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Prebiotics reveal positive effects on the growth performance of pigs and poultry, and might influence intestinal microflora. This, in consequence, could alter recovery rates of digestibility markers. In the current study, we evaluated the suitability of chromium (III) oxide (Cr2O3) and the synthetic alkanes n-dotriacontane (C32) and n-hexatriacontane (C36) as external markers for digestibility estimation compared with the standard total collection method in calves supplemented with galacto-oligosaccharides. Eight male German Holstein calves (average age ± SD = 57 ± 8 days) were divided into 2 milk replacer feeding groups (group receiving galacto-oligosaccharides [A] and control group [B]). Each of 2 groups of 4 individually fed calves received a distinct milk replacer with added markers for 14 days. They were fed twice daily restrictively with milk replacer, concentrate and hay. After an adaptation period of 10 days, total faeces were collected. Faecal marker recoveries (FMR, means ± SD) for C32 were (72 ± 14)% for A and (80 ± 12)% for B. Faecal marker recoveries for C36 was (82 ± 15)% and (88 ± 13)% for groups A and B, respectively. The FMR for Cr2O3 was (102 ± 11)% and (100 ± 1)% for groups A and B, respectively. There were no significant differences between total collection organic matter digestibility and marker based organic matter digestibility when using Cr2O3 and C36. But, when utilizing C32 to calculate nutrient digestibilities, results differed from the total collection method for organic matter, crude protein and ether extract. The results indicate that Cr2O3 and C36 can be applied in digestibility studies with calves and give accurate estimates for OM and nutrient digestibilities without correction for FMR. Keywords: Calves, Marker, Digestibility, Alkanes, Cr2O3, Galacto-oligosaccharides

The basis of a successful assessment of the nutritive value of feeds and an animal's supply with dietary energy and nutrients is having sufficient knowledge on key indicators such as feed intake, diet composition, digestibility and the kinetics of gut passage. In horses and other equids, the determination of such indicators is impractical outside controlled conditions, particularly in pasture-based husbandry. Natural wax components such as n-alkanes, alkenes, primary alcohols and fatty acids might be beneficial estimators, but their application is limited in practice. This review provides a concise view into the application of plant wax components, especially alkanes and their external counterparts, in equine nutrition studies. Recent methodological developments and the current state of knowledge are summarized as an interim conclusion. Methodological limitations still hamper an easy application of the method, and some perspectives for future methodological research are discussed. Conclusively, little information is available on feed plant concentrations and variations of primary alcohols, fatty acids and alkenes, and their natural carbon isotope (13C/12C) ratios. Moreover, the magnitude and the (in)consistency of faecal recovery of these markers is barely described. Methodological research should continue focusing on an effective application of plant markers. In horses, especially plant marker-based methods for the estimation of diet composition and passage kinetics will require much more consideration.

SUMMARYIn horses, the quantity of faeces and the faecal concentrations of plant and synthetic alkanes are inconsistent throughout the day. The estimation of feed intake and digestibility can additionally be limited by irregular and incomplete faecal recovery of alkanes that are used as dietary markers. The correction of alkane concentrations minimizes the bias of estimates, but requires the determination of faeces quantity by total collection. However, in consideration of the dynamics of alkane concentrations in faeces, sampling at selected timeframes throughout a day may be useful in avoiding such correction. Five adult horses were fed a hay-based diet offered three times a day in equal amounts. Horses received a bolus with similar quantities of n-octacosane (C28), n-dotriacontane (C32) and n-hexatriacontane (C36) synthetic alkanes twice a day. Total faeces were quantified over 3 consecutive days. Dry matter intake (DMI), output (DMO) and digestibility (DMD) were determined from the total collection trial and additionally estimated for each of 12 equal timeframes throughout the day. The diurnal patterns of the single faeces quantity (SFQ) and faecal alkane concentrations were similar between horses and were repeated from day to day. The intra-day dynamic of SFQ was pronounced. The dynamic of the faecal concentration was much more pronounced when the alkane was administered twice instead of three times a day. The faecal recovery of alkanes that has been calculated from the total collection trial ranged from 82 ± 4·1% for C36 to 108 ± 11·1% for C28. Measured DMI was 12·0 kg/day, measured DMO was 5·9 kg/day and measured DMD was 0·51. Reliable estimates were obtained for DMI with 12·3 ± 0·79 kg/day for the combination of n-nonacosane (C29) and C28 and 12·1 ± 1·01 kg/day for the combination of n-tritriacontane (C33) and C28 at 2 h after administration, and 12·1 ± 0·96 kg/day for the combination of n-hentriacontane (C31) and C32 at 2 h prior to the morning meal, which included the first bolus administration. When calculated from DMO and DMD, DMI was 12·2 ± 0·89 kg/day for C29 and 12 ± 1·0 kg/day for C33 between 5 and 6 h after the morning meal. Estimates of DMD were unbiased between the 3rd and 4th hour after the morning meal with 0·52 ± 0·014 for C29 and 0·51 ± 0·021 for C33, respectively. The DMO was 5·7 ± 0·34 kg/day and 6·1 ± 0·43 kg/day when estimated 3–4 h after the 2nd meal, or prior to the 2nd bolus administration, using the product of SFQ and the daily defecation frequency or the synthetic alkanes, respectively. Knowledge of defecation dynamics might be helpful for simplifying experimental trials. They specifically followed intake dynamics, which can prospectively be used to select sampling timeframes. Based upon current results, a selection of two to three spot samples of faeces that are evenly distributed between 2 h before and 6 h after the morning meal, which was the time of bolus administration, allows for the greatest reliability. Defecation dynamics are probably less influenced by ration/bolus type, rate of exercise, or gut peristalsis, which nevertheless can result in individual shifts of optimal timeframes.

