PMID- 15644514
OWN - NLM
STAT- MEDLINE
DCOM- 20071026
LR  - 20170908
IS  - 1525-3163 (Electronic)
IS  - 0021-8812 (Linking)
VI  - 83
IP  - 2
DP  - 2005 Feb
TI  - Effect of carbohydrate source on ammonia utilization in lactating dairy cows.
PG  - 408-21
AB  - This study was conducted to investigate the effect of dextrose, starch, NDF, and 
      a carbohydrate (CHO) mix on utilization of ruminal ammonia in dairy cows. Four 
      ruminally and duodenally cannulated Holstein cows (BW = 788 +/- 31 kg; 217 +/- 35 
      d in milk) were allocated to four treatments in a 4 x 4 Latin square design 
      trial. Cows were fed an all alfalfa diet at 12-h intervals (DMI = 22.2 +/- 0.25 
      kg/d). Treatments were control, white oat fiber (NDF); corn dextrose (GLU); 
      cornstarch (STA); and a CHO mix (25% of each): apple pectin, GLU, STA, and NDF 
      (MIX). Carbohydrates were introduced intraruminally during feeding at 20% of 
      dietary DMI. Ruminal ammonia was labeled with (15)N. Ruminal pH was the highest 
      for NDF followed by STA and MIX and GLU (P < 0.001). Ruminal ammonia 
      concentration and pool size were decreased by GLU and STA compared with NDF (P < 
      0.001 and P = 0.03, respectively). Acetate, isobutyrate, isovalerate, and total 
      VFA concentration in the rumen were decreased (P = 0.009 to 0.001), and butyrate 
      was increased (P < 0.001) by GLU compared with the other CHO. Microbial N flow to 
      the duodenum was decreased (P < 0.05) by NDF compared with the other CHO, and the 
      flow of microbial N formed from ammonia was greater for STA compared with GLU and 
      NDF (P = 0.04 and 0.03, respectively). Urinary N loss was decreased (P = 0.05) by 
      GLU and STA, but overall (feces plus urine) N losses were not affected (P = 0.73) 
      by treatment. Milk urea concentration was lowered by GLU and STA compared with 
      NDF and MIX (P = 0.002). The proportion of bacterial N synthesized from ammonia 
      in the rumen was greater with STA than with NDF and MIX and was least for GLU (P 
      = 0.02). Irreversible ammonia loss and flux were lower (P = 0.09 and 0.02, 
      respectively) for GLU than for STA and NDF. As a percentage of the dose given, 
      cumulative secretion of (15)N ammonia in milk protein was greater for STA than 
      for GLU or NDF (P = 0.01 and 0.001, respectively). This experiment demonstrated 
      that provision of readily fermentable energy can decrease ammonia concentrations 
      in the rumen through decreased ammonia production (GLU), or through enhanced 
      uptake of ammonia for microbial protein synthesis (STA). Rapidly fermentable 
      energy in the rumen decreased ammonia production and flux, but the overall 
      efficiency of ammonia utilization for milk protein synthesis was only increased 
      by enhancing ruminal microbial ammonia uptake.
FAU - Hristov, A N
AU  - Hristov AN
AD  - Department of Animal and Veterinary Science, University of Idaho, Moscow 
      83844-2330. ahristov@uidaho.edu <ahristov@uidaho.edu>
FAU - Ropp, J K
AU  - Ropp JK
FAU - Grandeen, K L
AU  - Grandeen KL
FAU - Abedi, S
AU  - Abedi S
FAU - Etter, R P
AU  - Etter RP
FAU - Melgar, A
AU  - Melgar A
FAU - Foley, A E
AU  - Foley AE
LA  - eng
PT  - Comparative Study
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PT  - Research Support, U.S. Gov't, Non-P.H.S.
PL  - United States
TA  - J Anim Sci
JT  - Journal of animal science
JID - 8003002
RN  - 0 (Dietary Carbohydrates)
RN  - 0 (Nitrogen Isotopes)
RN  - 7664-41-7 (Ammonia)
RN  - 9005-25-8 (Starch)
RN  - IY9XDZ35W2 (Glucose)
SB  - IM
MH  - Ammonia/analysis/*metabolism
MH  - Animal Feed/analysis
MH  - Animals
MH  - Cattle/*metabolism
MH  - Dietary Carbohydrates/classification/*metabolism
MH  - Digestion/*physiology
MH  - Duodenum/metabolism
MH  - Female
MH  - Glucose/metabolism
MH  - Hydrogen-Ion Concentration
MH  - Isotope Labeling/veterinary
MH  - Lactation/*metabolism/physiology
MH  - Milk/chemistry
MH  - Nitrogen Isotopes/metabolism
MH  - Rumen/chemistry/*metabolism
MH  - Starch/metabolism
MH  - Time Factors
EDAT- 2005/01/13 09:00
MHDA- 2007/10/30 09:00
CRDT- 2005/01/13 09:00
PHST- 2005/01/13 09:00 [pubmed]
PHST- 2007/10/30 09:00 [medline]
PHST- 2005/01/13 09:00 [entrez]
AID - 83/2/408 [pii]
AID - 10.2527/2005.832408x [doi]
PST - ppublish
SO  - J Anim Sci. 2005 Feb;83(2):408-21. doi: 10.2527/2005.832408x.