In situstudy of the relevance of bacterial adherence to feed particles for the contamination and accuracy of rumen degradability estimates for feeds of vegetable origin

2006 ◽  
Vol 96 (2) ◽  
pp. 316-325 ◽  
C. A. Rodríguez ◽  
J. González

Anin situstudy was conducted on four rumen-cannulated wethers to determine (using15N infusion techniques) the microbial contamination (mg bacterial DM or crude protein (CP)/100mg DM or CP) and the associated error on the effective degradability of fourteen feeds: barley and maize grains, soyabean and sunflower meals, full-fat soyabean, maize gluten feed, soyabean hulls, brewers dried grains, sugarbeet pulp, wheat bran, lucerne and vetch-oat hays, and barley and lentil straws. The DM or CP contamination in residues (M) fitted to single exponential or sigmoid curves. A general model (M=m(1−e−ft)j) was proposed to match this fit. Asymptotic values (m) varied from 2·84% to 13·3% and from 2·85% to 80·9% for DM and CP, respectively. Uncorrected results underestimated the effective degradability of both DM (P<0·05) and CP (P<0·01). For CP, this underestimation varied from 0·59% to 13·1%, with a higher but unascertainable error for barley straw. Excluding maize grain, the microbial contamination of both DM and CP, and the associated underestimation of the effective degradability of CP, were positively related to the cellulose content of the feed. The error in the effective degradability of CP was also negatively related to the CP content and its apparent effective degradability (R20·867). This equation allows easier and more accurate estimates of effective degradability, needed to improve protein-rationing systems.

2014 ◽  
Vol 153 (2) ◽  
pp. 361-370 ◽  
J. M. ARROYO ◽  
M. R. ALVIR ◽  

SUMMARYSodium sulphite is used in an optional way to remove insoluble proteins from neutral detergent fibre (NDF) residue. To determine whether the recovery of both NDF and insoluble nitrogen (N) in NDF solution (NDIN) are altered by its use, both parameters were measured in a set of 12 feeds, including cereal grains: maize (MG), rye (RG) and wheat (WG); cereal co-products: maize gluten feed (MGF), distilled dried grains from barley (DDGB) and wheat (DDGW) and wheat bran (WB); protein concentrates: rapeseed meal (RSM) and expeller palm kernel (EPK); dehydrated sugar beet pulp (DBP) and oat (OH) and ryegrass (RGH) hays. Associated effects on thein situeffective degradability (ED) of both NDF and NDIN were also studied in DDGW, WB, RSM, EPK, DBP, OH and RGH. Also, ED of acid detergent fibre (ADF) and its N (ADIN) were studied in hays. Errors due to microbial contamination in the rumen on the ED of NDF, ADF, NDIN and ADIN were also established in these last seven samples using15N infusion methods. Three rumen and duodenum cannulated wethers were used in the study. The sulphite use in NDF solution led to reductions (DDGB, DDGW, RSM and OH) and increases (RG, WG, WB and DBP) of the NDIN proportion, as well as the contribution of crude protein to NDF. These variations were associated with irregular effects on NDF residues and on ED of both NDIN and NDF. As a consequence, sulphite use does not assure the reduction of the insoluble protein contamination and it may even increase it. This methodology may also alter the degradability estimates of NDIN or NDF. Mean ruminal microbial contamination in NDF was 7·0, 10·8, 13·3, 5·4, 12·0, 35·3 and 20·0 g/kg in WB, DDGW, RSM, EPK, DBP, OH and RGH, respectively. The associated contents of microbial N in NDIN were: 59·3, 29·9, 26·2, 19·8, 37·3, 441 and 150 g/kg, respectively. Microbial contamination in ADF and ADIN (g/kg) was 3·6 and 94·5 in OH and 1·7 and 41·2 in RGH. Not correcting this contamination led to consistent undervaluations of ED of NDIN and NDF in all tested feeds, although errors only reached significance for NDIN in hays and DBP. Microbial-corrected ED of NDIN was 0·685, 0·826, 0·481, 0·389, 0·166, 0·718 and 0·425 in WB, DDGW, RSM, EPK, DBP, OH and RGH, respectively, whereas values for ADIN were 0·504 (OH) and 0·469 (RGH).