Synthetic alkanes can be applied as external markers to estimate faecal output, digestibility and passage kinetics and are furthermore easy to combine with plant alkanes for the estimation of feed intake. Successful application requires an accurate and uniform labelling of boluses or feedstuffs, which is in turn supported through simplified handling of the markers during preparation. In this study, it was tested whether melting of synthetic alkanes to wax is able to enhance the accuracy and uniformity of subsequent bolus labelling and further simplifies it. The preparation of alkane waxes was performed on model scale using a portion in a ratio of approximately 1:300 to a dosage, which is recommended for administration in large livestock 2 times a day. Additionally, the temperature sensitivity of a range of synthetic alkanes was studied to clarify so far non-explained losses of alkanes, which were observed frequently during the labelling of boluses and feedstuffs or the processing of samples for analysis. Using n -octacosane (C28), n -dotriacontane (C32) and n -hexatriacontane (C36) synthetic alkanes, three single-component waxes (of C28, C32 and C36, respectively), three binary waxes (C28:C32, C28:C36 and C32:C36) and one tertiary mixed wax (C28:C32:C36) were produced with 30 repetitions each. To assess the impact of melting and re-crystallization, the quantity of individual alkanes was determined by gas chromatographic analysis (GCA) in untreated crystals, crystalline mixtures (GCA1) and the finished model waxes (GCA2). Additionally, sub-samples of the waxes were heated for 30 min at 100 °C or freeze-dried for 48 h, respectively, to simulate baking of boluses or freeze-drying as an alternative method for preparation (GCA3). The temperature sensitivity of n -tetracosane (C24) to n -octatriacontane (C38) even-chain alkanes was studied by thermogravimetric analysis (TGA) with consistently increasing temperature (20 to maximal 600 °C at 10 K/min, TGA1) and under isothermal conditions (180 °C for 20 min, TGA2), respectively. Depending on chain length and thus molecular weight of alkanes, weight reduction by emergence of soot during heating-up started between 176 °C (C24) and 227 °C (C38) and further increased rapidly. Throughout isothermal treatment, weight loss from alkanes was lowest with highest chain length (0.0% for C38) and vice versa (23.8% for C24). The originally weighed and via GCA measured quantities of crystalline alkanes did not differ ( P >0.05), except for single C36, where the measured quantities were always higher than the weighed ones ( P =0.019). The weighed and measured quantities of individual alkanes in single-component and of total alkanes in multi-component waxes were similar with a maximal relative difference of 6.6±5.5%, given as the mean ± standard deviation among the repetitions of a sample variant. The relative difference between weighed and measured quantities of individual alkanes in multi-component waxes was maximal 47.4±25.7% and was highly variable. Unexpectedly, the relative difference between weighed and measured quantities was low for C28 (5.9±5.8%) and C32 (5.7±4.3%) in their combined binary waxes. The additional treatment (baking or freeze-drying) did not alter the recovery of alkanes from the model waxes. Synthetic alkanes are thermolabile why exposure to high temperature during preparation of boluses or labelling of feedstuffs needs to be assessed critically. Reasons for that might be complex disorders of the conformation of alkane molecules particularly during the melting of alkane mixtures and the apparently incomplete separation following re-crystallization from the melt. This may lead to displacements within waxes, which cannot be foreseen or quantified, and thus to the loss of their suitability as dietary markers. Alkane recovery from binary waxes of C28 and C32 was unbiased on model scale and whether this can be confirmed on original scale needs to be validated further. For practical use, alkane waxes might nevertheless be beneficial because the handling is easier than that of alkane crystals.

