Immunologisches Reaktionsvermögen als Indikator für Belastungen bei der Milchkuh

Mit ansteigenden Jahresmilchleistungen werden die Kühe einer hohen metabolischen Belastung ausgesetzt, die bei einer suboptimalen Gestaltung der Lebensbedingungen mit einer Erhöhung der Inzidenzrate von Faktorenkrankheiten einhergehen kann. Im Vordergrund der Untersuchungen stand die Frage, inwieweit metabolische Belastungszustände von Milchkühen in der Phase des Puerperiums und in Abhängigkeit von der Milchleistung sowie Belastungen durch eine klinische Erkrankung zu Beginn der Laktation mit Hilfe von Parametern der immunologischen Abwehr und der Reaktion des Immunsystems auf eine Challenge dargestellt werden können. In die Untersuchung wurden insgesamt 68 klinisch gesunde sowie 20 klinisch erkrankte Milchkühe der Rasse Holstein Friesian einbezogen. Die Untersuchungen erfolgten in den Zeiträumen 10-21 Tage sowie 14-15 Wochen nach der Kalbung. Dazu wurden an jeweils drei Untersuchungstagen (Tag 0, 2, 7) Blutproben aus der Vena jugularis entnommen. Zur Stimulierung des unspezifischen Immunsystems wurde in beiden Versuchszeiträumen an den Untersuchungstagen 0 und 2 der Paramunitätsinducer Zylexis® appliziert. Ferner wurde den Kühen zu Beginn der Laktation der Tollwutimpfstoff Rabisin® verabreicht. Für die Auswertung wurden die untersuchten Milchkühe in Gruppen unterteilt. Die klinisch gesunden Kühe wurden anhand der nach Fett und Eiweiß korrigierten 305-Tage-Leistung in die Gruppe M = mittleres Leistungsniveau (Milchmengenleistung 6.500-8.990 kg) und die Gruppe H = hohes Leistungsniveau (Milchmengenleistung 9.000-12.500 kg) aufgeteilt. Die klinisch erkrankten Kühe wurden in der Gruppe K zusammengefasst. Zur Beurteilung der Immunabwehr wurden die Parameter Phagozytoseaktivität der isolierten Neutrophilen Granulozyten, die Vollblutbakterizidie, die Lymphozytenproliferation mit den Mitogenen ConA, PHA und PWM sowie die spezifische Antikörperbildung gegen Tollwut untersucht. Anhand der Parameter Phagozytoseaktivität, Vollblutbakterizidie und Lymphozytenproliferation wurde zusätzlich die Reaktion auf die Challenge mit dem Paramunitätsinducer Zylexis® überprüft. Zur Erfassung der metabolischen Belastungszustände wurden verschiedene Stoffwechselparameter und hämatologische Parameter erfasst. Zu Beginn der Laktation konnten bei den Kühen in der mittleren und hohen Leistungsgruppe signifikant höhere Konzentrationen an ß-Hydroxybuttersäure und Freien Fettsäuren im Vergleich zu der Laktationsmitte festgestellt werden. Die Kühe mit einem hohen Leistungsniveau zeigten darüber hinaus eine signifikant höhere Bilirubinkonzentration am Laktationsanfang gegenüber der Laktationsmitte. Die mittlere Konzentration der freien Fettsäuren lag bei den Kühen in beiden Leistungsgruppen oberhalb des Referenzbereiches und wies auf eine negative Energiebilanz zu Laktationsbeginn hin. Die mittleren Konzentrationen bzw. Enzymaktivitäten der Parameter Cholesterol, Harnstoff, AST, GLDH, γ-GT, Gesamtprotein, Kalzium und Phosphor wiesen in der Laktationsmitte signifikant höhere Werte als am Laktationsanfang auf. Dabei lagen die mittleren Enzymaktivitäten von AST und GLDH sowie die Konzentrationen von Harnstoff und Gesamtprotein in der Laktationsmitte oberhalb des Referenzbereiches. Die untersuchten Stoffwechselparameter wurden durch die Challenge mit einem Paramunitätsinducer nicht signifikant beeinflusst. Hinsichtlich der Immunparameter zeigten die Milchkühe mit einem mittleren Leistungsniveau in Abhängigkeit vom Laktationszeitpunkt zu Beginn der Laktation eine signifikant höhere Phagozytoseaktivität gegenüber der Laktationsmitte (p < 0,05). Die Gruppe mit einem hohen Leistungsniveau wies dagegen keine signifikanten Unterschiede in der Phagozytoseaktivität zwischen den beiden Untersuchungszeiträumen auf. Bei den Immunparametern Vollblutbakterizidie und Lymphozytenproliferation konnten bei den Kühen beider Gruppen keine signifikanten Unterschiede in Abhängigkeit vom Laktationszeitpunkt festgestellt werden. Im Hinblick auf die Milchleistung wiesen die Kühe in den beiden Leistungsgruppen am Untersuchungstag 0 weder zu Beginn noch in der Mitte der Laktation signifikante Unterschiede bezüglich der untersuchten Immunparameter auf. Nach der Challenge durch den Paramunitätsinducer reagierten einzig die Kühe mit einer mittleren Leistung zu Beginn der Laktation auf die Challenge mit einer signifikanten Reduzierung der mittleren Phagozytoseaktivität von Tag 0 zu Tag 2 (p < 0,05). Bei den weiteren untersuchten Immunparametern konnten weder bei den Kühen mit einer mittleren noch mit einer hohen Leistung eine signifikante Reaktion auf die Challenge nachgewiesen werden. Die klinisch erkrankten Kühe zeigten im Vergleich zu den klinisch gesunden Kühen keine unterschiedlichen Konzentrationen bzw. Aktivitäten der untersuchten Stoffwechselparameter. Auch konnten anhand der immunologischen Parameter und der Reaktion auf die Challenge keine Unterschiede zwischen den klinisch gesunden Kühen festgestellt werden. Die in der vorliegenden Untersuchung geprüften metabolischen Belastungen konnten weder anhand der Immunparameter noch durch die Reaktion der Immunparameter auf eine Challenge dargestellt werden. Es wird geschlussfolgert, dass das immunologische Reaktionsvermögen nicht geeignet ist, um als Indikator für Belastungszustände bei der Milchkuh herangezogen zu werden.

