scholarly journals Investigation of nitrogen balance in dairy cows and steers nourished by intragastric infusion

1983 ◽  
Vol 50 (1) ◽  
pp. 99-107 ◽  
Author(s):  
E. R. Ørskov ◽  
N. A. MacLeod ◽  
S. T. M. Fahmy ◽  
L. Istasse ◽  
F. D. DeB. Hovell

1. Two dairy cows were maintained by intragastric infusion of volatile fatty acids and casein. Except when fasting, the casein-nitrogen was held constant, while total gross energy supply was varied from zero during fasting to 650 kJ/kg body-weight (W)0·75.2. One cow was estimated to attain zero N balance at an energy intake of 255 kJ/kg W0·75and the other at 307 kJ/kg W0·75, which was calculated to be substantially below the estimated energy required for zero energy balance.3. When the cows were later given an N-free infusion for a period preceding the trial, N balance occurred at 98 kJ/kg W0·75for one cow and 115 kJ/kg W0·75for the other.4. Four steers were similarly nourished by intragastric infusion and the energy nutrient increased from 0 at fasting to 450 kJ/kg W0·75. The protein was held constant at 1 g N/kg W0·75except at fasting. The energy level at which N balance occurred was 154 (SE 38) kJ/kg W0·75or approximately equal to the energy content of the protein. The practical implications of these findings are discussed.

Author(s):  
A T Chamberlaina ◽  
K Seyoum ◽  
D Chapman ◽  
C Piotrowski

The UK metabolisable protein system (AFRC, 1992) requires the measurement of fermentable metabolisable energy (FME) to determine the potential yield of microbial crude protein in the rumen. FME is defined as:The objective of this work was to measure the ME , ether extract and volatile fatty acid components of first cut grass silages to assess the range of FME and non-fermentable fractions and hence the range of fermentabilities (FME:ME).Eighty-four clamp grass silages, predominantly first-cut rye grass, were analysed for modified acid detergent fibre (MADF), individual volatile fatty acids, oil (ether extract) and oven dry matter. ME was predicted from the MADF after correction for oven dry matter. The gross energy of the lactic, acetic, propanoic, butyric and valeric acid were taken to be 15.2, 14.6, 20.8, 24.9, and 28.0 MJ/kg DM, and for the Ether Extract fraction of grass 38.5 MJ/kg DM. The energy content of the volatile fatty acids in the silage were summed and FME was calculated as described above. The fermentability of the silage was the expressed as the proportion of FME to ME.


2021 ◽  
Vol 26 (4) ◽  
pp. 2788-2792
Author(s):  
VASILE BOGHIAN

The ruminal acidosis is a decrease in the ruminal pH by the accumulation of acidic metabolites at this level. As a result, the proportion of ruminal volatile fatty acids and glycaemia changes with immediate repercussions on the milk production. Of the total ruminant-reticular indigestions diagnosed in a lot of 370 cows, 37.9% were represented by ruminal acidosis. Out of these, most of the cases (90.9%) had a subacute evolution, which implies difficulties of diagnosis under farm conditions. On the other hand, the amount of milk was, on average, smaller with 1.7 liters in cows with ruminal acidosis compared to the clinically healthy cows. Milk fat decreased from 3.8% to 2.8% in sick cows, by an average of 1% and had a coefficient of variation of individual values almost double compared to the values obtained in clinically healthy cows. This shows the direct implication of ruminal acidosis over milk production. Appart of ruminal paresis and indigestion, milk production’s impairment is an important clinical sign in most of the dairy cows with ruminal acidosis.


1990 ◽  
Vol 73 (8) ◽  
pp. 2168-2178 ◽  
Author(s):  
D.E. Otterby ◽  
D.G. Johnson ◽  
R. Towns ◽  
R.M. Cook ◽  
R.A. Erdman ◽  
...  

2011 ◽  
Vol 79 (1) ◽  
pp. 16-25 ◽  
Author(s):  
Qendrim Zebeli ◽  
Sarah J Terrill ◽  
Alberto Mazzolari ◽  
Suzanna M Dunn ◽  
Wen Z Yang ◽  
...  

