (untreated straw meal (II) and wheat bran, VII) in the feeding regime of the keeping stage 'weaned pigs'.     

Use of partially hydrolyzed and untreated straw meal in the feeding of breeding sows. 3. Nutrient digestibility, feed passage time and mineral balance with the addition of variously treated straw materials compared to concentrate feeding alone

In studies with 16 breeding sows of the country species the feed value of straw materials and their fitness for use were ascertained in a long-term experiment. On the feeding basis of a concentrate ration (IV) untreated (I), HCl treated (II = HCl treatment without steaming) and partly hydrolysed straw meal (III = HCl treatment with subsequent steaming) were tested. In the course of the experiment and at a nutrient level of 1 (maintenance requirement), the digestibility of the organic matter of the ration and that of some major and trace elements, N and mineral balances as well as feed passage rate and water excretion in faeces were ascertained at selected measuring times. The following mean results were achieved: The integration of all straw materials tested lead to a significant reduction of the digestibility of the organic matter of the total ration, the least negative effect was caused by partly hydrolysed straw meal (III). The fractions crude protein, crude fibre and N-free extracts were mainly affected. Straw meal integration had a gravidity-conditioned influence on the daily N balance. Increased N excretion in faeces could only be compensated by non-pregnant animals by a decreased N excretion in urine. The mineral balance (Ca, P, Na, Cu and Mn) remained largely uninfluenced by the straw supplement. The feed passage rate was reduced by the use of all straw meal variants to ca. 50% of the value measured after the sole feeding of concentrate (IV). Feed passage rate and water excretion in faeces were approximately reciprocal. The digestibility of the organic matter of the straw materials ascertained according to the difference method amounted to 7.4 (I), 18.1 (II) and 27.9% (III); that of the N-free extracts in the same sequence to 10.0, 22.0 and 34.9%. The calculated energetic feed value was for I = 70.7, for II = 154.9 and for III = 240.7 EFUpig/kg DM.     

The influence of different straw-based ration type on fermentation and production of volatile fatty acids in the rumen of lactating cows. 3. Rumenal fermentation processes and milk yield criteria after using a low-fiber straw pellet batch as basal ration component and a fully pelleted straw-based ration

Lactating Black-Pied (DSR) cows were used to study, over a period of 100 days, the influence of different basal ration types (I-treated wheat straw pellets, low-fibre; II- monodiet pellets containing 48% of wheat straw; III = conventional rations based on fresh forage and arable root crops) on the molar fermentation pattern and the daily rate of VFA production and some milk yield criteria. Ration types I and II results in almost equal fermentation patterns of the VFA; as against the conventional ration types (III) a significantly higher molar acetate propertion as well as a highly significantly decreased molar proportion of iso-acids were found. The daily rated of VFA production relativated to energy intake were as follows (in the order of the ration types mentioned): 4.9, 4.2 and 5.0, and 3.3, 2.5 and 3.3 moles per 1,000 anergetic feed equivalents (cattle) after 30 and 100 days of feeding, respectively. In both trials, only about 80% of the relative VFA production of the straw pellet-concentrate (I) and conventional (III) ration types were found when feeding fully pelleted diets (II). On account of the relatively wide variation of the experimental results no statistically secured findings were obtained as to the milk yield criteria, but ration type II produced some 200 and 300 kg milk less thant ration types I and III, respectively, during the 100-day experimental period.     