1999 ◽  
Vol 79 (3) ◽  
pp. 343-351 ◽  
G. W. Mathison ◽  
R. Soofi-Siawash ◽  
E. K. Okine ◽  
J. Helm ◽  
P. Juskiw

Chemical composition and in situ ruminal degradability characteristics for 25 and 40 genotypes of barley straw were measured for crops grown in 1994 and 1995, respectively. Straw from semidwarf genotypes contained more crude protein and less neutral detergent fiber (NDF) than that from genotypes with medium straw length and effective ruminal degradability was 9% higher (P < 0.01). Straw from two-row genotypes contained 19% more crude protein (4.4 vs. 3.7%) and 3% less NDF (75.2 vs. 77.6%) than that from six-row genotypes and effective ruminal degradability was 6% higher (P < 0.01) when genotypes with medium-length straw only were considered. Genotypes with smooth awns had higher rates of degradation but contained less of the slowly degraded fraction than straw with rough awns when straws of medium straw length were compared (P < 0.05). Straw from hulless genotypes contained more (P = 0.006) NDF than that from covered varieties. Both ambient and soil temperature were positively related (P < 0.05) to effective ruminal degradability of straw, possibly because of associated greater leafiness when temperatures were higher and there was more light. It was concluded that it is possible to select barley genotypes that have superior straw nutritive value for ruminant animals. Key words: Barley, straw, degradability, cattle, genotype, environment

H.M. Ferreiro ◽  
J.D. Sutton ◽  
A. Boodoo ◽  
D.J. Napper

Alkali treatment increases the digestibility of straw but processing methods and the effectiveness differ widely. The aim of this study was to compare an on-farm method producing chopped straw (C) with an industrial process producing coarsely ground straw (Viton) (G) (Wilson and Brigstocke, 1967).Four dry Friesian cows, each with a large rumen cannula and a simple cannula in the proximal duodenum, were given (kg dry matter (DM)/day): 3.4 concentrate (180 g crude protein/kg DM) and 3.1 C or G alkali-treated straws in one meal daily in a simple change-over design. A single batch of spring barley straw was used and was treated with about 40 g NaOH/kg either by an on-farm process giving particles about 10 cm long (C) or by an industrial process giving coarsely-ground straw in a pellet (Viton) (G). Spot samples of digesta were taken from the duodenum for measurement of digestion in the stomach, using chromic oxide paper, and for measurement of the rate of passage of indigestible residues using magenta-stained straw. Eating behaviour and reticular movements were measured by use of balloons (Balch, 1971). Straw DM digestibility was measured over 48 h in vitro and by dacron bags (in situ) (Ørskov and McDonald, 1979).

2013 ◽  
Vol 53 (2) ◽  
pp. 134 ◽  
J. A. Guevara-González ◽  
J. González ◽  
J. M. Arroyo ◽  
V. J. Moya ◽  
O. Piquer

Effects of considering the particle comminution rate (kc) in addition to particle rumen outflow (kp) and the ruminal microbial contamination on estimates of by-pass and intestinal digestibility of DM, organic matter and crude protein were examined in perennial ryegrass and oat hays. By-pass kc-kp-based values of amino acids were also determined. This study was performed using particle transit, in situ and 15N techniques on three rumen and duodenum-cannulated wethers. The above estimates were determined using composite samples from rumen-incubated residues representative of feed by-pass. Considering the comminution rate, kc, modified the contribution of the incubated residues to these samples in both hays and revealed a higher microbial contamination, consistently in oat hay and only as a tendency for crude protein in ryegrass hay. Not considering kc or rumen microbial contamination overvalued by-pass and intestinal digestibility in both hays. Therefore, non-microbial-corrected kp-based values of intestinal digested crude protein were overestimated as compared with corrected and kc-kp-based values in ryegrass hay (17.4 vs 4.40%) and in oat hay (5.73 vs 0.19%). Both factors should be considered to obtain accurate in situ estimates in grasses, as the protein value of grasses is very conditioned by the microbial synthesis derived from their ruminal fermentation. Consistent overvaluations of amino acid by-pass due to not correcting microbial contamination were detected in both hays, with large variable errors among amino acids. A similar degradation pattern of amino acids was recorded in both hays. Cysteine, methionine, leucine and valine were the most degradation-resistant amino acids.

2016 ◽  
Vol 56 (12) ◽  
pp. 2029 ◽  
F. Díaz-Royón ◽  
J. M. Arroyo ◽  
M. D. Sánchez-Yélamo ◽  
J. González

The effects of solutions of malic or orthophosphoric acids (0.752 Eqg/kg of feed) and heat to protect proteins of sunflower meal (SFM) and spring pea (SP) against ruminal degradation were studied using particle transit, 15N infusion, in situ and electrophoretic techniques. Three wethers fitted with rumen and duodenum cannulae were successively fed three isoproteic diets including SFM and SP, untreated or treated with malic or orthophosphoric acids. Incubations of tested meals were only performed while feeding the respective diet. Estimates of the ruminally undegraded fraction (RU) and its intestinal digestibility of dry matter, organic matter (only for RU), crude protein and starch (only in SP) were obtained considering ruminal microbial contamination and particle comminution and outflow rates. When corrected for microbial contamination, estimates of RU and intestinal digestibility decreased in all tested fractions for both feeds. All RU estimates increased with the protective treatments, whereas intestinal digestibility-dry matter also increased in SFM. Low intestinal digestibility-crude protein values suggested the presence of antitrypsin factors in SP. Protective treatments of both feeds led to consistent increases in the intestinal digested fraction of dry matter and crude protein, being only numerically different for SP-starch (60.5% as average). However, treatments also reduced the organic matter fermentation, which may decrease ruminal microbial protein synthesis. Electrophoretic studies showed albumin disappearance in both SFM and SP, whereas changes in other RU proteins were more pronounced in SP than SFM.