Applying Least Absolute Shrinkage Selection Operator and Akaike Information Criterion Analysis to Find the Best Multiple Linear Regression Models between Climate Indices and Components of Cow’s Milk

This study focuses on multiple linear regression models relating six climate indices (temperature humidity THI, environmental stress ESI, equivalent temperature index ETI, heat load HLI, modified HLI (HLI new), and respiratory rate predictor RRP) with three main components of cow’s milk (yield, fat, and protein) for cows in Iran. The least absolute shrinkage selection operator (LASSO) and the Akaike information criterion (AIC) techniques are applied to select the best model for milk predictands with the smallest number of climate predictors. Uncertainty estimation is employed by applying bootstrapping through resampling. Cross validation is used to avoid over-fitting. Climatic parameters are calculated from the NASA-MERRA global atmospheric reanalysis. Milk data for the months from April to September, 2002 to 2010 are used. The best linear regression models are found in spring between milk yield as the predictand and THI, ESI, ETI, HLI, and RRP as predictors with p-value < 0.001 and R2 (0.50, 0.49) respectively. In summer, milk yield with independent variables of THI, ETI, and ESI show the highest relation (p-value < 0.001) with R2 (0.69). For fat and protein the results are only marginal. This method is suggested for the impact studies of climate variability/change on agriculture and food science fields when short-time series or data with large uncertainty are available.

The Effect of Climate Variability on Main Components of Cow Milk in Iran

The main purpose of this study is to assess the relationship between six bioclimatic indices for cattle (temperature humidity (THI), environmental stress (ESI), equivalent temperature (ESI), heat load (HLI), modified heat load (HLInew) and respiratory rate predictor(RRP)) and fundamental milk components (fat, protein, and milk yield) considering uncertainty. The climate parameters used to calculate the climate indices were taken from the NASA-Modern Era Retrospective-Analysis for Research and Applications (NASA-MERRA) reanalysis from 2002 to 2010. Cow milk data were considered for the same period from April to September when cows use natural pasture, with possibility for cows to choose to stay in the barn or to graze on the pasture in the pasturing system. The study is based on a linear regression analysis using correlations as a summarizing diagnostic. Bootstrapping is used to represent uncertainty estimation through resampling in the confidence intervals. To find the relationships between climate indices (THI, ETI, HLI, HLInew, ESI and RRP) and main components of cow milk (fat, protein and yield), multiple liner regression is applied. The least absolute shrinkage selection operator (LASSO) and the Akaike information criterion (AIC) techniques are applied to select the best model for milk predictands with the smallest number of climate predictors. Cross validation is used to avoid over-fitting. Based on results of investigation the effect of heat stress indices on milk compounds separately, we suggest the use of ESI and RRP in the summer and ESI in the spring. THI and HLInew are suggested for fat content and HLInew also is suggested for protein content in the spring season. The best linear models are found in spring between milk yield as predictands and THI, ESI,HLI, ETI and RRP as predictors with p-value < 0.001 and R2 0.50, 0.49. In summer, milk yield with independent variables of THI, ETI and ESI show the highest relation (p-value < 0.001) with R2 (0.69). For fat and protein the results are only marginal. It is strongly suggested that new and significant indices are needed to control critical heat stress conditions that consider more predictors of the effect of climate variability on animal products, such as sunshine duration, quality of pasture, the number of days of stress (NDS), the color of skin with attention to large black spots, and categorical predictors such as breed, welfare facility, and management system. This methodology is suggested for studies investigating the impacts of climate variability/change on food quality/security, animal science and agriculture using short term data considering uncertainty or data collection is expensive, difficult, or data with gaps.