The use of a partly-hydrolysed straw meal for the feeding of weaned piglets. 1. Increased production and feed expense as well as nutrient digestibility and buffer capacity in rations with various high portions of partly-hydrolysed straw meal

In studies with weaned piglets of the land race the usability of partly hydrolysed straw meal (PSM) in concentrate - straw meal mixtures was tested over a period of 56 days (42nd-98th day of life; 1st-8th week of feeding. The hydrolysed straw product was there tested in a parallel experiment each without and after neutralization (by means of CaCO3) in quotas of 5, 10 and 15% as supplement to the concentrate feed (based on dry matter) in comparison to a sole concentrate feeding. Daily weight gain and feed and energy expenditure as well as nutrient digestibility and the buffer effect of the PSM rations were ascertained. Measured by weight gain, feed intake and concentrate- and energy expenditure related weight gain, a 10% quota of partly hydrolysed straw meal in a period near weaning (1st-4th week of feeding) had the highest effect and was far superior to traditional concentrate feeding. Lower quotas of PSM in this period did not show a sufficient dietetic effect (diarrhea symptoms), higher reduced the effect on the performance parameters. In the period more remote from weaning (5th-8th week of feeding) the effect of the straw meal integration was generally reduced, a quota of about 5% proved optimal. The registered higher daily weight gains in the total test period (1st-8th week of feeding in which concentrate - straw meal mixtures (relative 106-130%) were closely related to the daily intake of digestibility organic matter. The decrease in digestibility of organic matter in the total ration remained small with the use of the well fermentable crude fibre from the hydrolysed straw product and the balance was overcompensated by higher feed intake. A pH-value decrease of the feed mixtures and a physiologically suitable influence on the pH-value in the stomachs of the test animals could be ascertained due to the buffer capacity of the hydrolysed straw products used. With regard to this, the non-buffered hydrolysed straw product had a higher effect, which was, among other things, reflected in higher performances.     

The significance of fiber for swine nutrition with special reference to HCl-treated straw meal

The term crude fibre according to the Weend analysis method is insufficient for the nutrition of pigs as it does not comprise pentosanes. During the cooking process they are hydrolysed with diluted acid and do not remain in the crude fibre fraction. As stomach HCl can also hydrolyse pentosane (probably in shorter chains), they are well utilized by the microorganisms in the digestive tract (production of volatile fatty acids). Cereal bran and straw meal contain a particularly high quota of pentosanes in their fibre. The fibre fraction of the plant materials fulfills several functions in the digestive tract: absorption of water at the hydroxyl groups of cellulose and hemicellulose (higher absorption capacity of the digesta and improved passage rate); formation of volatile fatty acids (VFA) by the intestinal bacteria due to the fermentation of pentosanes and cellulose (positive influence of VFA on the mucosa of the intestinal walls); absorption of protein decomposition products (including amines) in the cavities of native plant scaffold substances and absorption of aromatic toxic substances (tyramine, phenol, cresol, tryptamine, indole, skatole, histamine etc.) in the lignin by means of VAN DER WAALS forces and further transport of the toxic substances until they are excreted in faeces. HCl treated straw meal is either a mixture of HCl and straw meal at a ratio of 20 kg half concentrated HCl (17% HCl) and 100 kg straw meal with or without heat treatment (steaming for ca. 30 min). The unsteamed product is called HCl straw meal, the steamed product partly hydrolysed straw meal (PHS). 5-10% HCl--straw meal was successfully used in the rearing of piglets after weaning. In addition to the above-mentioned significance of the scaffold substances for the digestive tract, the HCl improved the pH status in the stomach and the upper region of the small intestine. PHS neutralized with CaCO3 (up to pH 6-7) is suitable for breeding sows, boars, young sows and fattening pigs. PSM contains 25% reducing substances (reducing sugars) in the DM and serves the intestinal bacteria in the production of VFA. In the feeding of breeding sows in the phase of gestation 20-30% of the DM intake could be covered by PSM. The number of viable and rearable piglets was significantly higher than after conventional feeding. HCl--SM and PSM also provide advantages with regard to hygiene. They are not congested by fungi and can well be stored without neutralization.     