External markers are useful or required to estimate forage intake, digestibility, faecal output and passage rate in horses. Oral administration is challenging because of horses’ high sensitivity and selection skills. A suitable bolus matrix should ensure high and consistent acceptance. Boluses were investigated with and without labelling. Synthetic alkane wax, embedded in filter paper or contained in hypromellose capsules, was used as a test marker. Boluses were baked (100 °C, 30 min) or freeze-dried. The freeze-dried boluses varied in size (1.5, 2, or 3 cm O ) and drying time (6, 12, 24, or 48 h). In two tests (AT1 and AT2), acceptance by the horses was assessed with scores between 1 (complete intake) and 4 (refusal). In AT1, marginal rejection of the marker was recorded, whereas the following tests were performed with placebos only. In two bending tests (BT1 and BT2), the force required to break the boluses (FL, flexural load) was determined because this may affect acceptance. Pre-selected variants were stored for 4 weeks in closed boxes under controlled conditions (20 °C and light for 16 h/d, 16 °C and night for 8 h/d, and 65% relative humidity) and were subsequently analysed for residual moisture (RM) and spoilage-indicating microbes. In baked boluses, the alkanes were partly found outside of the inner matrices. This was not evident in the freeze-dried variants. Acceptance of the labelled boluses (scores≤1.7±0.18, AT1), baked placebos (scores≤2.2±0.35, AT1) and the freeze-dried placebos (scores≤1.1±0.31, AT2) was consistently high. This was explained by the BT, with a mean FL of 202±16.5 N for the baked (BT1) and up to 257±22.5 N for the freeze-dried placebos (BT2) being obtained, which was close to the masticatory forces in horses. However, when the boluses distinctly exceeded a size of 3 cm O , this size probably led to increased FL (BT1), thereby depressing the acceptance of the dried placebos (AT1). The results indicated that the adaption to suitable boluses can lead to increased acceptance. Limiting the drying time to at most 24 h seemed justified, especially for the smaller boluses. After 6 and 12 h, the RM was 7.5±0.52% (1.5 cm O ) and 5.7±0.52% (2 cm O ), which make the risk of microbial spoilage appear low. Tested boluses were unspoiled for up to 1 month after preparation. It was suggested that the variable sizes of the boluses may enable the use of various marker dosages and, incidentally, also use in different target animals. A freeze-dried matrix is likewise open to use with other thermolabile markers or substances. We recommend the pre-administration of placebos prior to marker administration to ensure high acceptance of the labelled boluses.

In pasture-based dairy production systems, dairy cows often receive a silage- and concentrate-based ration [total mixed ration (TMR)] during wintertime and are gradually introduced to fresh herbage in spring. The present study aimed to investigate how the transition to this new nutritional situation influenced different production and health indicators. A 10-wk trial was performed in spring 2014, including 60 dairy cows of the German Holstein breed (166 ± 23 d in milk, 23.5 ± 3.7 kg of milk/d; means ± SD). The cows were divided into a pasture and a confinement group (PG and CG, respectively). The CG stayed on a TMR-based diet (35% corn silage, 35% grass silage, 30% concentrate; DM basis), whereas the PG was gradually transitioned from a TMR- to a pasture-based ration (wk 1 = TMR-only, wk 2 = 3 h/d on pasture, wk 3 and 4 = 12 h/d on pasture, wk 5–10 = pasture-only). A continuous grazing system was implemented on a ryegrass dominated pasture and temperature humidity indices were assessed based on continuous recording of temperature and humidity indoors as well as outdoors. Dry matter intake (DMI) from TMR, milk production, body weight (BW), and body condition score decreased as soon as the PG had partial access to pasture. Milk production and BW decreased even further in the first week on a full grazing ration, but thereafter BW increased again and milk production stabilized. The DMI estimation using the n-alkane method in wk 7 and 9 revealed an increase in DMI from pasture between the 2 time points and indicates an adaptation of grazing behavior and metabolism over several weeks. Increased serum β-hydroxybutyrate and fatty acids concentrations at several time points, as well as a continuous body condition score decrease during the whole course of the trial, indicate an energy deficit in the PG. A significant correlation between serum glucose concentrations and the temperature humidity indices was observed. An increase in serum and milk urea concentrations as well as an increase in the urine total N to creatinine ratio occurred in the PG. To assess possible negative effects of the ration change on metabolic and liver health, different clinical chemistry variables and complete blood counts were assessed. No biologically relevant changes were observed for serum albumin, total protein, cholesterol, aspartate transaminase, γ-glutamyltransferase, and glutamate dehydrogenase concentrations, as well as for white and red blood cell counts.

