Update of the Dutch protein evaluation system for ruminants: the DVE/OEB₂₀₁₀system

Abstract

SUMMARYIn the current Dutch protein evaluation system (the DVE/OEB1991system), 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/OEB1991system has recently been updated to the DVE/OEB2010system. 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.

Milk yield and milk composition responses to change in predicted net energy and metabolizable protein: a meta-analysis

“…In order to be able to predict responses, three key processes need to be quantified. First, the prediction of dry matter intake (DMI) response to dietary changes, second, rumen digestion and fermentation processes to obtain accurate estimates of nutrients available for absorption (Van Duinkerken et al, 2011;Volden, 2011;Sauvant and Nozière, 2016), and third, the partition of those absorbed nutrients between different life functions (Bauman, 2000;Friggens et al, 2013). One aspect of nutrient partitioning, the relation between changes in nutrient supply and milk production and composition, has received a lot of attention.…”

Passage kinetics of concentrates in dairy cows measured with carbon stable isotopes

“…Colucci et al, 1990;Lund et al, 2006;Ahvenjärvi et al, 2010) but effects of concentrate level in the diet on passage of feed are less clear. For instance, fractional passage of protein and starch in roughage and concentrates are fixed in the Dutch protein evaluation system for ruminants, whereas that for NDF is estimated from the fractional NDF degradation rate (Van Duinkerken et al, 2011). However, fractional passage rate of forages was found to increase with an increasing concentrate proportion in the diet (review of Offer and Dixon, 2000).…”

The energy and protein value of wheat, maize and blend DDGS for cattle and evaluation of prediction methods

“…For CP, also the soluble fraction in water (WSCP) was determined to calculate the fraction of small but insoluble particles (W-WSCP). The percentage of rumen bypass protein (RBP) was calculated according to Van Duinkerken et al (2011): In situ intestinal digestibility with cows The intestinal digestibility of RBP (dRBP) was determined with the mobile nylon bag technique using two cows provided with a T-cannula (R&K Techniek, Venlo, The Netherlands) in the upper part of the duodenum. First, rumen bypass material was collected by incubation of DDGS samples during 12 h (similar procedure as described above).…”

“…Calculation of the protein value The protein value was calculated according to the updated Dutch DVE/OEB system (Van Duinkerken et al, 2011). The true protein digested in the small intestine (DVE) was calculated as ARBP + AMP − ENDP with ARBP = truly absorbable bypass protein, AMP = truly absorbable microbial protein synthesized in the rumen and ENDP = endogenous protein excreted in the faeces.…”

“…Our RBP-values for maize and wheat DDGS are similar to those of Nuez-Ortín and Yu (2010), who obtained on average 66.1% and 54.4%, In our study intestinal digestibility of RBP was determined by incubating small nylon bags with residual material after 12 h of rumen incubation in the duodenum and collection of the bags in the faeces. This is considered as the reference method for determining dRBP in the Dutch protein system (Van Duinkerken et al, 2011). No other recent studies with DDGS were found where this in situ technique was used and mostly a three-step in vitro procedure with pepsin and pancreatin was applied (Mjoun et al, 2010;Nuez-Ortín and Yu, 2010;Li et al, 2012).…”