Influence of different dietary fibre contents in the diet on feather pecking, locomotor activity and performance of laying hens.

1. This study investigated the effects of three diets with increasing proportions of insoluble dietary fibre (3%, 6% and 9%) but with similar metabolisable energy on behaviour, plumage condition and laying performance of Lohmann Tradition hens.2. At 21 weeks of age, four groups of 20 hens each (= four replicates/treatment) were randomly assigned to one of the three feeding treatments and exclusively fed with their assigned feed until the end of the laying period.3. Severe feather pecking decreased with increasing fibre content (3%: 0.78 pecks/30 min/hen, 6%: 0.31, 9%: 0.12; P < 0.0001). In contrast, no effect of fibre was seen for gentle feather pecking (P = 0.19) and aggressive pecking (P = 0.84). The number of free feathers in the littered area increased with increasing fibre content (3%: 0.06 feathers/625cm2/hen, 6%: 0.09, 9%: 0.16; P = 0.0074). Over time, plumage quality worsened in all hens, but was consistently better with increasing fibre content (fibre content × sampling period; P < 0.0001). Locomotor activity was similar across all treatments, except for a slight decrease in hens fed the 3% fibre diet at the end of the experimental period. No effect of fibre content on hens' weight (P = 0.75) was detectable. Similarly, performance did not differ between hens fed varying dietary fibre.4. The results supported the assumption that increasing dietary fibre helps to reduce the risk for the occurrence of feather pecking in laying hens, i.e. improve well-being, while having no negative effects on performance.

Haematological and febrile response to Escherichia coli lipopolysaccharide in 12-week-old cockerels of genetically diverse layer lines fed diets with increasing L-arginine levels.

Due to its decisive function in the avian metabolic, endocrine and immune system L-arginine (Arg) is dietary indispensable for chickens. In 12-week-old cockerels of two high- and two low-performing purebred layer lines, the effects of increasing dietary Arg on the haematological and febrile response were studied over 48 h after single lipopolysaccharide (LPS) injection. The offered diets contained Arg equivalent to 70%, 100% and 200% of recommended supply. Pathophysiological alterations in weight gain, feed intake, body temperature and differential blood count were examined in comparison with their physiological initial values. Within the first 24 h after LPS injection, cockerels reduced feed intake and lost body weight subsequently. Thereby, low-performing genotypes lost body weight to a lesser extent than high-performing ones. The loss of body weight was further intensified by deficient dietary Arg. Within the following 24 h, cockerels recovered by improving feed intake and weight gain. Furthermore, LPS induced genotype-specific fever response: both brown genotypes showed initial hypothermia followed by longer lasting moderate hyperthermia, whereas the white genotypes exhibited biphasic hyperthermia. Fever response was accompanied by significant changes in differential blood counts. Characterized by lymphopenia and heterophilia, a severe leucopenia was observed from 4 to 8 h after LPS injection and replaced by a marked leucocytosis with longer lasting monocytosis up to 48 h after LPS injection. Under given pathophysiological conditions, deficiently Arg-supplied cockerels showed higher total leucocyte counts than adequately and excessively Arg-supplied cockerels. However, deficient and surplus dietary Arg tended to cause higher ratios between heterophils and lymphocytes. To conclude, present results confirmed that LPS induced numerous immunological changes in 12-week-old cockerels and emphasized that chicken's genotype is a source of variation to be considered for immunological studies. Deficient dietary Arg intensified acute changes in differential blood counts and weight gain during LPS-induced inflammation.

Metabolic and clinical response to Escherichia coli lipopolysaccharide in layer pullets of different genetic backgrounds supplied with graded dietary L-arginine.