Since 2013 the efficacy of new live Salmonella Enteritidis (SE) vaccines for chickens needs to be demonstrated according to European Pharmacopoeia Monograph 04/2013:2520 to receive approval in the EU. The purpose of this study was to determine whether a vaccine licensed since 1999 could also fulfil the required tests of the current guideline. For this, Salmonella-free chickens (n = 50) were vaccinated on their 2nd, 46th and 84th day of life with the live attenuated S. Enteritidis strain IDT No. 441/014. Non-vaccinated control animals (n = 50) were kept accordingly. To demonstrate the duration of immunity 20 animals of each group were challenge infected 65 weeks after the last vaccination with a virulent SE (PT 4) strain. According to the monograph, cloacal swabs were taken 3, 5, 7, 10 and 14 days post challenge (dpc). Tissue samples of liver, spleen, caeca, ovaries and oviduct were collected during necropsy of 10 animals per group on 7 and 14 dpc, respectively. All samples were analysed bacteriologically regarding the presence of the challenge strain. The number of challenge strain positive tissue samples and cloacal swabs was significantly reduced in vaccinated animals (p < 0.05). Therefore, the vaccine strain complied with the EP guideline. This study is the first that demonstrates the efficacy of this vaccine according to the current regulations. However, efficacy could also be shown during the development of the vaccine but by use of another animal model that comprised fewer animals per group. The use of this model is no longer accepted by EU regulatory authorities. The results need discussion in context with the 3R principle.

Near-infrared spectroscopy has been successfully used in predicting nutrient digestibility and other parameters, e.g. diet composition from the spectra of faeces samples in herbivores (FNIRS). The objective of the present study was to investigate if the chemical composition of diets and faeces, as well as the apparent digestibility of organic matter (OM), crude protein (CP), neutral-detergent and acid-detergent fibre (aNDFom, ADFom) and crude fibre (CF) can be predicted with sufficient accuracy from spectra of pigs’ faeces. Faecal samples (n = 202), together with detailed information about the chemical composition of these samples and the diets supplied, were provided from five very different digestibility trials with growing pigs. Faecal spectra were obtained by NIRS and calibrations were developed using the complete dataset. Accuracy of calibration equations was assessed by means of standard error of cross-validation (SECV) and the RPD value (standard deviation of lab results/SECV). The prediction of the chemical composition of the diet was considered successful, as all calibration equations had RPD values well above 2, the value that indicates sufficient accuracy. The chemical composition of faeces was predicted with good to sufficient accuracy. Calibrations developed to estimate the apparent nutrient digestibility from faecal spectra worked well for OM and CP, with a SECV of 0.024 for both and RPD values of 2.1 and 2.4. This very promising result merits further investigation. The prediction of the apparent digestibility of fibre fractions was less successful. We conclude that the FNIRS approach is feasible for use in pig nutrition research for predicting the chemical composition of diet and faeces, as well as to determine the apparent digestibility of OM and CP in situations where controlled digestibility trials are not possible.

In this paper count data with excess zeros and repeated observations per subject are evaluated. If the number of values observed for the zero event in the trial substantially exceeds the expected number (derived from the Poisson or from the negative binomial distribution), then there is an excess of zeros. Hurdle and zero-inflated models with random effects are available in order to evaluate this type of data. In this paper both model approaches are presented and are used for the evaluation of the number of visits to the feeder per cow per hour. Finally, for the analysis of the target trait a hurdle model with random effects based on a negative binomial distribution was used. This analysis was derived from a detailed comparison of models and was needed because of a simpler computer implementation. For improved interpretation of the results, the levels of the explanatory factors (for example, the classes of lactation) were not averaged in the link scale, but rather in the response scale. The deciding explanatory variables for the pattern of visiting activities in the 24-hour cycle are the milking and cleaning times at hours 4, 7, 12 and 20. The highly significant differences in the visiting frequencies of cows of the first lactation and those of higher lactations were explained by competition for access to the feeder and thus to the feed.

