Nutrient supply to dairy cows from processed white lupines

Abstract

The objective of this study was to compare the DVE/OEB system (DVE = truly absorbed protein in the small intestine; OEB = degraded protein balance (DPB) in Dutch) and the NRC-2001 model in the prediction of supply of protein to dairy cows from processed white lupines (Lupinus albus L.). Comparisons were made in terms of (1) ruminally synthesized microbial CP, (2) truly absorbed protein in the small intestine, and (3) degraded protein balance. In addition, the systematic investigation of roasting of the white lupines at various temperatures (110, 130, or 150°C) and times (15, 30 or 45 min) on manipulation of digestive behaviour and the potential nutrient supply to dairy cows were also carried out, to obtain information on best processing conditions as intestinal protein sources (to achieve target values for potential high net absorbable protein in the small intestine while holding any N loss in the rumen to a low level). The results showed that the predicted values from the DVE/OEB system and the NRC-2001 model had significant correlations with high R ( > 0.83) values. However, using the DVE/OEB system, the overall average microbial protein supply based on available energy was 11% higher and the truly absorbed protein in the small intestine was 7% higher than that predicted by the NRC-2001 model. The difference was also found in the prediction of the degraded protein balances (DPB), which was 8% higher based on data from the NRC-2001 model. These differences are due to considerably different factors used in calculations in the two models, although both are based on similar principles. This indicates that a further refinement is needed for a modern protein evaluation and prediction system. In addition, this study showed that the roasting at higher temperature and time was effective in shifting protein degradation from rumen to intestines and it increased the DVE or MP values without reaching the negative degraded protein balance. The processing at 150°C for 30 or 45 min might be the best treatments for white lupine due to its higher DVE and MP values and the very low DPB values.

Keywords:

• Lupinus albus
• Feed evaluation
• Heat treatment
• NRC-2001 dairy model
• DVE/OEB system
• Dairy cows

Notes

Abbreviations

A Soluble fraction [%] which is assumed to be degraded rapidly and completely; AECP Truly absorbed endogenous protein in the small intestine [g/kg DM] (NRC); AMCP^DVE Truly absorbed rumen synthesized microbial protein in the small intestine [g/kg DM] (DVE/OEB); AMCP^NRC Truly absorbed rumen synthesized microbial protein in the small intestine [g/kg DM] (NRC); ARUP^DVE Truly absorbed bypass feed protein in the small intestine [g/kg DM] (DVE/OEB); ARUP^NRC Truly absorbed rumen undegraded feed protein in the small intestine [g/kg DM] (NRC); B Insoluble but potentially degradable fraction [%]; C Undegradable fraction [%]; dAsh Digestibility of ash [%]; DOM Digested organic matter [g/kg DM]; dOM Digestibility of organic matter [%]; dRUP Digestibility of rumen undegradable protein in the small intestine [%]; DPB^OEB Degraded protein balance [g/kg DM] reflects the difference between the potential microbial protein synthesis based on rumen degraded feed CP and that based on energy (rumen fermented OM) available for microbial fermentation in the rumen, calculated as: MCP_RDP ^DVE – MCP_FOM (DVE/OEB); DPB^NRC Based on the data from NRC 2001 model, the degraded protein balance [g/kg DM] reflects the difference between the potential microbial protein synthesis based on ruminally degraded feed CP and that based on energy – TDN available for microbial fermentation in the rumen, calculated as: RDP^NRC – 1.18MCP_TDN; DVE Truly absorbed protein in the small intestine [g/kg DM], contributed by (1) feed protein escaping rumen degradation (RUP^DVE), (2) microbial protein synthesized in the rumen (MCP_FOM), and (3) a correction for endogenous protein losses in the digestive tract (ENDP) (DVE/OEB); ECP Rumen endogenous crude protein [g/kg DM] (NRC); ENDP Endogenous protein losses in the digestive tract [g/kg DM] (DVE/OEB); FOM Organic matter fermented in the rumen [g/kg DM]; Kd The rate of degradation of the B fraction [%/h]; Kp The rate of passage [%/h]; MCP_FOM Microbial protein synthesized in the rumen based on available energy [g/kg DM] (DVE/OEB); MCP^NRC Ruminally synthesized microbial CP [g/kg DM], calculated as 0.130 TDN, when RDP^NRC exceeds 1.18 TDN-predicted MCP (MCP_TDN). When RDP^NRC is less than 1.18 TDN-predicted MCP (MCP_TDN), then MCP is calculated as 0.85 of RDP^NRC (MCP_RDP) (NRC); MCP_RDP ^DVE Microbial protein synthesized in the rumen based on rumen degraded feed crude protein, calculated as: CP·(1 – 1.11%RUP/100) [g/kg DM] (DVE/OEB); MCP_RDP ^NRC Microbial protein synthesized in the rumen based on available protein, calculated as 0.85 of RDP^NRC [g/kg DM] (NRC); MCP_TDN Microbial protein synthesized in the rumen based on available energy (discounted TDN) [g/kg DM] (NRC); MP Metabolizable protein [g/kg DM] (defined as the true protein that is digested postruminally and the component amino acid absorbed by the intestine) contributed by (1) ruminally undegraded feed CP, (2) ruminally synthesized microbial CP, and (3) endogenous CP (NRC); %RUDM Ruminally undegraded feed DM fraction [%]; RDP^DVE Ruminally degraded feed CP, calculated according the formula in DVE/OEB system [g/kg DM]; RDP^NRC Ruminally degraded feed CP, calculated according the formula in NRC-2001 dairy model [g/kg DM]; %RUP Ruminally undegraded feed CP fraction [%]; RUP^DVE Ruminally undegraded feed CP, calculated according the formula in DVE/OEB system [g/kg DM]; RUP^NRC Ruminally undegraded feed CP, calculated according the formula in NRC-2001 dairy model [g/kg DM]; T0 Lag time [h] in which no degradation of B takes place; TDN_1X Total digestible nutrient; TPSI True protein supplied to the small intestine [g/kg DM]; UAsh Undigested ash [g/kg DM]; UDM Undigested dry matter [g/kg DM]; UOM Undigested organic matter [g/kg DM]

