Hippenstiel, Friederike: Energy and nitrogen use efficiency in farm animal nutrition – opportunities and limitations for improvement. - Bonn, 2013. - Dissertation, Rheinische Friedrich-Wilhelms-Universität Bonn.
Online-Ausgabe in bonndoc: https://nbn-resolving.org/urn:nbn:de:hbz:5n-33190
@phdthesis{handle:20.500.11811/5553,
urn: https://nbn-resolving.org/urn:nbn:de:hbz:5n-33190,
author = {{Friederike Hippenstiel}},
title = {Energy and nitrogen use efficiency in farm animal nutrition – opportunities and limitations for improvement},
school = {Rheinische Friedrich-Wilhelms-Universität Bonn},
year = 2013,
month = sep,

note = {This thesis combines three different topics that are seemingly unconnected but inherently linked. The first part deals intensively with co-products from biofuel production on a European level. There are numerous co-products which are all suitable as protein supplements for ruminants, pigs and poultry. The results of a number of experiments with lactating dairy cows and fattening bulls suggest that distillers grains, rapeseed meal and rapeseed cake as the main protein source may support a high productive performance. Pigs would particularly benefit from breeding or production progress in further reduction of glucosinolate levels of rapeseed, whereas in cattle, a safer quality assessment of the rapeseed cake is needed. Another fundamental co-product of the biodiesel production is glycerine. In ruminant diets, glycerine at different purities may help to stabilise the hygienic quality of pelleted compound feeds without compromising physical quality of pellets. The efficient utilisation of biofuel co-products is a key tool towards more sustainable biofuel production. Future research should quantify all expenditures on the processing of biofuel co-products in order to be able to evaluate meaningful carbon footprints.
The second part of the thesis draws attention to the question of whether it makes sense to use equations based on feed and intake characteristics to estimate methane (CH4) emissions from dairy cows. Nine CH4 prediction equations were applied to five typical Central European diets in order to compare their applicability. As a result, smallest differences to mean values were observed with equations using neutral detergent fibre, while standard deviations were highest, and therefore showed the best capability to differentiate between diets, when using equations that operated with forage proportion and dry matter intake. The differences in levels of CH4 estimates show that the equations are still inaccurate and may only serve as implications to locate trends. It should be taken into consideration to expand datasets, involving future CH4 measurements, on animal and herd level, feeding typical up to date regional diets in order to get more precise equations, suitable for a greater range of estimations. To ease and simplify the future applications, the prediction equations could be classified into groups, clearly stating by which data they were derived, for example regional origin and diet composition.
In the third part of this study, 33 samples with main focus on unprotected or rumen-protected protein supplements, were analysed using an enzymatic in vitro procedure (EIVP) in order to determine intestinal crude protein (CP) digestibility (IPD) of ruminally undegraded CP (RUP). Results of this study showed that the EIVP seems to be an adequately working, simple and reliable method to estimate IPD of RUP in concentrate feeds. This method in its current, strictly standardized form can be applied to develop a database which can be used for protein evaluation systems for establishing tabular values of IPD. However, future studies may be constricted since sufficient reference values are missing.
In conclusion it can be stated that there is still research needed to improve existing systems in order to optimise feeding strategies to meet the animals’ nutrient requirements as well as minimising greenhouse gas (GHG) emissions and energy loss in agricultural production systems. This research should include the improvement of GHG estimation systems towards a more differentiated view to regional conditions and resources as well as an improvement of the protein evaluation system with standardised, easy to apply laboratory methods to estimate nutrient requirements for a more efficient usage of local resources and co-products.},

url = {http://hdl.handle.net/20.500.11811/5553}
}

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