The use of partly-hydrolyzed straw meal in the feeding of weaned piglets. 3. The concentration of several parameters of protein, fat, carbohydrate and mineral metabolism in the blood serum during the use of rations with different portions of partly-hydrolyzed straw meal

Rations containing varied quotas of partly hydrolysed straw meal (PHS) were provided in mixtures of concentrate and straw meal, and selected parameters of the protein, fat, carbohydrate and mineral metabolism were registered in the blood serum at intervals (2nd and 8th week of keeping) in studies with weaned piglets of the country species. In a parallel experiment the straw hydrolysis product was provided without or after neutralization (with CaCO3) in quotas of 5, 10 and 15% in the mixed feed in comparison to the sole feeding of concentrate. Only some out of the total of 16 parameters ascertained in the blood serum showed reactions of the intermediary metabolism in the test groups caused by feeding. In general, straw crude fibre integration decreased the cholesterol level in the blood serum. Urea concentration in the blood decreased with the growing quota of PHS in the feed mixture. Deviations from the norm of various metabolites, which were mainly reflected in the period near weaning (2nd week of keeping) in an increased concentration of free glycerol and urea in the blood serum, could predominantly be registered after the sole feeding of concentrate. On the whole, there were thus certain interactions with growth performance, which clearly advocate the use of quotas of 10% of the hydrolysed straw product in the feed mixture.     

The effect of straw in ground and pelleted form on the rumen fermentation and protozoa]

Cows possessing a large ruminal fistula were fed straw meal and pelleted wheat straw to investigate its effect on ruminal fermentation (concentration of NH3 and volatile fatty acids (FFS), pH, molar proportions of FFS, rates of FFS production) and on the protozoa population. The straw-concentrate mixture used in the present trial contained 40% of straw. The feeding of pelleted straw produced a significant rise in FFS concentrations (from 8.8. to 12.3 mMole/100 ml) and a corresponding decline of pH (from 6.7 to 6.1). With high molar proportions of acetate (72 mole%) the influence of the straw diet on molar FFS proportions was low. The NH3 peak observed 1 hr after feeding was higher with the pelleted straw than with the straw meal. The feeding of finely gound straw produced a higher level of FFS production (by 10%) than that of straw pellets. (3.88 and 4.29 mMole per gm DM). The number of protozoa (per ml of ruminal fluid) was 335,000 (straw meal) and 121,833 (pellets). The number of large infusorial cells (Isotricha, Diplodinium, Ophryoscolex) decreased correspondingly from 70,000 (straw meal) to 18,870 per ml (pellets). These results suggest that the feeding of pelleted straw-concentrate mixtures to cows as sole feed will not bring about optimum conditions for ruminal fermentation (FFS formation, protein synthesis) and for the layering of ruminal contents.     

Endogenous nitrogen metabolism in 15N-labeled swine. 3. Endogenous excretion of 15N- and 14C-labeled secretions following a 14C-leucine injection

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.     

Investigation of the feed value of straw

Two groups of four pigs each were fed ad libitum with rations containing 70.7% barley, 7.7% fish meal, 0.7% Sussopan, 0.9% mixed minerals and 20% straw meal. Group 1 received partly hydrolysed straw meal, group 2 untreated straw meal. When those rations were given, weight increase performances of 767 g per animal and day in group 1 and 537 g per animal and day in group 2 were achieved in a preliminary 30-day feeding period. On the basis ofthe weight of the feed remnants, a consumption of 19.7% dry matter of the straw meal (group 1) resp. 18,5% (group 2) of the total intake of dry matter could be ascertained. At an average live weight of 93 kg (group 1) resp. 87.5 kg (group 2) the digestibility of both rations was examined. A significant difference was only found for the crude protein fraction with an apparent digestibility of 74.6% in group 1 and of 79.1% in group 2. Those pigs which received partly hydrolysed straw meal consumed 71.4 g N per animal and day, of which 25,4% were excreted in feces and 32.4% in urine. Those animals which were fed with untreated straw meal consumed 62.9 g N per animals and day of which 20.8% were excreted in feces and 49.7% in urine. The higher N-excretion in feces could also be proved for most amino acids the feeding with partly hydrolysed straw meal. For arginine, serine, glutamic acid, proline, isoleucine and Leucine these differences were significant. Differences concerning N-retention could not be found between the groups. 25% of the organic matter of the partly hydrolysed straw meal, 9.4% of the crude fibre and 44.2% of the N-free extractives were digestible. Of the untreated straw, 12.9% of the organic matter, 5.5% ofthe crude fibres and 21.7% of the N-free extractives were digestible. 193 EFpig were calculated for partly hydrolysed and 105 EFpig for untreated straw meal per kg dry matter. The result of substracting the CaCl2 of the partly hydrolysed straw meal is 205 EFpig per kg dry matter of the straw.     