L-arginine (Arg) is an essential amino acid in birds that plays a decisive role in avian protein synthesis and immune response. Effects of graded dietary Arg supply on metabolic and clinical response to Escherichia coli lipopolysaccharide (LPS) were studied over 48 hours after a single intramuscular LPS injection in 18-week-old genetically diverse purebred pullets. LPS induced a genotype-specific fever response within 4 hours post injectionem. Whereas brown genotypes showed an initial hypothermia followed by longer-lasting moderate hyperthermia, white genotypes exhibited a biphasic hyperthermia without initial hypothermia. Furthermore, within 2 hours after LPS injection, sickness behavior characterized by lethargy, anorexia, intensified respiration, and ruffled feathers appeared, persisted for 3 to 5 hours and recovered 12 hours post injectionem. The varying grades of Arg did not alter the examined traits named above, whereas insufficient Arg reduced body growth and increased relative weights of liver and pancreas significantly. At 48 hours post injectionem, increased relative weights of liver and spleen were also found in LPS treated pullets, whereas LPS decreased those of pancreas, bursa, thymus, and cecal tonsils. Moreover, LPS lowered the sum of plasma amino acids and decreased plasma concentrations of Arg, citrulline, glutamate, methionine, ornithine, phenylalanine, proline, tryptophan, and tyrosine, and increased those of aspartate, glutamine, lysine, 1- and 3-methyl-histidine. Elevating concentrations of dietary Arg led to increasing plasma concentrations of Arg, citrulline, ornithine, and 3-methyl-histidine subsequently. As quantitative expression of LPS-induced anorexia, proteolysis, and the following changes in plasma amino acids, pullets showed a significant decrease of feed and nitrogen intake and catabolic metabolism characterized by negative nitrogen balance and body weight loss in the first 24 hours post injectionem. Pullets recovered from the challenge within the second 24 hours post injectionem and changed to anabolism with re-increased feed and nitrogen intake, positive nitrogen retention, and weight gain. To conclude, present results confirmed that LPS induced numerous metabolic and physiological changes in pullet's genotypes, whereas dietary Arg affected the examined traits only slightly.

The effect of various iodine supplementations and two different iodine sources on performance and iodine concentrations in different tissues of broilers.

1. The objective of this study was to determine the influence of iodine (I) supplementation of feed, within the range of the European guidelines, on the performance of broiler chickens and I transfer into different organs and tissues, especially meat. The main emphasis was to assess whether broiler meat could be enriched and used as an I source in human nutrition. 2. Two experiments were performed, one with KI and the other with Ca(IO(3))(2). For each experiment, 288 d-old broiler chicks were divided into 4 groups (72 birds/group) and fed on diets with supplementations between 0 and 5 mg I/kg feed. The birds were reared to 35 d of age under standard conditions. Six birds per group were slaughtered at 35 d and samples of blood, thyroid gland, liver, pectoral and thigh meat taken. 3. Iodine treatment did not significantly affect the growth and slaughter performance of the broiler chickens. In all investigated parameters, I concentrations increased significantly with increasing I intake of the animals. The lowest I concentrations were measured in the meat, but they were considerably higher in blood serum, liver and thyroid gland. Since the I content of meat was still low in the highest supplemented group (highest median concentration: 67·8 µg I/kg thigh meat), there is no evidence that this could substantially improve I supply in human nutrition.

Effects of an active immunization on the immune response of laying Japanese quail (Coturnix coturnix japonica) fed with or without genetically modified Bacillus thuringiensis-maize.

Potentially adverse effects of diets containing transgenic plants are a concern for many consumers, particularly in Europe. For Bacillus thuringiensis-maize, several studies in livestock and poultry showed that the zootechnical data provide no indication for such adverse effects. These studies were all done in homeostatic situations; it remained open whether a deflection of the regulatory physiological systems might yield divergent dynamic responses in B. thuringiensis-maize-fed animals. We therefore tested the effect of an active immunization using BSA as antigen in a feeding regimen with or without B. thuringiensis-maize using quail as a model organism. Newly hatched Japanese quail were randomly allocated to 2 groups (n=120 per group) fed with diets containing either B. thuringiensis-maize or isogenic maize of the same cultivar. The diets did not differ in concentrations of the mycotoxins deoxynivalenol and zearalenone, which were both far below guidance values. After 16 wk on the experimental diets, one-half of each group was immunized against BSA. The remaining birds were injected with saline. Thirty-six hours after the injection, half of the BSA-injected subgroup (n=30) and half of the saline subgroup (n=30) from B. thuringiensis-maize- and isogenic-fed birds were killed and blood samples were collected and analyzed for serum zinc levels, indicative for acute phase response. For determining IgY-mediated immune responses, eggs were collected every other week for 6 wk after the injections from the remaining birds and total IgY concentrations and BSA-specific IgY titers were measured in egg yolk. The BSA injections did not elicit significant decreases of serum zinc concentrations. The serum zinc levels were significantly higher in B. thuringiensis-maize-fed quail. Expectedly, total IgY as well as BSA-specific IgY titers increased with time in the BSA-immunized quail. The response of both variables to the BSA injection did not differ between the feeding groups. Our results indicate that feeding of B. thuringiensis-maize does not impair the immune system of Japanese quail and thus gives no indication for respective concerns.