1. The objectives were to study the variation in amino acid (AA) digestibility of rapeseed meal in laying hens and to investigate whether the variation in AA digestibility can be explained by chemical constituents of the rapeseed meal. Nine rapeseed meals from different processing plants operating in Germany were used. The crude protein and crude fibre concentrations of the meals ranged from 367 to 410 and 137 to 175 g/kg dry matter (DM), respectively. The concentrations of total glucosinolates varied between 5.1 and 12.9 mmol/kg DM. Each meal was included in one of the experimental diets at an inclusion level of 200 g/kg at the expense of maize starch. 2. A total of 16 Lohmann Brown laying hens were used for this experiment and were surgically caecectomised. They were housed individually in metabolism cages. Each of the 10 diets was fed to at least 6 hens in 4 periods of two weeks duration. Excreta were collected during the last 5 d of each period. The digestibility coefficient of AA was calculated for each diet. The digestibility of the rapeseed meals was calculated by multiple linear regression analysis. 3. Mean essential AA digestibility of rapeseed meals varied between 0.78 and 0.84. Among the essential amino acids, the ighest level of digestibility was found for arginine (0.88) and methionine (0.87), and the lowest for lysine (0.74) and threonine (0.75). The highest variation between rapeseed meals in digestibility was found for threonine (0.68 to 0.79) and lysine (0.68 to 0.78). The concentration of neutral detergent insoluble nitrogen of the rapeseed meals was negatively correlated with the digestibility of lysine, but was not significantly correlated with digestibility of any other AA. Glucosinolate concentration was significantly correlated with valine digestibility. 4. Multiple regression analysis showed that the concentrations of crude protein and ash together were the major factors considered to explain variation in digestibility of essential AA. Additional consideration of neutral detergent insoluble nitrogen and total glucosinolates improved the goodness of fit only marginally and was unlikely to be of practical significance.

Beet pulp contains high amounts of pectins that can reduce the risk of rumen disorders compared to using feedstuffs high in starch. The objective was to study the effects of inclusion of ensiled pressed beet pulp in total mixed rations (TMR) for high-yielding dairy cows. Two TMR containing no or about 20% (on dry matter (DM) basis) beet pulp silage were used. The beet pulp silage mainly replaced maize silage and corn cob silage. The TMR were intentionally equal in the concentrations of energy and utilisable crude protein (CP) at the duodenum. TMR were fed to 39 and 40 dairy cows, respectively, for 118 days. The average daily milk yield was about 43 kg/day. No significant differences in milk yield and milk fat or milk protein content were detected. DM intake of cows was significantly reduced by the inclusion of beet pulp silage (23.0 v. 24.5 kg/day). However, a digestibility study, separately conducted with sheep, showed a significantly higher organic matter digestibility and metabolisable energy concentration for the TMR that contained beet pulp silage. In vitro gas production kinetics indicated that the intensity of fermentation was lower in the TMR that contained beet pulp silage. In vitro production of short-chain fatty acids, studied using a Rusitec, did not differ between the TMR. However, the inclusion of beet pulp silage in the ration caused a significant reduction in the efficiency of microbial CP synthesis in vitro. The amino acid profile of microbial protein remained unchanged. It was concluded that beet pulp silage has specific effects on ruminal fermentation that may depress feed intake of cows but improve digestibility. An inclusion of beet pulp silage of up to 20% of DM in rations for high-yielding dairy cows is possible without significant effects on milk yield and milk protein or milk fat.