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

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.     

The merit of using untreated, HCl-treated amd partly-hydrolyzed straw meal in the feeding regime for piglets after early weaning. 3. Parameters of protein, fat, carbohydrates and mineral metabolism in the blood serum of the piglet

In parallel studies with piglets of the country race the applicability of variously treated straw materials was tested in comparison with the conventional feeding of concentrate (I) after an early weaning date (30th-35th day of life) over a feeding period of 8 weeks (1st-8th week of keeping). In the rations containing 10% straw (concentrate-straw mixtures), untreated (II), HCl treated (III:HCl treatment without steaming) and partly hydrolyzed straw meal (IV:HCl treatment with subsequent steaming) were tested. In the 2nd and 8th weeks of keeping blood samples were taken from 4 animals of each group and selected parameters of the protein, fat, carbohydrate and mineral metabolism were subsequently ascertained from the blood serum. About half of the total of the 13 selected parameters showed reactions of the intermediary metabolism of the test groups caused by the feeding. With the parameters on the whole varying in the normal physiologic range, a decrease in the blood urea and creatinine concentration and an increase in the blood glucose level were detected after the use of the concentrate-straw mixtures (III and IV) in comparison with the sole feeding of concentrate (I) and partly also in comparison with untreated straw meal (II), their intensity varying in dependence on feeding and test duration. Particularly towards the end of the experiment, an increase of the activity of alkaline phosphatase was also characteristic, which was in negative correlation with the P content of the serum and in positive correlation with growth performance. The physiologic parameters are discussed in connection with the higher growth performance at reduced concentrate expenditure achieved in III and IV in comparison to I and II.     

The effect of types of rations on a straw basis on fermentation and volatile fatty acid production in the rumen of lactating cows. 2. Ruminal fermentation and milk yield criteria after use of a high-fiber straw pellet batch as a basic ration component

Lactating Black-Pied (DSR) cows were used to study, over a period of 100 days, the influence of different basal ration types (experimental group - straw pellets; control group - dried forage + fodder root crops) on fermentation response and daily production rate of volatile fatty acids (VFA) as well as on some criteria of milk yield. Whilst only slight differences were found between the experimental groups in the molar proportions of VFA, the straw pellet-concentrate ration resulted in a lower VFA production as compared to the conventional ration. The control group's VFA production relativated to energy intake, was found to be of the same level (4.1, 4.3 and 3.9 Mol/1 kilo energetic feed equivalents/cattle) after 30, 60 and 100 days of feeding, respectively. The corresponding values in the experimental group declined from 3.3 to 2.3 and 1.9 Mol/1 kilo EF/cattle when feeding a high-fibre straw-pellet batch as basal ration component. The VFA production rates rather diverging between both groups were not found to have a uniform effect on the milk synthesis processes. Both the daily and the first 100-day milk yields did not differ between the groups but within the range of statistical error. Statistically secured positive correlations were found to exist between concentration and production of VFA which, however, depend on the basal ration type and revealed a relatively wide deviation.     

