Volatile fatty acid proportions and microbial protein synthesis in the rumen of cattle receiving grass silage ensiled with different rates of formic acid

2006 ◽  
Vol 61 (3) ◽  
pp. 282-292 ◽  
Author(s):  
S. Jaakkola ◽  
V. Kaunisto ◽  
P. Huhtanen
2020 ◽  
Vol 4 (2) ◽  
pp. 839-847
Author(s):  
Daryoush Alipour ◽  
Atef Mohamed Saleem ◽  
Haley Sanderson ◽  
Tassilo Brand ◽  
Laize V Santos ◽  
...  

Abstract This study evaluated the effect of combinations of feed-grade urea and slow-release urea (SRU) on fermentation and microbial protein synthesis within two artificial rumens (Rusitec) fed a finishing concentrate diet. The experiment was a completely randomized, dose–response design with SRU substituted at levels of 0% (control), 0.5%, 1%, or 1.75% of dry matter (DM) in place of feed-grade urea, with four replicate fermenters per dosage. The diet consisted of 90% concentrate and 10% forage (DM basis). The experiment was conducted over 15 d, with 8 d of adaptation and 7 d of sampling. Dry matter and organic matter disappearances were determined after 48 h of incubation from day 9 to 12, and daily ammonia (NH3) and volatile fatty acid (VFA) production were measured from day 9 to 12. Microbial protein synthesis was determined on days 13–15. Increasing the level of SRU quadratically affected total VFA (Q, P = 0.031) and ammonia (Q, P = 0.034), with a linear increment in acetate (L, P = 0.01) and isovalerate (L, P = 0.05) and reduction in butyrate (L, P = 0.05). Disappearance of neutral detergent fiber (NDF) and acid detergent fiber (ADF) was quadratically affected by levels of SRU, plateauing at 1% SRU. Inclusion of 1% SRU resulted in the highest amount of microbial nitrogen associated with feed particles (Q, P = 0.037). Responses in the efficiency of microbial protein synthesis fluctuated (L, P = 0.002; Q, P = 0.001) and were the highest for 1% SRU. In general, the result of this study showed that 1% SRU in combination with 0.6% urea increased NDF and ADF digestibility and total volatile fatty acid (TVFA) production.


Author(s):  
J L Jacobs ◽  
A B McAllan

The addition to grass during ensiling of enzymes capable of hydrolysing forage polysaccharides has been shown to result in increased fermentation of dry matter within the silo (Jacobs & McAllan, 1987). Thus it appears that the enzymes promoted cellular breakdown within the silo. It is also possible that the enzymes may also have made available greater amounts of structural carbohydrate for utilisation within the rumen. Such an increase in available energy may be reflected in improved microbial activity in the rumen resulting in increased microbial protein synthesis. The present experiment examines the effects of enzyme treated silages on the flow of nitrogenous constituents at the duodenum of growing steers.


1996 ◽  
Vol 1996 ◽  
pp. 214-214
Author(s):  
J.W. Joo ◽  
W.J. Maeng ◽  
J.E. Cockburn ◽  
A.B. McAllan ◽  
H. Park ◽  
...  

Grass silage is considered to be asynchronous in the supply of energy and nitrogen to the rumen microbes. It is thought that this contributes towards the reduced quantities and efficiencies of rumen microbial protein synthesis frequently observed in animals feed on such diets (Beever, 1993). Additional energy from carbohydrates may help to ameliorate this situation. A rumen simulated continuous culture (RSCC) system was used to study the influence of supplementation of grass silage with various carbohydrate sources on rumen microbial activity.


1992 ◽  
Vol 119 (3) ◽  
pp. 411-418 ◽  
Author(s):  
S. Jaakkola ◽  
P. Huhtanen

SUMMARYFour Friesian bulls with ruminal and duodenal cannulae were used in a 4 × 4 Latin square experiment to study the effects of lactic acid (LA) on rumen fermentation and microbial protein synthesis. On a dry matter (DM) basis (g/kg), the basal diet comprised grass silage (700), barley (240) and rapeseed meal (60) and it was given at the rate of 7·1 kg DM/day. LA was infused continuously into the rumen at the rates of 0 (L0), 40 (L40), 80 (L80) or 120 (L120) g/kg basal diet DM.The molar proportion of propionate in the rumen volatile fatty acids (VFA) increased linearly (P < 0.001) and that of acetate, isovalerate, caproate (P < 0.01) and isobutyrate (P < 005) decreased linearly with an increasing rate of LA infusion. At the same time there was a linear decrease (P < 0.05) in the number of rumen protozoa. When the metabolic fate of infused LA was calculated on a molar basis, 0.21 of lactic acid was converted to acetate, 0·52 to propionate and 0.27 to butyrate.Infusion of LA into the rumen had no effect on the site or extent of the digestion of basal diet organic matter (OM) and neutral detergent fibre (NDF). LA diets tended to have a lower microbial N flow at the duodenum (71·4 v. 85·8 g N/day) and lower synthetic efficiency in the rumen (14·4 v. 20.4 g N/kg OM apparently fermented) when compared with the control diet. The ratio of duodenal non-ammonia N to N intake was highest with the control diet and lowest with L40, the effect of the LA rate being quadratic (P < 0·05). The results suggest that propionate was the main end-product of lactic acid fermentation in the rumen with the grass silage based diet. Lactic acid had no value as an energy source for microbial protein synthesis.


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