BACKGROUND:Moringa stenopetala is a multipurpose tree which has several agricultural, industrial and medicinal uses. The nutritive value of East African M. stenopetala has not been fully investigated and pertinent data for ruminants are lacking. The present study was therefore conducted to fill this gap by providing the latest information on chemical composition and in vitro fermentation of M. stenopetala tree parts. RESULTS: The respective metabolizable energy values for leaves, seeds and seedpods were 10.0, 7.0 and 5.1 g kg−1 dry matter (DM). The crude protein (CP) contents for leaves, seeds and seedpods were 395, 282 and 110 g kg−1 DM, respectively. For leaves and seeds, 88% and 83%, respectively, of the CP was true protein. Fat contents (g kg−1 DM) were relatively high in seeds (334) but not in leaves (84) or seedpods (110). No starch was detected in seeds. Leaves were a potentially useful source of calcium,, sodium and manganese, containing 18.5, 4.1 and 0.086 g kg−1 DM, respectively. The concentrations of essential amino acids in leaves for leucine, valine, phenylalanine, isoleucine and threonine were 8.5, 5.3, 5.3, 4.5, and 4.4 g 16 g N−1, respectively, and were comparable to those found in soybean and Moringa olifera leaves. The contents of total phenols in seeds and leaves were 1.2 and 56.7 g kg−1 DM, respectively. CONCLUSION: The chemical composition of leaves and seeds from M. stenopetala revealed its potential as a protein and energy supplement for ruminant livestock. Copyright © 2008 Society of Chemical Industry

An experiment was conducted with eight adult wethers housed individually in metabolism crates to determine the suitability of alkanes to serve as passage rate markers in sheep. Two diets consisting of lucerne (800 g DM/d), without (treatment ‘Lucerne’) and with coarse maize meal (270 g DM/d; treatment ‘Lucerne–Maize’) were fed to four sheep per diet twice daily in equal proportions. Lucerne fibre was prepared from chopped lucerne silage and mordanted with chromium during 24 h cooking with sodium–lauryl–sulfate (Chromium–mordanted lucerne fibre: LF- Cr ). The synthetic alkane C36 was dissolved in heptane and sprayed onto lucerne fibre which had been similarly prepared (LF- C36 ). C28 was dissolved in heptane and sprayed onto maize meal (M- C28 ). Markers were fed at the same time as a pulse dose. For a period of 10 days, rectal grab faeces samples were taken in intervals of increasing length (2–12 h). A multi-compartment-model was fitted to the marker excretion curves. Maximum marker excretion appeared earlier for alkane markers than for Cr in both treatments. Within treatment Lucerne no significant differences between Cr and C36 were detected for Rumen mean retention time (MRT) ( P > 0.05). Numerical differences were observed for RumenMRT in treatment Lucerne–Maize between LF- Cr and LF- C36 and M- C28 (33, 25 and 25 h), respectively. Further numerical differences were observed in CaecumMRT for LF- Cr and LF- C36 in treatment Lucerne and for all markers in Lucerne–Maize. In treatment Lucerne, faecal recoveries of markers LF- Cr and LF- C36 were 95 and 85%, in treatment Lucerne–Maize 101 and 88%, and for M- C28 in the treatment Lucerne-Maize only 75%. It was shown that the lower faecal recovery of alkanes by itself does not cause biased estimates of passage rate parameters. However, further investigations are necessary to determine the relationship between the time a particle has spent in the digestive tract and the disappearance of the alkane marker, as this could introduce a bias to the estimate. The major shortcoming of alkanes as passage rate markers seemed to be migration between solid and liquid phases of the digesta. This problem could be overcome by new labelling procedures or the use of 13 C-labelled native alkanes.