2006 ◽  
Vol 82 (1) ◽  
pp. 75-81 ◽  
J. González ◽  
J. Faría-Mármol ◽  
C.A. Rodríguez ◽  
M. Ouarti ◽  
M.R. Alvir ◽  

AbstractThe effective ruminal degradability (ED) of dry matter (DM), crude protein (CP) and amino acids, and the effective intestinal digestibility (IED) of DM and CP of a sample of whole cottonseed was measured using in situ and rumen outflow rate techniques in three wethers cannulated in the rumen and duodenum. The microbial contamination of rumen incubated residues was corrected by a continuous rumen infusion of15NH3as microbial marker and rumen solid associated bacteria as reference sample. Microbial contamination resulted in an overestimation of the undegradable fraction of DM (0·291v. 0·275;P<0·05) and CP (0·071v. 0·037;P<0·01) and a small underestimation of ED of DM (0·500v. 0·512;P=0·09) and CP (0·755v. 0·779;P=0·052). A proportion of 0·1 of the ruminal undegraded CP was of microbial origin and for essential amino acids this proportion varied from 0·042 to 0·150. Differences in ED between amino acids modified the amino acid profile, with an important reduction (0·2;P<0·01) in the proportion of lysine. Apparent intestinal digestibility of the insoluble fraction of this food, measured with the mobile nylon bag technique, showed large reductions (P<0·001) with the increase of the ruminal incubation time between 0 and 72 h: from 0·392 to 0·026 for DM and from 0·851 to 0·099 for CP. These evolutions fitted an exponential function with a previous lag. The IED was estimated either by integration of these equations and those describing the ruminal degradation and rumen outflow or by incubation through the intestines of a sample pooled to be representative of rumen flow of the undegraded food. The two methods gave similar values for both DM (0·222v. 0·203) and CP (0·659v. 0·658).

2016 ◽  
Vol 94 (suppl_5) ◽  
pp. 737-737
A. C. B. Menezes ◽  
S. C. Valadares Filho ◽  
P. P. Rotta ◽  
S. A. Santos ◽  
D. Zanetti ◽  

1966 ◽  
Vol 2 (2) ◽  
pp. 101-105 ◽  
Adeboyejo A. Fayemi

SummaryA four-year study from 1958 to 1962 showed that time of application of fertilizer nitrogen greatly influenced the yield of grain, the percentage of nitrogen and the crude protein of the grain under Nigerian conditions characteristic of the early maize cropping season from March to July. Split applications of nitrogen fertilizer significantly increased maize grain yield by 35 per cent when two equal doses were given one month and two months after planting; and by 31 per cent when four equal doses were supplied at planting and one month, two months and three months after seeding. Yield was significantly reduced when application was delayed two months after planting. High yields of maize were not obtained by supplying the whole of nitrogen fertilizer at one time, eidier at sowing or any time later during the growing season. However, applying all of the nitrogen fertilizer one month after planting significantly increased the percentage of nitrogen and of the crude protein content of the grain. The maize ear weight was favourably influenced by spreading the nitrogen application over the three-month period of the maize growth.

1970 ◽  
Vol 12 (1) ◽  
pp. 63-70 ◽  
H. Swan ◽  
G. E. Lamming

SUMMARY1. Three groups, each of eight steers, were fed on pelleted diets containing 30, 50 or 70% ground barley straw, maize and soya bean meal. On an air-dry basis the diets contained 12% crude protein.2. Daily live-weight gain was 1·29, 1·19 and 1·02 kg/day for the 30, 50 and 70% straw diets respectively, and was negatively related to the percentage of crude fibre in the dry matter (r = −0·61, P < 0·05).3. The apparent digestibility of dry matter, determined in sheep at the maintenance level of feeding was negatively related to percentage crude fibre in the dry matter (r = −0·91, P < 0·001).4. All animals were killed at approximately the same live weight, which was reached on average in 140,153 and 163 days by the 30, 50 and 70% groups, respectively.5. The differences in mean carcass weight between treatments were significant (P < 0·05). Killing-out percentage was significantly reduced (P < 0·05) as the proportion of ground barley straw in the diet was increased from 30 to 70%.6. The proportion of straw in the diet had no direct effect on the composition of carcass gain.7. The results are discussed in relation to the intake of digestible energy.

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