Determination of subclinical metabolic disorders in transition dairy cows

Das Gesundheitsmanagement von Milchkühen hat in den vergangenen Jahren auf den landwirtschaftlichen Betrieben an Bedeutung gewonnen. Neben Präventionsmaßnahmen zur Gesunderhaltung der Tiere ist die frühzeitige und systematische Erkennung von Erkrankungen hierbei der Hauptbestandteil. Es zeigt sich vermehrt, dass vor allem Transitkühe verstärkt an Stoffwechselerkrankungen in sowohl klinischer als auch subklinischer Form erkranken. Letztere stellen ein hohes Risiko dar, zum einen weil subklinische Erkrankungen oftmals nur schwer oder gar nicht erkannt werden und zum anderen, weil sie in vielen Fällen die Grundlage für meist schwerwiegendere Folgeerkrankungen sind. In der vorliegenden Studie wird das Thema der Früherkennung von subklinischen Ketosen und der subakuten Pansenazidose behandelt. Verschiedene Methoden wurden unter praktischen Versuchsbedingungen auf ihre Tauglichkeit zur Krankheitserkennung hin geprüft. In einer ersten Studie wurde auf einem konventionellen Milchviehbetrieb ein Ketose-Monitoring bei frischlaktierenden Kühen ab Tag 3 postpartum durchgeführt. Insgesamt 15 Tiere waren an einer subklinischen Ketose erkrankt, was eine Aufkommensrate von 26% in den untersuchten Tieren bedeutete. Die Blutproben von insgesamt 24 Tieren wurden auf ihren IL-6-Gehalt untersucht. Von den untersuchten Tieren waren 14 Tiere erkrankt, 10 Tiere bildeten die gesunde Kontrollgruppe. Interleukin-6 wurde bestimmt, da dem Zytokin IL-6 in anderen Studien in Bezug auf Ketosen eine Rolle zugesprochen wurde. Die erwartete Erhöhung von IL-6 bei erkrankten Tieren konnte nicht festgestellt werden; die erkrankten Kühe zeigten vielmehr die niedrigsten IL-6 Werte der Studiengruppe. Insgesamt waren die IL-6 Konzentrationen auf einem niedrigen Niveau mit 27.2 pg/m l± 10.2. Es zeigte sich, dass die IL-6 Bestimmung im Blut hinsichtlich der Erkennung von subklinischen Ketosen nur eingeschränkt nutzbar ist. Es konnte ausschließlich eine schwache negative Korrelation zwischen Beta- Hydroxybutyrat (BHBA, Goldstandard für den Nachweis einer Ketose) und IL-6 detektiert werden. Zusätzlich zu den Blutanalysen wurde ebenfalls die tägliche Wiederkauaktivität mit dem „DairyCheck“ System bestimmt, welches kontinuierlich die charakteristischen Kaumuskelkontraktionen aufzeichnet und somit die Dauer des Wiederkäuens bestimmt werden kann. Es wurde geprüft, ob sich ketotische Tiere von nicht ketotischen Tieren hinsichtlich der täglichen Wiederkäuzeit unterscheiden. Milchkühe mit einer Ketose kauten im Schnitt 475 min/d ± 56 wieder, nach Genesung 497 min/d ± 48. Sie befanden sich somit im Durchschnitt immer unterhalb der gesunden Kontrollgruppe, welche 521 min/d ± 76 wiederkaute. Eine Korrelation zwischen der Wiederkauzeit und dem BHBA- Gehalt im Blut war nur sehr schwach ausgeprägt, nicht zuletzt da die Tiere generell eine hohe Variabilität in der Wiederkauaktivität zeigten. Bei einer weiteren Studie, ebenfalls auf einem Praxisbetrieb durchgeführt, wurde auf die Erkennung der subakuten Pansensazidose (SARA) fokussiert. Hierbei kam ein drahtloses, kommerziell verfügbares Bolussystem zum Einsatz, welches den pH Wert kontinuierlich im Retikulorumen misst. Es macht die Erkennung einer SARA auch unter Praxisbedingungen ohne invasive Methoden wie der Punktion möglich. Das Bolussystem wurde 24 Milchkühen kurz vor der Abkalbung oral eingegeben, um den pH-Wert während der gesamten Transitphase messen und überwachen zu können. Während in der Trockenstehphase nur vereinzelte SARA Fälle auftraten, erlitt ein Großteil der untersuchten Tiere in der Frühlaktation eine SARA. Auf Grundlage von pH-Werten von laktierenden Milchkühen, wurde zusätzlich eine Sensitivitätsanalyse von verschieden, bereits eingesetzten Nachweismethoden durchgeführt, um die Tauglichkeit für die SARA-Diagnostik zu untersuchen. Es handelte sich hierbei zum einen um einen SARA-Nachweis unter Heranziehung von Einzelwerten, Fress- und Wiederkäuzeiten, sowie ausgewählten Milchinhaltsstoffen und der Milchmenge. Die Analyse ergab, dass nahezu alle Nachweismethoden im Vergleich zur Langzeitmessung nur eingeschränkt zur SARA-Diagnostik nutzbar sind. In einem weiteren Teil der Studie wurde eine Kotfraktionierung bei den gleichen Tieren durchgeführt, um damit SARA-Tiere auch mittels der Kotanalyse erkennen kann. Es konnte gezeigt werden, dass zum einen die Ration einen Einfluss auf die Kotzusammensetzung hat (Trockensteherration versus Ration für Laktierende) zum anderen aber auch, dass eine SARA die Zusammensetzung des Kotes verändert. Hierfür wurden Kotproben ausschließlich von laktierenden Kühen untersucht, sodass der Einfluss der Ration ausgeschlossen werden konnte. Erhöhte Faseranteile im Kot von SARA - Kühen gaben Hinweis auf eine verminderte Verdaulichkeit. Dabei erwies sich vor allem die Hemizellulose als guter Parameter, um auf eine SARA schließen zu können. Die Versuchsbedingungen ließen es ebenfalls zu, die pH-Verläufe der Tiere in der Frühlaktation zu untersuchen. Eine Clusteranalyse von pH-Werten der ersten 12 Tage postpartum zeigte, dass die untersuchten Tiere trotz gleicher Haltungs- und Fütterungsbedingungen unterschiedliche pH-Wert Verläufe entwickelten. So gab es eine Gruppe von Milchkühen, die den pH-Wert stabil halten konnte, während die restlichen pH-Abfälle in verschiedenen Verläufen und Intensitäten aufzeigten. Es konnte ebenfalls aufgezeigt werden, dass Tiere innerhalb der Testherde unterschiedliche Schweregrade der SARA entwickelten. Auch in dieser Studie wurde deutlich, dass Tiere scheinbar unterschiedliche Möglichkeiten haben, auf ihre Umwelt zu reagieren, bzw. suboptimalen Bedingungen entgegenwirken zu können. Zusammengefasst wurden verschiedene Methoden zur Ketose- und SARA- Erkennung geprüft, von denen nur einzelne für die Praxis zu empfehlen sind. Die Variabilität der Tiere, sowohl bei der Ausprägung der Erkrankungen als auch bei den gemessenen Parametern verdeutlicht die Notwendigkeit, diese im Herden- und Gesundheitsmanagement in Zukunft stärker zu berücksichtigen.

Effect of management strategies on the performance of ruminant livestock production systems and the safety of plant and animal products in the city of Sikasso, Mali