Summary Studies on the use of lucerne silage as a forage source for high-yielding dairy cows It was the main objective of this study to investigate effects of lucerne silage inclusion in maize silage-based rations on dry matter intake, milk yield and metabolic parameters of high yielding dairy cows. Three total mixed rations (TMR) were used. They contained as the main forage source on a dry matter basis 41.5% maize silage and 12% grass silage (ration maize) or 18% maize silage and 29% of either grass silage (ration grass) or lucerne silage (ration lucerne). Organic matter digestibility, determined with wether sheep, was 77 and 65% for the grass and the lucerne silage, respectively. Each TMR was fed to 4 wether sheep to determine crude nutrient digestibilities. The content of net energy for lactation (NEL), as calculated from digestible crude nutrients, was (MJ/kg dry matter (DM)): 7.1 (maize), 7.2 (grass) and 6.8 (lucerne). Based on the results of a chemical fractionation of crude protein it was calculated that the content of utilisable crude protein (nXP) was not below 167 g/kg DM and that the N balance in the rumen was not negative for all 3 TMR. The TMR were fed for 169 days to at least 28 dairy cows per treatment which were in their first half of lactation. Feed intake, milk performance data and physiological indicators were measured for each individual cow. The DM intake was significantly higher in treatment lucerne (23.2 kg/d) than in treatments grass (21.2 kg/d) and maize (22.6 kg/d). Daily intakes of NEL and nXP were significantly lower in treatment grass than in the other two treatments. Milk yield was significantly higher in treatment maize (41.7 kg/d) than in treatments grass (37.3 kg/d) and lucerne (38.5 kg/d). This was associated with a significantly lower milk fat content in treatment maize (3.5%) in comparison with the other two treatments (3.9% each). Milk protein content was unaffected by treatment (3.4% on average). Similarly, the acetone content of milk was not significantly different between treatments. The β-hydroxybutyrate content of the deproteinized blood was significantly higher in treatment lucerne at start of lactation, but this difference disappeared in subsequent parts of the experimental period. Measurements of back fat thickness indicated mobilisation and retention of energy by cows during the experimental period to be similar in all treatments. It is concluded that lucerne silage is a suitable forage source for high yielding dairy cows in spite of its low digestibility. Zusammenfassung In dieser Untersuchung sollte geklart werden, wie sich ein Einsatz von Luzernesilage als Alternative zu Grassilage in maisbetonten Rationen auf die Futteraufnahme, die Milchleistung und Stoffwechselparameter von Milchkuhen mit hoher Leistung auswirkt. Daher wurden 3 Mischrationen (TMR) konzipiert, die als wesentliche Grundfutterkomponenten Maissilage in Kombination mit Grassilage (Mais, 41,5 bzw. 12% der Trockensubstanz (T) Mais- und Grassilage) oder (Gras, 18 bzw. 29% der T Mais- und Grassilage) oder Luzernesilage (Luzerne, 18 bzw. 29% der T Mais- und Luzernesilage) enthielten. Die Verdaulichkeit der Organischen Substanz, bestimmt mit Hammeln, betrug fur die Grassilage 77% und fur die Luzernesilage 65%. Die Rohnahrstoffverdaulichkeiten wurden fur die 3 TMR mit Hammeln gemessen und die aus den verdaulichen Rohnahrstoffen berechnete NEL betrug (in MJ/kg T) 7,1 (Mais), 7,2 (Gras) und 6,8 (Luzerne). Auf Basis einer chemischen Rohproteinfraktionierung wurde ermittelt, dass die Gehalte an nutzbarem Rohprotein (nXP) in allen Rationen mindestens 167 g/kg T betrugen und die ruminale N-Bilanz nicht negativ war. Die Rationen wurden uber einen Zeitraum von 169 Tagen an mindestens 28 Milchkuhe je Ration verfuttert. Futterverzehr, Leistungsdaten und Stoffwechselindikatoren wurden tierindividuell erfasst. In der Behandlung Luzerne war der Futterverzehr mit 23,2 kg T/Tag signifikant hoher als in den Behandlungen Gras (21,2 kg T/Tag) und Mais (22,6 kg T/Tag). Die tagliche Aufnahme an NEL und nXP war im Mittel des Versuches in der Behandlung Gras signifikant niedriger als in den beiden anderen Behandlungen. Die tagliche Milchmenge war in der Behandlung Mais (41,7 kg/Tag) signifikant hoher als in der Behandlung Gras (37,3 kg/Tag) und in der Behandlung Luzerne (38,5 kg/Tag), verbunden mit signifikant geringeren Milchfettgehalten in der Behandlung Mais (3,5% im Vergleich zu 3,9% bei Gras und Luzerne). Der Milcheiweisgehalt war nicht von der Behandlung beeinflusst. Der Acetongehalt der Milch war zwischen den Behandlungen nicht signifikant verschieden, in der Behandlung Mais aber tendenziell geringer. Der Gehalt an s-Hydroxybutyrat im Blut war zu Laktationsbeginn in der Behandlung Luzerne signifikant hoher als in den beiden anderen Behandlungen. Dieser Unterschied bestand im weiteren Verlauf der Laktation nicht mehr. Messungen der Ruckenfettdicke deuten einen zwischen den Behandlungen weitgehend ahnlichen Verlauf von Energiemobilisation und -retention im Verlaufe des Versuches an. Daher kann Luzernesilage trotz der relativ geringen Verdaulichkeit auch in Rationen fur Hochleistungskuhe als eine geeignete Grundfutterkomponente angesehen werden.