Serum chemistry reference values in adult Japanese quail (Coturnix coturnix japonica) including sex-related differences.

Serum chemistry reference values may provide useful information about the physical condition of individuals, making them a useful tool in differentiating normal and healthy animals from abnormal or diseased states. For Japanese quail that are used for producing eggs and meat for human consumption and also as laboratory animals, we aimed to extend the available array of reference values and to compare 16-wk-old adult male versus female birds. In the present study, clinical chemistry data (albumin, total protein, glucose, uric acid, cholesterol, bilirubin, cholinesterase, creatinine, triglycerides, alanine aminotransferase, aspartate aminotransferase, and gamma-glutamyltransferase) in blood serum from up to 125 male and 151 female Japanese quail were established. Statistical comparisons were made between male and female birds. Aspartate aminotransferase, alanine aminotransferase, glucose, cholinesterase, and bilirubin values were higher (P < 0.01) in males, whereas females had higher (P < 0.05) concentrations of albumin, total protein, gamma-glutamyltransferase, total cholesterol, and triglycerides. No significant sex-based differences were observed for creatinine and uric acid. The reference values provided are relevant in particular for the use of quail as laboratory animals when responses to specific treatments have to be monitored and appraised.

Influence of temperature stimulation during the last 4 days of incubation on secondary sex ratio and later performance in male and female broiler chicks.

1. In 6 incubation trials a total of 9883 eggs (Ross 308) were incubated from d 1 to 17 under normal incubation conditions (37.2-37.4 degrees C) and then sorted into three hatch incubators (control: 37.2-37.4 degrees C; chronic warm incubation: 38.2-38.4 degrees C, 24 h daily; short-term warm stimulation: 38.2-38.4 degrees C, 2 h daily) in incubation trials 1 and 2 or two hatch incubators (control and short-term warm stimulation) in trials 3-6. 2. The one-day-old chicks were selected by sex and chick quality was analysed in random samples using the Pasgar score. A total of 120 male and 120 female one-day-old chickens from each incubator were used for a 35-d fattening period. 3. Neither chronic nor short-term increase in incubation temperature had a negative effect on hatchability and chick quality. Short-term warm stimulation improved hatchability by more than 1.5% and was associated with a significantly higher proportion of hatched male chicks. 4. In the subsequent broiler growth trial, the mean daily weight gain of the short-term warm stimulated male broiler chicks was significant higher than for the control group, which results in a body weight increase of 2.9%. 5. Feed conversion (feed:gain ratio) of the short-term warm stimulated male and female broilers was significantly lower than in the males and females of the control and chronic warm incubated groups. 6. In conclusion, an incubation temperature profile which includes short-term temperature variation can be important in improving poultry performance (European patent pending since March 2008).

Effect of addition of a detoxifying agent to laying hen diets containing uncontaminated or Fusarium toxin-contaminated maize on performance of hens and on carryover of zearalenone.

16-wk experiment with laying hens was carried out to examine the effects of feeding of mycotoxin-contaminated maize (CM) on performance, nutrient digestibility, weight of organs, serum chemical parameters, and antibody titers to Newcastle disease virus (NDV) in serum. Also tested were fimbrien antigen K88 in egg yolk and zearalenone (ZON) residues in eggs and tissues. The Fusarium-toxin-contaminated maize contained 17,630 microg deoxynivalenol and 1,580 microg ZON/kg. Moreover, Mycofix Plus (MP), a so-called detoxifying agent, was added to both the uncontaminated control (UCM) and to the CM diet (70% dietary maize inclusion). Each of the four resulting diets (UCM, UCM-MP, CM, CM-MP) was tested on 25 laying hybrids (Lohmann Brown). Feeding of the CM diets significantly depressed feed intake compared to the control groups by approximately 5%. This was mainly due to the effects observed at the beginning of the experiment. Daily egg mass production/hen was 56.6, 58.4, 53.9, and 55.2 g in groups UCM, UCM-MP, CM and CM-MP, respectively. Nutrient digestibility and metabolizability of gross energy were slightly depressed by feeding the CM diets and improved by MP addition. Feeding of the CM diets resulted in a significant decrease in serum titers to NDV and to an increase in yolk titers to antigen K88. No residues of ZON or of its metabolites were found in yolk, albumen, abdominal fat, breast meat, follicles greater than 1 cm in diameter, ovaries including follicles smaller than 1 cm in diameter, magnum, and serum. ZON and alpha-zearalenol (alpha-ZOL) were detected in livers of hens fed the CM diets at mean concentrations of 2.1 and 3.7 microg/kg, respectively. It was concluded that feeding maize which was highly contaminated with Fusarium mycotoxins adversely influenced performance of hens and modulated immune response. At the given level of zearalenone and at the indicated detection limits, no residues of ZON and its metabolites were found in eggs. The effects of the tested detoxifying agent were quite mycotoxin-independent.