The regional population growth in West Africa, and especially its urban centers, will bring about new and critical challenges for urban development policy, especially in terms of ensuring food security and providing employment for the growing population. (Peri-) urban livestock and vegetable production systems, which can contribute significantly to these endeavours, are limited by various constraints, amongst them limited access to expensive production factors and their (in)efficient use. To achieve sustainable production systems with low consumer health risks, that can meet the urban increased demand, this doctoral thesis determined nutrient use efficiencies in representative (peri-) urban livestock production systems in three West African cities, and investigated potential health risks for consumers ensuing from there. The field study, which was conducted during July 2007 to December 2009, undertook a comparative analysis of (peri-) urban livestock production strategies across 210 livestock keeping households (HH) in the three West African cities of Kano/Nigeria (84 HH), Bobo Dioulasso/Burkina Faso (63 HH) and Sikasso/Mali (63 HH). These livestock enterprises were belonging to the following three farm types: commercial gardening plus field crops and livestock (cGCL; 88 HH), commercial livestock plus subsistence field cropping (cLsC; 109 HH) and commercial gardening plus semi-commercial livestock (cGscL; 13 HH) which had been classified in a preceding study; they represented the diversity of (peri-) urban livestock production systems in West Africa. In the study on the efficiency of ruminant livestock production, lactating cowsand sheep herd units were differentiated based on whether feed supplements were offered to the animals at the homestead (Go: grazing only; Gsf: mainly grazing plus some supplement feeding). Inflows and outflows of nutrients were quantified in these herds during 18 months, and the effects of seasonal variations in nutrient availability on animals’ productivity and reproductive performance was determined in Sikasso. To assess the safety of animal products and vegetables, contamination sources of irrigated lettuce and milk with microbiological contaminants, and of tomato and cabbage with pesticide residues in (peri-) urban agriculture systems of Bobo Dioulasso and Sikasso were characterized at three occasions in 2009. Samples of irrigation water, organic fertilizer and ix lettuce were collected in 6 gardens, and samples of cabbage and tomato in 12 gardens; raw and curdled milk were sampled in 6 dairy herds. Information on health risks for consumers of such foodstuffs was obtained from 11 health centers in Sikasso. In (peri-) urban livestock production systems, sheep and goats dominated (P<0.001) in Kano compared to Bobo Dioulasso and Sikasso, while cattle and poultry were more frequent (P<0.001) in Bobo Dioulasso and Sikasso than in Kano. Across cities, ruminant feeding relied on grazing and homestead supplementation with fresh grasses, crop residues, cereal brans and cotton seed cake; cereal grains and brans were the major ingredients of poultry feeds. There was little association of gardens and livestock; likewise field cropping and livestock were rarely integrated. No relation existed between the education of the HH head and the adoption of improved management practices (P>0.05), but the proportion of HH heads with a long-term experience in (peri-) urban agriculture was higher in Kano and in Bobo Dioulasso than in Sikasso (P<0.001). Cattle and sheep fetched highest market prices in Kano; unit prices for goats and chicken were highest in Sikasso. Animal inflow, outflow and dairy herd growth rates were significantly higher (P<0.05) in the Gsf than in the Go cattle herds. Maize bran and cottonseed expeller were the main feeds offered to Gsf cows as dry-season supplement, while Gsf sheep received maize bran, fresh grasses and cowpea pods. The short periodic transhumance of Go dairy cows help them maintaining their live weight, whereas Gsf cows lost weight during the dry season despite supplement feeding at a rate of 1506 g dry matter per cow and day, resulting in low productivity and reproductive performance. The daily live weight gains of calves and lambs, respectively, were low and not significantly different between the Go and the Gsf system. However, the average live weight gains of lambs were significantly higher in the dry season (P<0.05) than in the rainy season because of the high pressure of gastrointestinal parasites and of Trypanosoma sp. In consequence, 47% of the sheep leaving the Go and Gsf herds died due to diseases during the study period. Thermo-tolerant coliforms and Escherichia coli contamination levels of irrigation water significantly exceeded WHO recommendations for the unrestricted irrigation of vegetables consumed raw. Microbial contamination levels of lettuce at the farm gate and the market place in Bobo Dioulasso and at the farm gate in Sikasso were higher than at the market place in Sikasso (P<0.05). Pesticide residues were detected in only one cabbage and one tomato sample and were below the maximum residue limit for consumption. Counts of thermo-tolerant coliforms and Escherichia coli were higher in curdled than in raw milk (P<0.05). From 2006 to x 2009, cases of diarrhea/vomiting and typhoid fever had increased by 11% and 48%, respectively, in Sikasso. For ensuring economically successful and ecologically viable (peri-) urban livestock husbandry and food safety of (peri-) urban foodstuffs of animal and plant origin, the dissemination and adoption of improved feeding practices, livestock healthcare and dung management are key. In addition, measures fostering the safety of animal products and vegetables including the appropriate use of wastewater in (peri-) urban agriculture, restriction to approve vegetable pesticides and the respect of their latency periods, and passing and enforcement of safety laws is required. Finally, the incorporation of environmentally sound (peri-) urban agriculture in urban planning by policy makers, public and private extension agencies and the urban farmers themselves is of utmost importance. To enable an efficient (peri-) urban livestock production in the future, research should concentrate on cost-effective feeding systems that allow meeting the animals’ requirement for production and reproduction. Thereby focus should be laid on the use of crop-residues and leguminous forages. The improvement of the milk production potential through crossbreeding of local cattle breeds with exotic breeds known for their high milk yield might be an accompanying option, but it needs careful supervision to prevent the loss of the local trypanotolerant purebreds.

A pilot investigation of the relationship between climate variability and milk compounds under the bootstrap technique

This study analyzes the linear relationship between climate variables and milk components in Iran by applying bootstrapping to include and assess the uncertainty. The climate parameters, Temperature Humidity Index (THI) and Equivalent Temperature Index (ETI) are computed from the NASA-Modern Era Retrospective-Analysis for Research and Applications (NASA-MERRA) reanalysis (2002–2010). Milk data for fat, protein (measured on fresh matter bases), and milk yield are taken from 936,227 milk records for the same period, using cows fed by natural pasture from April to September. Confidence intervals for the regression model are calculated using the bootstrap technique. This method is applied to the original times series, generating statistically equivalent surrogate samples. As a result, despite the short time data and the related uncertainties, an interesting behavior of the relationships between milk compound and the climate parameters is visible. During spring only, a weak dependency of milk yield and climate variations is obvious, while fat and protein concentrations show reasonable correlations. In summer, milk yield shows a similar level of relationship with ETI, but not with temperature and THI. We suggest this methodology for studies in the field of the impacts of climate change and agriculture, also environment and food with short-term data.

Heat stress response for physiological traits in dairy and dual purpose cattle populations on phenotypic and genetic scales