A study with high-yielding dairy cows was re-analysed in order to test the suitability of lucerne silage separately for primi- and multiparous cows as an alternative to grass silage in maize-based total mixed rations (TMR). Lactation curves were fitted using random regression test-day models for energy corrected milk (ECM) and dry matter intake (DMI) as well as for number and duration of feeder visits (NFV and DFV, respectively). Existing models for ECM and DMI were extended by animal-specific random effects, which were formulated in their dependency on days in milk. For NFV and DFV random regression models were applied for the very first time. The chosen approach of statistical analysis permitted comparisons of the lactation curves as well as of least square means for sub-periods to answer nutritional questions. Whilst primiparous cows had generally lower DMI and ECM as compared to multiparous cows, only in primiparous cows a negative effect of lucerne TMR on ECM was observed, especially in early lactation. Nutritional factors should be rejected because of very similar ECM between the various TMR in multiparous cows. Traits of feeding behaviour indicated that particle size could contribute to the decreased ECM. Even more impact on the lower ECM should be addressed to domination behaviour of multiparous cows. The resulting restlessness of primiparous cows caused a reduced intake per minute spent at the feeder. Further studies should focus on optimising the proportion and chopping length of lucerne in the diet and to improve flock management to maximise feed intake of primiparous cows. Generally, statistical analysis of lactation data became a very complex issue. It seems inevitable that nutritionists and statisticians team up to address this problem.

The aim of the present study was to examine the effects of an exogenous fibrolytic enzyme product applied to a total mixed ration (TMR) prior to feeding on ruminal fermentation, microbial protein synthesis, nutrient digestion, and milk yield and composition. Six multiparous lactating Holstein cows (598 +/- 29 kg initial live weight and 98 +/- 30 days in milk) fitted with rumen and duodenal cannulae were allocated to two treatments in a crossover design over three consecutive 28-d periods. The TMR containing 50% concentrates, 30% corn silage and 20% grass silage on dry matter (DM) basis, was mixed once daily and fed twice a day. Treatments were TMR alone (Control) or TMR with an enzyme product containing primarily cellulase and xylanase activities (9000 U endo-1,4-beta glucanase, 24000 U endo-1,3(4)-beta glucanase and 40000 U 1,4-beta xylanase per ml). The enzyme product was applied at a rate of 6.2 ml/kg TMR (DM basis). It was diluted at a rate of 1:5 with water and applied daily to the TMR. During the control period the cows received a TMR supplemented with 36 ml water/kg TMR on DM basis. Duodenal digesta flow was measured using Cr2O3 as flow marker and microbial protein in the duodenal digesta was estimated by near-infrared spectroscopy (NIRS). There were no significant differences in ruminal pH-values, NH3-N concentrations, total SCFA concentrations and molar proportions of SCFA. No treatment effects on microbial N flow to the duodenum and efficiency of microbial protein synthesis were observed. The apparent ruminal digestibilities of DM, organic matter, NDF and ADF, milk yield and composition were also not affected by the enzyme supplementation. In this study the application of exogenous fibrolytic enzymes fed to dairy cows did not show a significant effect on any parameter tested.

Summary The objective was to study whether thermally treated lupins (TTL) can replace solvent-extracted soybean meal (SBM) and rapeseed meal (RSM) in dairy cow rations. Three total mixed rations (TMR) were used. They differed in the inclusion of the main protein feeds (TTL alone, TTL + RSM and RSM + SBM) but were equal in organic matter digestibility and metabolizable energy content. In vitro organic matter fermentation was not significantly different between the TMR. Efficiency of microbial crude protein (MCP) synthesis was significantly higher for TMR RSM + SBM than for TTL. In vitro gas production potential was similar for the three TMR. The maximal rate of gas production was achieved later in TMR TTL than in RSM + SBM. Feed intake of dairy cows was significantly lower when TMR TTL was fed than when TMR TTL + RSM or RSM + SBM were fed. Milk yield was significantly lower with the high inclusion rate of TTL in comparison with the other TMR. The contents of milk protein and milk fat were significantly lower when the two TTL containing TMR were fed in comparison with the RSM + SBM ration. Effects of TTL inclusion on MCP synthesis may affect the amino acid supply to the duodenum of cows to a greater extent than differences in the degradability of feed proteins.