Additional information

Notes on contributors

P Yu

Abbreviations A Soluble fraction [%] which is assumed to be degraded rapidly and completely; AECP Truly absorbed endogenous protein in the small intestine [g/kg DM] (NRC); AMCPDVE Truly absorbed rumen synthesized microbial protein in the small intestine [g/kg DM] (DVE/OEB); AMCPNRC Truly absorbed rumen synthesized microbial protein in the small intestine [g/kg DM] (NRC); ARUPDVE Truly absorbed bypass feed protein in the small intestine [g/kg DM] (DVE/OEB); ARUPNRC Truly absorbed rumen undegraded feed protein in the small intestine [g/kg DM] (NRC); B Insoluble but potentially degradable fraction [%]; C Undegradable fraction [%]; dAsh Digestibility of ash [%]; DOM Digested organic matter [g/kg DM]; dOM Digestibility of organic matter [%]; dRUP Digestibility of rumen undegradable protein in the small intestine [%]; DPBOEB Degraded protein balance [g/kg DM] reflects the difference between the potential microbial protein synthesis based on rumen degraded feed CP and that based on energy (rumen fermented OM) available for microbial fermentation in the rumen, calculated as: MCPRDP DVE – MCPFOM (DVE/OEB); DPBNRC Based on the data from NRC 2001 model, the degraded protein balance [g/kg DM] reflects the difference between the potential microbial protein synthesis based on ruminally degraded feed CP and that based on energy – TDN available for microbial fermentation in the rumen, calculated as: RDPNRC – 1.18MCPTDN; DVE Truly absorbed protein in the small intestine [g/kg DM], contributed by (1) feed protein escaping rumen degradation (RUPDVE), (2) microbial protein synthesized in the rumen (MCPFOM), and (3) a correction for endogenous protein losses in the digestive tract (ENDP) (DVE/OEB); ECP Rumen endogenous crude protein [g/kg DM] (NRC); ENDP Endogenous protein losses in the digestive tract [g/kg DM] (DVE/OEB); FOM Organic matter fermented in the rumen [g/kg DM]; Kd The rate of degradation of the B fraction [%/h]; Kp The rate of passage [%/h]; MCPFOM Microbial protein synthesized in the rumen based on available energy [g/kg DM] (DVE/OEB); MCPNRC Ruminally synthesized microbial CP [g/kg DM], calculated as 0.130 TDN, when RDPNRC exceeds 1.18 TDN-predicted MCP (MCPTDN). When RDPNRC is less than 1.18 TDN-predicted MCP (MCPTDN), then MCP is calculated as 0.85 of RDPNRC (MCPRDP) (NRC); MCPRDP DVE Microbial protein synthesized in the rumen based on rumen degraded feed crude protein, calculated as: CP·(1 – 1.11%RUP/100) [g/kg DM] (DVE/OEB); MCPRDP NRC Microbial protein synthesized in the rumen based on available protein, calculated as 0.85 of RDPNRC [g/kg DM] (NRC); MCPTDN Microbial protein synthesized in the rumen based on available energy (discounted TDN) [g/kg DM] (NRC); MP Metabolizable protein [g/kg DM] (defined as the true protein that is digested postruminally and the component amino acid absorbed by the intestine) contributed by (1) ruminally undegraded feed CP, (2) ruminally synthesized microbial CP, and (3) endogenous CP (NRC); %RUDM Ruminally undegraded feed DM fraction [%]; RDPDVE Ruminally degraded feed CP, calculated according the formula in DVE/OEB system [g/kg DM]; RDPNRC Ruminally degraded feed CP, calculated according the formula in NRC-2001 dairy model [g/kg DM]; %RUP Ruminally undegraded feed CP fraction [%]; RUPDVE Ruminally undegraded feed CP, calculated according the formula in DVE/OEB system [g/kg DM]; RUPNRC Ruminally undegraded feed CP, calculated according the formula in NRC-2001 dairy model [g/kg DM]; T0 Lag time [h] in which no degradation of B takes place; TDN1X Total digestible nutrient; TPSI True protein supplied to the small intestine [g/kg DM]; UAsh Undigested ash [g/kg DM]; UDM Undigested dry matter [g/kg DM]; UOM Undigested organic matter [g/kg DM]