The main objective of this thesis was to determine the potential impact of heat stress (HS) on physiological traits of lactating cows and semen quality of bulls kept in a temperate climate. The thesis is comprised of three studies. An innovative statistical modeling aspect common to all three studies was the application of random regression methodology (RRM) to study the phenotypic and genetic trajectory of traits in dependency of a continuous temperature humidity index (THI). In the first study, semen quality and quantity traits of 562 Holstein sires kept on an AI station in northwestern Germany were analyzed in the course of THI calculated from data obtained from the nearest weather station. Heat stress was identified based on a decline in semen quality and quantity parameters. The identified general HS threshold (THI = 60) and the thermoneutal zone (THI in the range from 50 to 60) for semen production were lower than detected in studies conducted in tropical and subtropical climates. Even though adult bulls were characterized by higher semen productivity compared to younger bulls, they responded with a stronger semen production loss during harsh environments. Heritabilities (low to moderate range) and additive genetic variances of semen characteristics varied with different levels of THI. Also, based on genetic correlations genotype, by environment interactions were detected. Taken together, these findings suggest the application of specific selection strategies for specific climate conditions. In the second study, the effect of the continuous environmental descriptor THI as measured inside the barns on rectal temperatures (RT), skin temperatures (ST), vaginal temperatures (VT), respiration rates (RR), and pulse rate (PR) of lactating Holstein Friesian (HF) and dual-purpose German black pied cattle (DSN) was analyzed. Increasing HS from THI 65 (threshold) to THI 86 (maximal THI) resulted in an increase of RT by 0.6 °C (DSN) and 1 °C (HF), ST by 3.5 °C (HF) and 8 °C (DSN), VT by 0.3 °C (DSN), and RR by 47 breaths / minute (DSN), and decreased PR by 7 beats / minute (DSN). The undesired effects of rising THI on physiological traits were most pronounced for cows with high levels of milk yield and milk constituents, cows in early days in milk and later parities, and during summer seasons in the year 2014. In the third study of this dissertation, the genetic components of the cow’s physiological responses to HS were investigated. Heat stress was deduced from indoor THI measurements, and physiological traits were recorded on native DSN cows and their genetically upgraded crosses with Holstein Friesian sires in two experimental herds from pasture-based production systems reflecting a harsh environment of the northern part of Germany. Although heritabilities were in a low range (from 0.018 to 0.072), alterations of heritabilities, repeatabilities, and genetic components in the course of THI justify the implementation of genetic evaluations including heat stress components. However, low repeatabilities indicate the necessity of using repeated records for measuring physiological traits in German cattle. Moderate EBV correlations between different trait combinations indicate the potential of selection for one trait to simultaneously improve the other physiological attributes. In conclusion, bulls of AI centers and lactating cows suffer from HS during more extreme weather conditions also in the temperate climate of Northern Germany. Monitoring physiological traits during warm and humid conditions could provide precious information for detection of appropriate times for implementation of cooling systems and changes in feeding and management strategies. Subsequently, the inclusion of these physiological traits with THI specific breeding values into overall breeding goals could contribute to improving cattle adaptability by selecting the optimal animal for extreme hot and humid conditions. Furthermore, the recording of meteorological data in close distance to the cow and visualizing the surface body temperature by infrared thermography techniques might be helpful for recognizing heat tolerance and adaptability in cattle.

A Survey of the Relationship between Climatic Heat Stress Indices and Fundamental Milk Components Considering Uncertainty

The main purpose of this study is to assess the relationship between four bioclimatic indices for cattle (environmental stress, heat load, modified heat load, and respiratory rate predictor indices) and three main milk components (fat, protein, and milk yield) considering uncertainty. The climate parameters used to calculate the climate indices were taken from the NASA-Modern Era Retrospective-Analysis for Research and Applications (NASA-MERRA) reanalysis from 2002 to 2010. Cow milk data were considered for the same period from April to September when the cows use the natural pasture. The study is based on a linear regression analysis using correlations as a summarizing diagnostic. Bootstrapping is used to represent uncertainty information in the confidence intervals. The main results identify an interesting relationship between the milk compounds and climate indices under all climate conditions. During spring, there are reasonably high correlations between the fat and protein concentrations vs. the climate indices, whereas there are insignificant dependencies between the milk yield and climate indices. During summer, the correlation between the fat and protein concentrations with the climate indices decreased in comparison with the spring results, whereas the correlation for the milk yield increased. This methodology is suggested for studies investigating the impacts of climate variability/change on food and agriculture using short term data considering uncertainty.

Growth and yield of groundnut, sesame and roselle in an Acacia senegal agroforestry system in North Kordofan, Sudan

A field experiment was conducted under rainfed conditions in western Sudan at El-Obeid Research Farm and Eldemokeya Forest Reserve, North Kordofan State, during the growing seasons 2004/05 and 2005/06. The main objective was to investigate the soil physical and chemical properties and yield of groundnut (Arachis hypogea), sesame (Sesamum indicum) and roselle (Hibiscus sabdariffa) of an Acacia senegal agroforestry system in comparison with the sole cropping system. Data were recorded for soil physical and chemical properties, soil moisture content, number of pods per plant, fresh weight (kg ha^−1) and crop yield (kg ha^−1). The treatments were arranged in Randomized Complete Block Design (RCBD) and replicated four times. Significant differences (P < 0.05) were obtained for sand and silt content on both sites, while clay content was not significantly different on both sites. The nitrogen (N) and organic carbon were significantly (P < 0.05) higher in the intercropping system in Eldemokeya Forest Reserve compared with sole cropping. Soil organic carbon, N and pH were not significant on El-Obeid site. Yet the level of organic carbon, N, P and pH was higher in the intercropping system. Fresh weight was significantly different on both sites. The highest fresh weight was found in the intercropping system. Dry weights were significantly different for sesame and roselle on both sites, while groundnut was not significantly different. On both sites intercropping systems reduced groundnut, sesame and roselle yields by 26.3, 12 and 20.2%, respectively. The reduction in yield in intercropping plots could be attributed to high tree density, which resulted in water and light competition between trees and the associated crops.

Ermittlung geeigneter Methoden zur Differenzierung und Qualitätsbeurteilung unterschiedlicher Milchqualitäten aus verschiedenen on-farm-Experimenten

