Nitrogen efficiency of dairy cattle : from protein evaluation to ammonia emission

Diet optimization contributes considerably to increased nitrogen efficiency of dairy cattle, resulting in reduced nitrogen losses. This thesis focuses on three themes: the potential advances in protein evaluation systems for ruminants, the relationship between dairy cow diet and ammonia emission and the opportunities to monitor ammonia emission from dairy cow barns by application of milk urea content as a practical indicator. Overall, the present work shows that farm management can be aimed at increased nitrogen efficiency of dairy cattle and reduced ammonia emission without compromising other sustainability objectives such as the integral ecological footprint, animal health and farm profitability. </p

Evaluation of an application for dynamic feeding of dairy cows

Dynamic feeding is an innovative application for concentrate feeding of dairy cows. Daily individual settings are derived from the actual individual milk yield response to concentrate intake. This response is estimated using an adaptive dynamic linear model. Optimal daily individual settings for concentrate supply are directed to achieve the maximum gross margin milk returns minus concentrate costs. This response curve plays a key role in the application. The response curve is derived from a mechanistic model for milk production and can also be established empirically from daily milk yield development during early lactation when concentrate supply increase is linear. A test application for dynamic feeding ran for several months in 2008 and results from 145 cows at one farm on 17 December 2008 have been used to demonstrate the variation in individual response. The gross margin, milk returns minus concentrate costs, varied from 2.52 to 26.32 €/day. The estimated response parameters provide insight in variation between individuals concerning the effects of concentrate and base ration intake on daily milk yield. Economical and nutritional aspects can be evaluated for each individual. Individual dynamic feeding towards an economic optimum indicates that excessive changes in individual bodyweighti can be prevented

Ammoniakemissie fors lager na voermaatregelen

De ammoniakemissie vanuit melkveestallen is aanzienlijk terug te dringen door de eiwitvoeding aan te scherpen. Via het melkureumgehalte is goed in beeld te brengen in welke mate de emissie afneemt

Sturing melkureumgehalte op dierniveau via de voeding

Het Praktijkonderzoek Veehouderij voerde in de winterseizoenen van 1997-1998 en 1998-1999 een viertal voederproeven uit die antwoord moesten geven op de vraag of er variatie bestaat in het optimale melkureumgehalte tussen individuele dieren en in welke mate het melkureumgehalte van individuele dieren valt te sturen door middel van de voeding

Modelling Animal Systems Paper: Update of the Dutch protein evaluation system for ruminants: the DVE/OEB2010 system

In the current Dutch protein evaluation system (the DVE/OEB1991 system), two characteristics are calculated for each feed: true protein digested in the intestine (DVE) and the rumen degradable protein balance (OEB). Of these, DVE represents the protein value of a feed, while OEB is the difference between the potential microbial protein synthesis (MPS) on the basis of available rumen degradable protein and that on the basis of available rumen degradable energy. DVE can be separated into three components: (i) feed crude protein undegraded in the rumen but digested in the small intestine, (ii) microbial true protein synthesized in the rumen and digested in the small intestine, and (iii) endogenous protein lost in the digestive processes. Based on new research findings, the DVE/OEB1991 system has recently been updated to the DVE/OEB2010 system. More detail and differentiation is included concerning the representation of chemical components in feed, the rumen degradation characteristics of these components, the efficiency of MPS and the fractional passage rates. For each chemical component, the soluble, washout, potentially degradable and truly non-degradable fractions are defined with separate fractional degradation rates. Similarly, fractional passage rates for each of these fractions were identified and partly expressed as a function of fractional degradation rate. Efficiency of MPS is related to the various fractions of the chemical components and their associated fractional passage rates. Only minor changes were made with respect to the amount of DVE required for maintenance and production purposes of the animal. Differences from other current protein evaluation systems, viz. the Cornell Net Carbohydrate and Protein system and the Feed into Milk system, are discussed

De Marke scherpt voerbenutting aan via mestscore

Deze zogenaamde 'mestscore' heeft inmiddels bijgedragen aan een verdere aanscherping van de voerbenutting

Changes in MEG resting-state networks are related to cognitive decline in type 1 diabetes mellitus patients

OBJECTIVE: Integrity of resting-state functional brain networks (RSNs) is important for proper cognitive functioning. In type 1 diabetes mellitus (T1DM) cognitive decrements are commonly observed, possibly due to alterations in RSNs, which may vary according to microvascular complication status. Thus, we tested the hypothesis that functional connectivity in RSNs differs according to clinical status and correlates with cognition in T1DM patients, using an unbiased approach with high spatio-temporal resolution functional network.; METHODS: Resting-state magnetoencephalographic (MEG) data for T1DM patients with (n=42) and without (n=41) microvascular complications and 33 healthy participants were recorded. MEG time-series at source level were reconstructed using a recently developed atlas-based beamformer. Functional connectivity within classical frequency bands, estimated by the phase lag index (PLI), was calculated within eight commonly found RSNs. Neuropsychological tests were used to assess cognitive performance, and the relation with RSNs was evaluated.; RESULTS: Significant differences in terms of RSN functional connectivity between the three groups were observed in the lower alpha band, in the default-mode (DMN), executive control (ECN) and sensorimotor (SMN) RSNs. T1DM patients with microvascular complications showed the weakest functional connectivity in these networks relative to the other groups. For DMN, functional connectivity was higher in patients without microangiopathy relative to controls (all p<0.05). General cognitive performance for both patient groups was worse compared with healthy controls. Lower DMN alpha band functional connectivity correlated with poorer general cognitive ability in patients with microvascular complications.; DISCUSSION: Altered RSN functional connectivity was found in T1DM patients depending on clinical status. Lower DMN functional connectivity was related to poorer cognitive functioning. These results indicate that functional connectivity may play a key role in T1DM-related cognitive dysfunction

Bedrijfsplan high-techbedrijf

Het high-techbedrijf heeft als doelstelling: Realisatie van een lage kostprjis per kg melk (75 cent) via een hoge productiviteit per ha en per manuur; bij een goede diergezondheid en dierwelzijn, waarbij voldaan wordt aan de eindnormen van Minas