Use of partly hydrolyzed and untreated straw meal in the feeding of breeding sows. 4. Influence on embryonic mortality and fertility

The influence of a supplement of variously treated straw materials to a ration to dry concentrate (= 1), (untreated = 2, steamed = 3, HCl-treated = 4 and partly hydrolysed = 5) during gestation on fertility and rearing performance, the embryonic survival quota of fertilized ova as well as on some selected metabolites in the blood serum was studied in 3 experiments. The integration of untreated straw meal resulted in significantly diminished performances in comparison to test groups 1 and 5 in all tested parameters of fertility and rearing performance (weight of litter). The best results were achieved in all experiments with rations of concentrate and partly hydrolysed straw meal. The individual test groups the following performance values (number of piglets born alive, weight of litter in kg) were achieved: 1 = 9.3, 12.3; 2 = 6.5, 8.2; 3 = 7.5, 9.6; 4 = 8.6, 12,4; 5 = 10.6, 14.4). Ration specific reactions could only be proved for the parameters glucose and urea out of the metabolites (insulin, glucose, cholesterol, urea tri-iodine thyronine and thyroxine).     

体外产气法评价油菜秆与玉米、豆粕的组合效应

本研究旨在探讨不同比例的油菜秆与玉米、豆粕组合对体外瘤胃发酵及其组合效应的影响。采用体外发酵法研究油菜秆与玉米(0%, 15%, 30%)、豆粕(0%, 15%, 30%)组合的体外发酵参数及其组合效应值的变化,探索优化组合效果。结果表明,随着玉米比例的增加,乙酸、丙酸、丁酸和挥发性脂肪酸生成量相应增加,乙丙比下降。当油菜秆∶玉米∶豆粕为40∶30∶30时,培养液pH,氨态氮(NH₃-N)浓度和乙丙比均极显著下降(P<0.01);48 h产气量、潜在产气量、产气速率、乙酸、丙酸、总挥发性脂肪酸(VFA)浓度和有机物消化率(OMD)均极显著提高(P<0.01)。以48 h产气量、NH₃-N、挥发性脂肪酸浓度和OMD的组合效应值以及综合组合效应值(AEs)为衡量指标,油菜秆∶玉米∶豆粕为55∶30∶15组合的正组合效应最大(P<0.01)。综上所述,在本试验条件下,油菜秆∶玉米∶豆粕为55∶30∶15组合的能氮比例较为合理,瘤胃发酵效率最高,为最优组合,可提高油菜杆的利用效率。     

Studies on nitrogen metabolism in the large intestine of ruminants. 5. Metabolism of intra-cecally infused 15N-urea without and with fermentable material in heifers

Six heifers with a live weight of 215, 227 and 238 kg (experiment 1) and 220, 227 and 233 kg, resp. (experiment 2), were supplied with ileocaecal re-entrance cannulae, jugular venous catheters and bladder catheters. The ration consisted of 4 kg maize silage and 4 kg wheat straw pellets per animal per day. Up to 3.5 kg of the straw pellets, consisting of 73% wheat straw, 10% barley, 12% molasses, NPN salts and a mineral mixture, were consumed per animal per day. In a preliminary period 50% of the digesta flow was collected over 12 h/d on 5 consecutive days and stored in a deep-freeze. During the main trial the re-entrance cannula was disrupted and the flowing digesta were quantitatively collected at the end of the ileum; previously collected digesta were supplemented with 15N urea and every hour over 24 h infused into the caecal part of the re-entrance cannula. Between the 24th and 30th hours the digesta were infused without 15N urea supplement. In trial 2 the digesta were also supplemented with partly hydrolysed straw meal between the 1st and 30th hours (approximately 10% straw meal DM related to digesta DM). There were no differences between trials 1 and 2 with regard to the increase of atom-% 15N excess (15N') in the plasma urea. The 15N labelling decrease of the plasma urea N shows that the half-life is 7.9 h in trial 1 and 7.0 h in trial 2. The NH3 nitrogen in faeces was distinctly higher labelled in trial 2 after the supplement of straw meal than in trial 1. The total N in faeces was also twice as highly labelled as in trial 1. Atom-% 15N' in urine was significantly higher in trial 2 than in trial 1 between the 6th and 16th hours after the beginning of 15N urea supplementation. In the decrease curve of atom-% 15N' (after the 26th hour of trial) the values in trial 1 were generally higher than in trial 2. The higher bacterial protein synthesis in the large intestine in trial 2 (after the supplement of partly hydrolysed straw meal) had the effect that 13.6% of the supplemented 15N' was excreted in faeces by the 30th hour of trial, in contrast to this only 4.7% in group 1. Up to the 4th day after the 15N urea infusion these values increased to 16.2 and 6.1%, resp., only.     