Zusammenfassung: Ziel der Arbeit war ein Methodenvergleich zur Beurteilung der Milchqualität unterschiedlicher Herkünfte. Am Beispiel von Milchproben aus unterschiedlicher Fütterung sowie an Milchproben von enthornten bzw. horntragenden Kühen wurde geprüft, welche der angewendeten Methoden geeignet ist, die Vergleichsproben zu unterscheiden (Differenzierungsfähigkeit der Methoden) und inwieweit eine Qualitätsbeurteilung möglich ist (hinsichtlich Milchleistung, Fett-, Eiweiß-, Lactose- (=F,E,L), Harnstoff-gehalt und Zellzahl (=SCC), Säuerungseigenschaften (=SE), Fettsäuremuster (=FS-Muster), Protein- und Metabolit-Zusammensetzung (=Pr&M), Fluoreszenz-Anregungs-Spektroskopie-Eigenschaften (=FAS) und Steigbild-Merkmalen). Zusätzlich wurde vorab die Steigbildmethode (=SB-M) für das Produkt Rohmilch standardisiert und charakterisiert, um die Reproduzierbarkei der Ergebnisse sicherzustellen. Die Untersuchungen zur SB-M zeigten, dass es Faktoren gibt, die einen deutlichen Einfluß auf die Bildmerkmals-Ausprägung aufweisen. Dazu gehören laborseitig die Klimabedingungen in der Kammer, die Verdünnungsstufe der Probe, die Standzeiten der Vorverdünnung (Reaktionen mit der Luft, Alterung usw.), und tagesspezifisch auftretende Effekte, deren Ursache unbekannt ist. Probenseitig sind sehr starke tierindividuelle Effekte auf die Bildmerkmals-Ausprägung festzustellen, die unabhängig von Fütterung, Alter, Laktationsstadium und Genetik auftreten, aber auch Fütterungsbedingungen der Kühe lassen sich in der Bildmerkmals-Ausprägung wiederfinden. Die Art der Bildauswertung und die dabei berücksichtigten Bildmerkmale ist von großer Bedeutung für das Ergebnis. Die im Rahmen dieser Arbeit untersuchten 46 Probenpaare (aus den Fütterungsvergleichen (=FV) und zur Thematik der Hörner) konnten in 91% der Fälle korrekt gruppiert werden. Die Unterschiede konnten benannt werden. Drei FV wurden auf drei biologisch-dynamischen Höfen unter Praxis-Bedingungen durchgeführt (on-farm-Experimente). Es wurden jeweils zwei vergleichbare Gruppen à mindestens 11 Kühen gebildet, die im Cross-Over-Design gefüttert wurden, mit Probennahme am 14. und 21. Tag je Periode. Es wurden folgende FV untersucht: A: Wiesenheu vs. Kleegrasheu (=KG-Heu), B: Futterrüben (=FuR) vs. Weizen (Ergänzung zu Luzernegrasheu ad lib.), C: Grassilage vs. Grasheu. Bei Versuch A sind die Futtereffekte am deutlichsten, Gruppeneffekte sind gering. Die Milch der Wiesenheu-Variante hat weniger CLA’s und n3- FS und mehr mittellangkettige FS (MCT-FS), das Pr&M-Muster weist auf „Gewebereifung und Ausdifferenzierung“ vs. bei KG-Heu „Nährstoff-fülle, Wachstum und Substanz-Einlagerung und die SB zeigen fein ausdifferenzierte Bildmerkmale. Bei Versuch B sind die Futtereffekte ähnlich groß wie die Gruppeneffekte. Bei vergleichbarer Milchleistung weist die Milch der FuR-Variante höhere F- und E-Gehalte auf, sie säuert schneller und mehr, das FS-Muster weist auf eine „intensive“ Fütterung mit vermehrt MCT- FS, und die Pr&M-Untersuchungen charakterisieren sie mit „Eisentransport und Fetttröpfchenbildung“ vs. bei Weizen „mehr Abwehr-, Regulations- und Transportfunktion“ /. „mehr Lipidsynthese“. Die SB charakterisieren mit „große, kräftige Formen, verwaschen“ vs. „kleine, ausdifferenzierte Bildmerkmal“ für FuR vs. Weizen. Die FAS charakterisiert sie mit „Saftfutter-typisch“ vs. „Samentypisch“. Versuch C weist die geringsten Futtereffekt auf, und deutliche Gruppen- und Zeiteffekte. Milchleistung und F,E,L-Gehalte zeigen keinen Futtereffekt. Die Milch der Heu-Variante säuert schneller, und sie weist mehr SCT und MCT- FS auf. Pr&M-Untersuchungen wurden nicht durchgeführt. Die SB charakterisieren bei Heumilch mit „fein, zart, durchgestaltet, hell“, bei Silagemilch mit „kräftig, wäßrig-verwaschen, dunkler“. Die FAS kann keine konsistenten Unterschiede ermitteln. Der Horn-Einfluß auf die Milchprobe wurde an 34 Probenpaaren untersucht. Von 11 Höfen wurden je zwei möglichst vergleichbare Gruppen zusammengestellt, die sich nur im Faktor „Horn“ unterscheiden, und im wöchentlichen Abstand drei mal beprobt. F,E,L, SCC und SE der Proben sowie die FAS-Messungen weisen keine konsistenten signifikanten Unterschiede zwischen den Horn-Varianten auf. Pr&M weisen bei den untersuchten Proben (von zwei Höfen) auf Horneffekte hin: bei Eh eine Erhöhung von Immun-Abwehr-Funktionen, sowie einer Abnahme phosphorylierter C3- und C6-Metabolite und Beta-Lactoglobulin. Mit den SB ließen sich für die gewählten Merkmale (S-Größe und g.B.-Intensität) keine Horneffekte feststellen. FS, Pr&M-Muster sowie Harnstoffgehalt und SB (und z.T. Milchleistung) zeigten je FV ähnliche Effekt-Intensitäten für Futter-, Gruppen- und Zeiteffekte, und konnten die Cross-Over-Effekte gut wiedergeben. F- und E-Gehalte konnten neben tierindividuellen Effekten nur in FV B auch Futtereffekte aufzeigen. In FV C zeigten die SE der Proben den deutlichsten Futtereffekt, die anderen Methoden zeigten hier vorrangig Gruppen-Effekte, gefolgt von Futter- und Zeiteffekten. Die FAS zeigte den SB vergleichbare Ergebnisse, jedoch weniger sensibel reagierend. Die Interpretation von Qualitätsaspekten war bei konsistent differenzierbaren Proben (FV A, B, C) am fundiertesten mit Hilfe der FS möglich, da über die Synthese von FS und beeinflussende Faktoren schon vielfältige Erkenntnisse vorliegen. Das Pr&M-Muster war nach einer weiteren Methodenentwicklung bei der Deutung von Stoffwechselprozessen sehr hilfreich. Die FAS konnte z.T. eine zu der Fütterungsvariante passende Charakterisierung liefern. Für die SB-M fehlt es noch an Referenzmaterial, um Angaben zu Qualitätsaspekten zu machen, wenngleich Probenunterschiede aufgezeigt und Proben-Eigenschaften charakterisiert werden konnten.