-Secondary cerebral stress of systemic origin in children with severe craniocerebral injuries-. / Agressions cérébrales secondaires d'origine systémique chez les enfants traumatisés craniocérébraux graves.

OBJECTIVE: To assess incidence of secondary brain insults of systemic origin (SBISOs) such as arterial hypotension, hypoxaemia, hypercarbia, and anaemia in severely head injured children; to assess their impact on mortality and morbidity in the short- and long-term. STUDY DESIGN: Prospective, open study covering a 24-month period. PATIENTS: Seventy-one children, under 15 years of age, admitted to a trauma centre for severe brain injury. METHOD: Analysis of SBISOs and outcome. RESULTS: Twenty-five children were admitted with SBISOs. The mortality rate was 37%. After hospitalization, 84% of the children with SBISOs vs 46% without SBISOs had severe disability (Glasgow outcome score = 1, 2 and 3). After 1 year, 20 out of the 45 children still alive were contacted. One of the four with SBISOs communicated a bad recovery. Fifteen children without SBISOs presented good recovery: GOS = 4-5, paediatric overall performance category (POPC scale) = 1-2. CONCLUSION: Hypotension was associated with significant increase in mortality (x 3.6) in children with severe head injury. The consequences were worse when anaemia was associated.

[The effect of palm oil and safflower oil in the feed of parent fattening hens on fertility, hatchability and growth of progeny]. / Untersuchungen zum Einfluss von Palmfett und Distelöl im Futter von Mastelterntierhennen auf Befruchtung, Schlupffähigkeit und Wachstum der Nachkommen.

The aim of two experiments with broiler breeder hens was to evaluate the effect of diets containing palm butter or safflower oil (25 g and 50 g/kg feed, resp.) on fertility, hatchability and growth of progeny. Especially the incorporation of oleic and linoleic acid in egg yolk reflected the dietary fatty acid source. Eggs were collected and stored in the incubator at a hen age of 31, 40, 50, and 60 weeks. Hatched chicks were reared over 5 weeks. The number of fertile eggs (Experiment 1 and 2, 75 and 88%, resp.) differed between the experiments (P < or = 0.05). Neither embryonic mortality nor hatchability (Experiment 1 and 2, 76 and 78%, resp.) were significantly affected by fatty acid composition of yolk. No clear maternal dietary effect was recorded on chicken weight at hatching (Experiment 1 and 2, 43.3 g and 43.7 g, resp.) and at 35 days of age (Experimental 1 and 2, 1676 g and 1764 g, resp.) The fatty acid composition in the analysed egg yolk sac of chicks showed a different fatty level but corresponded to fatty acid composition of breeding eggs before incubation. According to a decreased level of docosahexaenoic acid in egg yolk due to increased incorporation of linoleic acid, the content of this fatty acid was also diminished in phospholipids of the brain of chicken on days 1 and 5 after hatching.

[Nutrition of the cat]. / Zur Ernährung der Katze.

The requirement of the cat in respect to protein, energy, vitamins and minerals are presented. The special requirements of this carnivore appear to be due to the loss or charge of certain metabolic processes which are normally present in species such as the dog.

[The protein turnover of different leghorn hybrids]. / Untersuchungen zum Eiweissumsatz verschiedener Leghornhybriden.

After N-balance experiments with leghorn-hens of five different genetic origins in the top laying period, the advanced laying period as well as at the end of the laying period and with feeding of soybean meal/fish meal protein, the nitrogen maintenance requirement per live weight kg0.67 was ascertained regressively by approximation of the N-balance from N-increasing experiments to an exponential function. The Net Protein Utilization (PNu) curve and the apparent Net Protein Utilization (PEW) curve could be described as utilisation values from the N-retention curve (e-function). Moreover the relation between N-intake/LW kg0.67 and egg-N-discharge/LW kg0.67 from N-balance made it possible to estimate N-retention in the body. Finally, capability of the five origins at equal protein and S-AA intake respectively were compared.