This study evaluated the effects of intraruminal administration ofMegasphaera elsdeniion ruminal fermentation patterns, the profile of plasma metabolites, and milk yield and composition of mid-lactation dairy cows. Eight primiparous, ruminally cannulated Holstein cows were arranged in a paired 2×2 crossover design. Cows were randomly assigned to one of two treatments: 1) intraruminal inoculation of 35 ml suspension per day ofM. elsdeniiATCC 25940 (MEGA), containing 108cfu/ml of bacteria, dissolved in 35 ml of saline (0·15m), or 2) carrier alone (35 ml saline; CTR). Both postprandial and preprandial rumen volatile fatty acids (VFA) and plasma metabolite measurements were analysed. Postprandial VFA patterns were affected the most, with butyrate (P<0·01) and valerate (P<0·01) proportions increasing, and acetate (P<0·01), isobutyrate (P=0·05) and isovalerate (P<0·01) decreasing in MEGA cows. Preprandial data measured at various days showed that MEGA dosage tended to increase the molar proportion of propionate (P=0·09) and lower the acetate to propionate ratio (P=0·07) in the rumen fluid. There was no effect of treatment on rumen pH and on the concentration of lactate in the rumen as well as on selected preprandial plasma metabolites. Postprandial plasma concentrations of cholesterol tended to increase (P=0·07) in MEGA cows compared with CTR. Concentrations of non-esterified fatty acids (NEFA) in the plasma were lower in MEGA cows after the morning feeding (P<0·01). Sampling hour also affected plasma NEFA in this study. Plasma β-hydroxybutyrate (BHBA) were not affected by the treatment (P>0·05); however, after the morning feeding BHBA concentration was increased in both groups of cows. Dry matter intake and milk yield and composition were not affected by treatment. In conclusion, results indicate thatM. elsdeniihas the potential to modulate the rumen fermentation profile in mid-lactation Holstein cows, but these effects were only slightly reflected in changes in plasma metabolites and milk composition.


1993 ◽  
Vol 69 (2) ◽  
pp. 385-396 ◽  
Author(s):  
Jan Dijkstra ◽  
Huug Boer ◽  
Jaap Van Bruchem ◽  
Marianne Bruining ◽  
Seerp Tamminga

The effect of rumen liquid volume, pH and concentration of volatile fatty acids (VFA) on the rates of absorption of acetic, propionic and butyric acids from the rumen was examined in lactating dairy cows. Experimental solutions introduced into the emptied, washed rumen comprised two different volumes (10 or 30 1), four levels of pH (4.5, 5.4, 6.3, 7.2) and three levels of individual VFA concentrations (20, 50 or 100 mM-acetic, propionic or butyric acid). All solutions contained a total of 170 mM-VFA and an osmotic value of 400 mOsmol/l. Absorption rates were calculated from the disappearance of VFA from the rumen corrected for passage with liquid phase to the omasum. An increase in initial fluid pH caused a reduction in fractional absorption rates of propionic and butyric acids. Increasing the initial pH from 4.5 to 7.2 reduced fractional absorption rates of acetic, propionic and butyric acids from 0.35, 0.67 and 0.85 to 0.21, 0.35 and 0.28/h respectively. The fractional absorption rates of all VFA were reduced (P < 0.05) by an increase in initial rumen volume. The fractional absorption rate of acetic acid was lower (P < 0.05) at an initial concentration of 20 mM than of 50 mM. The fractional absorption rate of propionic acid tended (P < 0.10) to decrease as the level of concentration increased while fractional absorption rate of butyric acid was not affected by butyric acid concentration. These results indicate that relative concentrations of VFA in rumen fluid might not represent relative production rates and that attempts to estimate individual VFA production from substrate digestion must take account of pH and VFA concentration.


1967 ◽  
Vol 47 (1) ◽  
pp. 31-38 ◽  
Author(s):  
R. A. Clarke ◽  
W. K. Roberts

Two metabolism experiments were conducted with rumen-fistulated sheep to study effects of increasing dietary levels of unsaturated fatty acids upon ration digestibility and rumen-fluid volatile fatty acids. Apparent digestibility of ration components was not significantly (P > 0.05) affected by diet. However, crude fat digestibility values, which include fecal soap excretion, were 11–19 digestion units lower than comparable ether extract values. When diets high in unsaturated fatty acids were fed, the rumen and fecal levels of these acids were lower than dietary levels, suggesting that hydrogenation of C-18 polyethnoid fatty acids was occurring. Fecal soap excretion was affected very little by dietary unsaturated fatty acids, but stearic acid proportion of fecal soaps increased as the level of dietary unsaturated fatty acids increased. The ratios of acetic to propionic acid gradually decreased as the unsaturated fatty acids of the ration increased in one experiment, but in the other experiment no consistent pattern was observed.


1965 ◽  
Vol 64 (1) ◽  
pp. 67-75 ◽  
Author(s):  
I. H. Bath ◽  
J. A. F. Rook

Information on the effect of the inclusion of typical farm foods in the diets of cattle on the ruminal concentrations of the individual volatile fatty acids (V.F.A.'s) is limited. The most extensive investigations are those of Balch & Rowland (1957) and Shaw and his co-workers (see Shaw, 1961), which have given values for a variety of hay and concentrate diets. Few figures are available for other types of cattle foods. The present paper describes a study of the V.F.A.'s in the rumen of dairy cows given various roughages or succulent foods, including a range of herbages of different species and at different stages of growth.


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