Effects of feeding frequency on intake, ruminal fermentation, and feeding behavior in heifers fed high-concentrate diets

Four ruminally fistulated Holstein heifers (BW = 385 +/- 6.2 kg) were used in a 4 x 4 Latin square experiment to determine the effect of feeding frequency on intake, water consumption, ruminal fermentation, and feeding and animal behavior. The treatments consisted of different feeding frequencies: a) once daily (T1); b) twice daily (T2); c) 3 times daily (T3); and d) 4 times daily (T4). Heifers were offered ad libitum access to concentrate and barley straw. Feeding frequency did not affect DMI (P >0.10), but water consumption tended to increase linearly as feeding frequency increased (P = 0.08). Average ruminal pH was not affected (P >0.10) by feeding frequency, but at 12 h after feeding ruminal pH was greater for T2 than for the other treatments. Total VFA concentration and VFA proportions were not affected (P >0.10) by feeding frequency, except valerate proportion, which increased linearly (P = 0.05) as feeding frequency increased. The concentration of ammonia-N was affected (P <0.05) cubically as feeding frequency increased (greatest for T3 = 9.3 mg of N/100 mL; lowest for T2 = 7.2 mg of N/100 mL). Feeding frequency had no effect on daily percentages of behavioral activities (P >0.05), except for observational behavior, for which there was a linear decrease as feeding frequency increased (P = 0.02). Heifers spent the same time on chewing activities, independent of feeding frequency. However, meal criteria tended to be affected (P = 0.07) by feeding frequency, with T2 (39.4 min) showing the longest intermeal interval. Total daily meal time, meal frequency, and meal size were not affected by feeding frequency (P >0.10), whereas meal length and eating rate showed cubic tendencies (P = 0.10 and P = 0.06, respectively) as feeding frequency increased. These results suggest that in the present experimental conditions, with heifers fed high-concentrate diets and with noncompetitive feeding, a smaller range of ruminal pH values was observed when feed was offered twice daily. Although heifers spent the same time on chewing activities, more stable ruminal conditions were probably achieved by feeding twice daily due to the rumination pattern, which was more constant during daytime in T2 than in T1. Moreover, when daytime and nighttime ruminating activity were analyzed separately, this activity was different in T1 (17.3 vs. 30.8%, respectively; P <0.05) but not in T2 (21.5 vs. 28.0%, respectively; P >0.05).     

The applicable merit of untreated, HCl-treated and partly-hydrolysed straw meal in the feeding regimen of piglets after early weaning. 4. Histological findings in the digestive epithelium of the piglet

In studies with piglets of the country race the applicability of variously treated straw materials was tested in comparison with conventional concentrate feeding (I) after an early weaning date (30th-35th day of life) over an 8-week period (1st-8th week of keeping). In the rations containing 10% straw (straw-concentrate mixtures), untreated (II), HCl treated (III: HCl treatment without steaming) and partly hydrolyzed straw meal (IV: HCl treatment with subsequent steaming) were used in the feeding. Samples were taken of 4 killed animals each in the 2nd and 8th weeks of keeping for the qualitative histologic assessment of palatum durum, oesophagus and stomach, duodenum and caecum, colon ascendens, colon descendens and rectum. Although significantly lower pH values in the stomach were registered after the feeding of feed mixtures III and IV due to increased acidity (pH value decrease by 1.3 to 1.5 units) in comparison to the values in I and II, the lamina epithelialis of the palatum durum remained intact in all groups and without any signs of cauterization. Equally, considerable changes in the comparison of the feeding groups could not be detected in the structures of the oesophagus and the stomach walls or in the qualitative histologic assessment of the duodenum and the caecum. However, there were clearly distinguishable group specifics with regard to the formation of lymphoreticular tissue in the stomach and for the colon ascendens.(ABSTRACT TRUNCATED AT 250 WORDS)     