[Effect of graded nitrogen supplements on egg protein synthesis and body protein retention in broiler hens]. / Untersuchungen zum Einfluss gestaffelter N-Gaben auf die Eiproteinsynthese und den Körperproteinansatz der Broilerhenne.

In the top laying period (29th/30th week of life) egg protein synthesis and protein retention in the bodies of laying hens were ascertained. Based on egg-N analyses, the relation between N-intake/live weight0.67kg and egg-N discharge/kg LW0.67kg was regressively calculated and described. The subtraction of egg-N discharge/LW0.67kg from N-balance/LW0.67kg made it possible to estimate N-retention/LW0.67kg in the body. From the intersection of this curve with the chi-axis it follows that the broiler hen meets the N-requirement for maintenance and egg production with a daily consumption of 1,264.7 mg N/LW0.67kg, which corresponds to 15.8 g crude protein, and then neither loses nor retains body protein. At a daily intake of this amount of CP (15.8 g) the broiler hen produces 44.1 g egg per day. An energy intake of more than 70 EFUhen/animal and day resulted in fat retention in the broiler hen.

[Protein utilization as well as crude protein and amino acid requirements of broiler hens]. / Untersuchungen zur Eiweissverwertung sowie zum Rohprotein- und Aminosäurenbedarf der Broilerhenne.

After N-balance experiments with broiler hens in the top laying period and the feeding of soybean coarse meal/fish meal protein the protein utilisation values were calculated. The PNu curve and the PEW curve could be described as utilisation values from the N-retention curve (e-function). At an intake of N at which the hen neither decomposed nor retained protein, the utilisation (PNu) for maintenance and egg production was 55.3% and the utilisation of feed protein for egg production 49.4%. Maximum PEW 34.3% could only be ascertained at an N-intake/LW0.67kg of 1500 mg. The corresponding crude protein quota of 18.7 g recommended as crude protein requirement is calculated from this N-quota (xm) and a live weight of the broiler hen of 2804 g. For the same N-quota (xm) and the same live weight of the hens this results in a necessary quota of S-AA of 694 mg per hen and day. Provided the daily feed intake is 145 g and thus the intake of crude protein 18.7 g and that of S-AA 694 mg per hen, the necessary crude protein content of the feed is 130 g per kg original substance and an S-AA concentration which is equivalent to 3.7% of the crude protein (in g/16 g N).

Evaluation of the non invasive TOBEC (total body electrical conductivity) procedure for prediction of chemical components of male broilers with special consideration of dietary protein level.

TOBEC (total body electrical conductivity) measurement as a non invasive procedure for the estimation of body chemical composition was used to calculate calibration curves for the prediction of crude protein mass (CPM), crude water mass (CWM), crude ash mass (CAM) and fat-free mass (FFM) of male broiler chickens. A growth experiment with 3 protein levels (130, 230 and 330 g CP/kg diet, isoenergetic with 13.3 MJ AMEN/kg) was combined with TOBEC measurements and body chemical analysis in order to obtain the values necessary for calibration. A total of 196 TOBEC measurements and body chemical analysis were undertaken in time intervals of two days beginning with batch until day 17 of age. Different dietary protein levels resulted in marked differences in body weights and body chemical compositions but in similar TOBEC-responses for a given mass of FFM, CPM, CAM or CWM. Values for birds fed a diet with 130 g CP/kg diet tended to be more variable. Linear broken relationships were found between FFM, CPM, CAM and CWM, respectively and TOBEC values (E#). A set of different regression equations is given and yielded high proportions of variance accounted for the piece wise regression model (R2 ranged from 0.83 to 0.99). In spite of these high determinations the prediction of crude fat mass (CFM) by subtracting the FFM from the body weight resulted in most cases in weak determinations between observed and predicted CFM (R2 ranged from 0.38 to 0.86). The highest R2 was observed when the E# was expressed per unit metabolic body weight to the power of 0.67 and regressed on FFM expressed to the same power. In conclusion, FFM, CPM and CWM may be predicted reasonably well by TOBEC. However, these high determinations are not high enough to predict CFM accurately. In addition, the application of such regressions to an individual bird seems to be impossible. Assessment for groups of animals should be possible if errors of estimation, standard deviations and differences to be detected are taken into account in the calculation of the number of birds necessary for the TOBEC measurements.