Biochar improves fertility of a clay soil in the Brazilian Savannah: short term effects and impact on rice yield

The objective of this study was to report single season effects of wood biochar (char) application coupled with N fertilization on soil chemical properties, aerobic rice growth and grain yield in a clayey Rhodic Ferralsol in the Brazilian Savannah. Char application effected an increase in soil pH, K, Ca, Mg, CEC, Mn and nitrate while decreasing Al content and potential acidity of soils. No distinct effect of char application on grain yield of aerobic rice was observed. We believe that soil properties impacted by char application were inconsequential for rice yields because neither water, low pH, nor the availability of K or P were limiting factors for rice production. Rate of char above 16 Mg ha^(−1) reduced leaf area index and total shoot dry matter by 72 days after sowing. The number of panicles infected by rice blast decreased with increasing char rate. Increased dry matter beyond the remobilization capacity of the crop, and high number of panicles infected by rice blast were the likely cause of the lower grain yield observed when more than 60 kg N ha^(−1) was applied. The optimal rate of N was 46 kg ha^(−1) and resulted in a rice grain yield above 3 Mg ha^(−1).

Opportunities and constraints of peri-urban buffalo and dairy cattle systems in Faisalabad, Punjab, Pakistan

In the big cities of Pakistan, peri-urban dairy production plays an important role for household income generation and the supply of milk and meat to the urban population. On the other hand, milk production in general, and peri-urban dairy production in particular, faces numerous problems that have been well known for decades. Peri-urban dairy producers have been especially neglected by politicians as well as non-government-organizations (NGOs). Against this background, a study in Pakistan’s third largest city, Faisalabad (Punjab Province), was carried out with the aims of gathering basic information, determining major constraints and identifying options for improvements of the peri-urban milk production systems. For data collection, 145 peri-urban households (HH) engaged in dairy production were interviewed face to face using a structured and pretested questionnaire with an interpreter. For analyses, HH were classified into three wealth groups according to their own perception. Thus, 38 HH were poor, 95 HH well off and 12 HH rich (26.2%, 65.5% and 8.3%, respectively). The richer the respondents perceived their HH, the more frequently they were actually in possession of high value HH assets like phones, bank accounts, motorbikes, tractors and cars. Although there was no difference between the wealth groups with respect to the number of HH members (about 10, range: 1 to 23), the educational level of the HH heads differed significantly: on average, heads of poor HH had followed education for 3 years, compared to 6 years for well off HH and 8 years for rich HH. About 40% of the poor and well off HH also had off-farm incomes, while the percentage was much higher - two thirds (67%) - for the rich HH. The majority of the HH were landless (62%); the rest (55 HH) possessed agricultural land from 0.1 to 10.1 ha (average 2.8 ha), where they were growing green fodder: maize, sorghum and pearl millet in summer; berseem, sugar cane and wheat were grown in winter. Dairy animals accounted for about 60% of the herds; the number of dairy animals per HH ranged from 2 to 50 buffaloes (Nili-Ravi breed) and from 0 to 20 cows (mostly crossbred, also Sahiwal). About 37% (n=54) of the HH did not keep cattle. About three quarters of the dairy animals were lactating. The majority of the people taking care of the animals were family workers; 17.3% were hired labourers (exclusively male), employed by 11 rich and 32 well off HH; none of the poor HH employed workers, but the percentages were 33.7% for the well off and 91.7% for the rich HH. The total number of workers increased significantly with increasing wealth (poor: 2.0; well off:2.5; rich: 3.4). Overall, 69 female labourers were recorded, making up 16.8% of employed workers and one fourth of the HH’s own labourers. Apparently, their only duty was to clean the animals´ living areas; only one of them was also watering and showering the animals. Poor HH relied more on female workers than the other two groups: 27.1% of the workers of poor HH were women, but only 14.8% and 6.8% of the labour force of well off and rich HH were female. Two thirds (70%) of the HH sold milk to dhodis (middlemen) and one third (35%) to neighbours; three HH (2%) did doorstep delivery and one HH (1%) had its own shop. The 91 HH keeping both species usually sold mixed milk (97%). Clients for mixed and pure buffalo milk were dhodis (78%, respectively 59%) and neighbours (28%, respectively 47%). The highest milk prices per liter (Pakistani Rupees, 100 PKR @ 0.8 Euro) were paid by alternative clients (44 PKR; 4 HH), followed by neighbours (40 PKR, 50 HH); dhodis paid lower prices (36 PKR, 99 HH). Prices for pure buffalo and mixed milk did not differ significantly. However, HH obtaining the maximum price from the respective clients for the respective type of milk got between 20% (mixed milk, alternative clients) and 68% (mixed milk, dhodi) more than HH fetching the minimum price. Some HH (19%) reported 7% higher prices for the current summer than the preceding winter. Amount of milk sold and distance from the HH to the city center did not influence milk prices. Respondents usually named problems that directly affected their income and that were directly and constantly visible to them, such as high costs, little space and fodder shortages. Other constraints that are only influencing their income indirectly, e.g. the relatively low genetic potential of their animals due to neglected breeding as well as the short- and long-term health problems correlated with imbalanced feeding and insufficient health care, were rarely named. The same accounts for problems accompanying improper dung management (storage, disposal, burning instead of recycling) for the environment and human health. Most of the named problems are linked to each other and should be addressed within the context of the entire system. Therefore, further research should focus on systematic investigations and improvement options, taking a holistic and interdisciplinary approach instead of only working in single fields. Concerted efforts of dairy farmers, researchers, NGOs and political decision makers are necessary to create an economic, ecological and social framework that allows dairy production to serve the entire society. For this, different improvement options should be tested in terms of their impact on environment and income of the farmers, as well as feasibility and sustainability in the peri-urban zones of Faisalabad.

Intrinsic channel closing in strong-field single ionization of H2

Die Ionisation von H2 in intensiven Laserpulsen wird mit Hilfe der numerischen Integration der zeitabhängigen Schrödingergleichung für ein Einelektronenmodell untersucht, das die Vibrationsbewegung berücksichtigt. Die Spektren der kinetischen Elektronenenergie hängen stark von der Vibrationsquantenzahl des erzeugten H2+ Ions ab. Für bestimmte Vibrationszustände ist die Ausbeute der Elektronen in der Mitte des Plateaus stark erhöht. Der Effekt wird "channel closings" zugeschrieben, die in Atomen durch Variation der Laserintensität beobachtet wurden. The ionization of H2 in intense laser pulses is studied by numerical integration of the time-dependent Schrödinger equation for a single-active-electron model including the vibrational motion. The electron kinetic energy spectra in high-order above-threshold ionization are strongly dependent on the vibrational quantum number of the created H2+ ion. For certain vibrational states, the electron yield in the mid-plateau region is strongly enhanced. The effect is attributed to channel closings, which were previously observed in atoms by varying the laser intensity.