Endogenous nitrogen metabolism in 15N-labeled swine. 1. Course of 15N-labeling and 15N excretion in urine and feces under 4 different diets

Four male castrated pigs (55-65 kg) either received a wheat--fish meal diet (1 and 2) or a wheat--horse bean diet (3 and 4) without straw meal supplement (1 and 3) or with a supplement of 20% DM partly hydrolysed straw meal to the DM of the ration (2 and 4). In order to investigate whether a 15N-labelling of the pigs is also possible with a protein excess in the ration, the animals 1 and 2 received 24.8 g and the animals 3 and 4 = 11.6 g crude protein/kg0,75 live weight. During a 10-day 15N-labelling 385 mg 15N-excess (15N') per kg0,75 were applied in a mixture of ammonia acetate and ammonia chloride in the feed. During the period of 15N-labelling the following quotas of the applied 15N-amount were incorporated: 1 = 10.2%, 2 = 7.2%, 3 = 18.7%, 4 = 14.4%. 15N-excretion in both TCA fractions of faeces showed a highly significant positive correlation to the increasing content of crude fibre in the 4 diets. The immediate 15N-incorporation into the TCA-precipitable fraction of faeces (from the 2nd of the beginning of the 15N-application onwards) proves that 15N enters the large intestine endogenously (probably as 15N-urea) and serves bacterial protein synthesis. Three days after the last 15N-application the pigs were killed. The following values of atom-% 15N' could be determined in the TCA-precipitable blood plasma and in the TCA-precipitable fraction of the liver: 1 = 0.18 and 0.19 resp., 2 = 0.22 and 0.27 resp., 3 = 0.22 and 0.23 resp. and 4 = 0.24 and 0.26 resp. The other examined organs and tissues showed smaller differences between the test animals. The following atom-% 15N' were measured in the TCA-precipitable fractions on an average of the 4 test pigs: kidney = 0.20, pancreas = 0.18, intestinal wall tissue, duodenum = 0.18, jejunum (beginning) = 0.17, jejunum (end) = 0.15, ileum = 0.15, caecum = 0.16, colon (beginning) = 0.15, colon (middle) = 0.14, colon (end) = 0.13, stomach (cardia) = 0.11, stomach (fundus) = 0.12, spleen = 0.13, heart = 0.12, skin = 0.07 and skeleton muscles = 0.06. The results show that the 15N-labelling of tissues and organs of pigs is also possible at a high level of protein supply by means of an oral application of 15N ammonia salts.     

Effect of a supplement of partly hydrolized straw meal to a diet of fish meal and horse beans on N balance and amino acid excretion in the feces of swine

2 test pigs each (male castrated pigs) of an average live weight of 51-71 kg received either a wheat/fish meal diet (Ia) or a wheat/horse bean diet (IIa). Due to a supplement of partly hydrolysed straw meal the crude fibre content was increased from 3.0% (= Ia) to 10.1% (= Ib) and from 5.2% (= IIa) to 12.1% (= IIb) in the dry matter. This straw meal supplement decreased the apparent digestibility of the crude protein in I from 92.5 to 85.7% and in II from 89.0 to 79.0%. N-excretion in faeces/100 g DM-intake followed the regression line: y = 228 + 31.2x(r = 0.98) y = mg N/100 g DM-intake x = % crude fibre in the DM of the diet The excretion in faeces/100 g DM-intake of 15 investigated amino acids, too, in each case showed a significant increase with the rising crude fibre content of the diet. The widest growth angle (tan alpha) of all the essential amino acids investigated was shown by lysine and those amino acids with branched chains. The conclusion is that in the presence of a fermentable crude fibre source and a good N-supply those 4 amino acids show a suitable bacterial synthesis rate and a low decomposition rate.