Vitamin E hypervitaminosis in laying hens.

The aim of this investigation was to contribute to the problem of overdosing vitamin E. A total of 80 laying hens, divided into 5 groups, were fed diets supplemented with 0, 100, 1000, 10,000 and 20,000 mg/kg vitamin E over a period of 20 weeks within two brooding tests. Laying performance and hatching parameters were registered. All vitamin E doses did not significantly influence health and performances of hens. Vitamin E content of eggs increased from 1 to 4, 21, 46 and 51 mg per egg with vitamin E supplementation. High doses decreased oxidative stability of abdominal fat, vitamin A concentration of liver and egg yolk colour. In both tests vitamin E supplements of 10,000 and 20,000 mg/kg feed resulted in a decrease of living hatched chicken, which demonstrated an adverse effect. Further studies seem to be necessary to explain the effect.

Investigations on metabolism of zearalenone in broilers.

Two experiments were carried out with male broilers to examine excretion kinetics of zearalenone (ZEA) and its metabolites (Exp. 1) and their occurrence in blood plasma and bile fluid (Exp.2) after a single oral dose of ZEA (approximately 6 µg/kg body weight) from naturally contaminated wheat. In addition, this ZEA bolus was administered either in absence or presence of a detoxifying agent (Mycofix® Plus, Biomin GmbH, Herzogenburg, Austria). Specimens were sampled at different times after ZEA bolus of up to 48 h. Excretion of ZEA and alpha-zearalenol as the only detectable metabolite of ZEA peaked at approximately 6.5 h after administration of the bolus. Cumulative excretion of both substances amounted approximately 58 % of ZEA intake after 48 h. Peak concentrations of ZEA and alpha-zearalenol in bile were detected in the time period of approximately 2 to 6 h after bolus whereas detection in plasma was not possible for each measurement point. Mycofix® Plus supplementation seemed to have only minor or no effects on the parameters examined.

Influence of high levels of vitamin E on semen parameters of cocks.

This study was an attempt to find whether the reproductive performance of cocks would be influenced by oral administration of different amounts of dietary vitamin E over a long period of time. For that purpose 60 cocks were divided into five dietary groups of 12 animals each, and supplemented with 0 (control group), 100, 1,000, 10,000 or 20,000 IU alpha-tocopherol/kg diet, respectively, over a period of 12 months. The effect on semen parameters and biochemical parameters measured in pooled semen samples and the weight of the testes were determined. The weight of testes decreased with increasing amounts of supplemented vitamin E. Volume, pH, colour, consistency and motility were not influenced by the diets, but density of ejaculate (sperm/microl), total amount of spermatozoa and morphology of sperm were significantly lowered by increasing amounts of supplemented vitamin E. The alpha-tocopherol concentration in ejaculates increased significantly in relation to the diet whereas phospholipid content and thiobarbituric acid-reactive substances (TBARS) of the semen samples decreased significantly with increasing vitamin E supplementation. The reproductive performance of cocks was negatively influenced by high doses of vitamin E although decreased TBARS indicated rising oxidative defence.

Nutrient balances as indicators for sustainability of broiler production systems.

1. Flock balances of nitrogen, phosphorus, zinc and copper (N, P, Zn, Cu) were calculated in order to evaluate environmental effects of three different broiler production systems (intensive indoor, free range and organic). 2. Nutrient gain in birds per unit nutrient intake (retention) in intensive indoor production was higher than in free range and organic production. 3. Nutrient surplus relative to nutrient retention was higher in organic production than in free range and intensive indoor production. 4. The main reasons for differences in nutrient efficiency between intensive indoor, free range and organic production were duration of growth period, strain of broilers and feeding strategy. 5. The calculation of whole farm indicators (livestock density, N and P excretions per hectare of farmland) demonstrates how defining system boundaries affects the outcome of an evaluation: organic farms had the smallest livestock densities and the lowest N and P excretions per hectare of farmland. 6. In the efforts to reach a more holistic evaluation of agricultural production systems, the definition of adequate system boundaries must be discussed. In addition to nutrient balances, further indicators of sustainability, such as human and ecological toxicity, should be considered.