Management approaches in organic potato and tomato production

The presented thesis considered three different system approach topics to ensure yield and plant health in organically grown potatoes and tomatoes. The first topic describes interactions between late blight (Phytophthora infestans) incidence and soil nitrogen supply on yield in organic potato farming focussing in detail on the yield loss relationship of late blight based on results of several field trials. The interactive effects of soil N-supply, climatic conditions and late blight on the yield were studied in the presence and absence of copper fungicides from 2002-2004 for the potato cultivar Nicola. Under conditions of central Germany the use of copper significantly reduced late blight in almost all cases (15-30 %). However, the reductions in disease through copper application did not result in statistically significant yield increases (+0 – +10 %). Subsequently, only 30 % of the variation in yield could be attributed to disease reductions. A multiple regression model (R²Max), however, including disease reduction, growth duration and temperature sum from planting until 60 % disease severity was reached and soil mineral N contents 10 days after emergence could explain 75 % of the observed variations in yield. The second topic describes the effect of some selected organic fertilisers and biostimulant products on nitrogen-mineralization and efficiency, yield and diseases in organic potato and tomato trials. The organic fertilisers Biofeed Basis (BFB, plant derived, AgroBioProducts, Wageningen, Netherlands) and BioIlsa 12,5 Export (physically hydrolysed leather shavings, hair and skin of animals; ILSA, Arizignano, Italy) and two biostimulant products BioFeed Quality (BFQ, multi-compound seaweed extract, AgroBioProducts) and AUSMA (aqueous pine and spruce needle extract, A/S BIOLAT, Latvia), were tested. Both fertilisers supplied considerable amounts of nitrogen during the main uptake phases of the crops and reached yields as high or higher as compared to the control with horn meal fertilisation. The N-efficiency of the tested fertilisers in potatoes ranged from 90 to 159 kg yield*kg-1 N – input. Most effective with tomatoes were the combined treatments of fertiliser BFB and the biostimulants AUSMA and BFQ. Both biostimulants significantly increased the share of healthy fruit and/or the number of fruits. BFQ significantly increased potato yields (+6 %) in one out of two years and reduced R. solani-infestation in the potatoes. This suggests that the biostimulants had effects on plant metabolism and resistance properties. However, no effects of biostimulants on potato late blight could be observed in the fields. The third topic focused on the effect of suppressive composts and seed tuber health on the saprophytic pathogen Rhizoctonia solani in organic potato systems. In the present study 5t ha-1 DM of a yard and bio-waste (60/40) compost produced in a 5 month composting process and a 15 month old 100 % yard waste compost were used to assess the effects on potato infection with R. solani when applying composts within the limits allowed. Across the differences in initial seed tuber infestation and 12 cultivars 5t DM ha-1 of high quality composts, applied in the seed tuber area, reduced the infestation of harvested potatoes with black scurf, tuber malformations and dry core tubers by 20 to 84 %, 20 to 49 % and 38 to 54 %, respectively, while marketable yields were increased by 5 to 25 % due to lower rates of wastes after sorting (marketable yield is gross yield minus malformed tubers, tubers with dry core, tubers with black scurf > 15% infested skin). The rate of initial black scurf infection of the seed tubers also affected tuber number, health and quality significantly. Compared to healthy seed tubers initial black scurf sclerotia infestation of 2-5 and >10 % of tuber surface led in untreated plots to a decrease in marketable yields by 14-19 and 44-66 %, a increase of black scurf severity by 8-40 and 34-86 % and also increased the amount of malformed and dry core tubers by 32-57 and 109-214 %.

Determination of yield and quality parameters of energy crops applying laboratory and field spectroscopy

A real-time analysis of renewable energy sources, such as arable crops, is of great importance with regard to an optimised process management, since aspects of ecology and biodiversity are considered in crop production in order to provide a sustainable energy supply by biomass. This study was undertaken to explore the potential of spectroscopic measurement procedures for the prediction of potassium (K), chloride (Cl), and phosphate (P), of dry matter (DM) yield, metabolisable energy (ME), ash and crude fibre contents (ash, CF), crude lipid (EE), nitrate free extracts (NfE) as well as of crude protein (CP) and nitrogen (N), respectively in pretreated samples and undisturbed crops. Three experiments were conducted, one in a laboratory using near infrared reflectance spectroscopy (NIRS) and two field spectroscopic experiments. Laboratory NIRS measurements were conducted to evaluate to what extent a prediction of quality parameters is possible examining press cakes characterised by a wide heterogeneity of their parent material. 210 samples were analysed subsequent to a mechanical dehydration using a screw press. Press cakes serve as solid fuel for thermal conversion. Field spectroscopic measurements were carried out with regard to further technical development using different field grown crops. A one year lasting experiment over a binary mixture of grass and red clover examined the impact of different degrees of sky cover on prediction accuracies of distinct plant parameters. Furthermore, an artificial light source was used in order to evaluate to what extent such a light source is able to minimise cloud effects on prediction accuracies. A three years lasting experiment with maize was conducted in order to evaluate the potential of off-nadir measurements inside a canopy to predict different quality parameters in total biomass and DM yield using one sensor for a potential on-the-go application. This approach implements a measurement of the plants in 50 cm segments, since a sensor adjusted sideways is not able to record the entire plant height. Calibration results obtained by nadir top-of-canopy reflectance measurements were compared to calibration results obtained by off-nadir measurements. Results of all experiments approve the applicability of spectroscopic measurements for the prediction of distinct biophysical and biochemical parameters in the laboratory and under field conditions, respectively. The estimation of parameters could be conducted to a great extent with high accuracy. An enhanced basis of calibration for the laboratory study and the first field experiment (grass/clover-mixture) yields in improved robustness of calibration models and allows for an extended application of spectroscopic measurement techniques, even under varying conditions. Furthermore, off-nadir measurements inside a canopy yield in higher prediction accuracies, particularly for crops characterised by distinct height increment as observed for maize.