Relationship between the Concentrations of Crude Protein and Apparently Digestible Protein in Forages

Holter, James A.; Reid, J. T.

doi:10.2527/jas1959.1841339x

Cited by 97 publications

(40 citation statements)

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“…As expected, the apparent total tract N digestion increased linearly (P<0.01) as the urea levels increased. This increase is partly due to the digestibility of urea and partly due to the increasing concentration of CP in the diet as the urea level increased (Holter and Reid 1959). Adjusting for the faecal loss of metabolic protein (Swanson 1977, NRC 1985, the true digestion of protein in the present study was 91.84%, similar to the average of the previous measurements summarised by the National Research Council (NRC 1985).…”

Section: Discussionsupporting

confidence: 85%

Site and extent of digestion of nitrogen compounds and organic matter in steers fed a finishing diet with dried distillers grains plus solubles supplemented with urea

Urías-Estrada

Ramos-Méndez

González-Vizcarra

et al. 2019

Austral j. vet. sci.

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Four Holstein steers (266 ± 13 kg) with ruminal and duodenal cannulae were used to evaluate the effect of inclusion of different levels of urea (0%, 0.4%, 0.8% and 1.2%) in a steam-flaked, corn-based finishing diet containing dried distillers grains plus solubles (DDGS) on the site and extent of N compounds and organic matter (OM) digestion, and on the ruminal N-NH3 and blood concentrations of urea nitrogen. Increasing the urea levels linearly decreased the OM flow to the duodenum (P<0.04) and increased the total N and non-ammoniacal N flow to the duodenum (P<0.01), which resulted from linear increases in the flow of microbial N and NH 3 -N (P<0.01) without affecting the feed residual N flow (P≥0.47). Increasing the urea levels linearly increased ruminal digestion of OM and dietary N (P≤0.03), and decreased protein efficiency (P<0.01) without affecting microbial efficiency. The urea supplementation did not affect post-ruminal digestion. Urea supplementation linearly increased (P<0.01) total tract digestion of N compounds without affecting total tract digestion of OM. Ruminal pH averaged 6.09 ± 0.03 and was not affected (P≥0.97) by the inclusion of urea. Ruminal NH 3 -N concentration increased with urea supplementation (linear component, P<0.01). The same effect was observed for blood urea concentrations and plasma urea (P<0.01). On the basis of the results observed here, urea can be incorporated in finishing corn-based diets that include DDGS. However, this must done carefully to avoid exceeding the RDP concentration in the diets in order to optimise ruminal fermentation and reduce the risk of high N excretion in the faeces. This is relevant when higher levels of DDGS are included in the diets (i.e. 30%).

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Section: Discussionsupporting

confidence: 85%

Site and extent of digestion of nitrogen compounds and organic matter in steers fed a finishing diet with dried distillers grains plus solubles supplemented with urea

Urías-Estrada

Ramos-Méndez

González-Vizcarra

et al. 2019

Austral j. vet. sci.

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“…Total tract N digestibility was also 8.6% lower ( P < .01) for SFC. The expected difference in N digestibility between the two grain types as a result of differences in N content of the diets was 12.2% (based on the relationship between the concentration of crude protein and apparently digestible protein; Holter and Reid, 1959). Total tract digestion of OM, starch, DE, and ME were 3.3, 1.1, 4.1, and 8.1%, respectively, greater ( P < .05) for SFC than for barley diets.…”

Section: Resultsmentioning

confidence: 99%

Influence of processing on the comparative feeding value of barley for feedlot cattle

1993

Journal of Animal Science

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Ninety-six crossbred steers were used in a 172-d feedlot growth performance trial to determine the effects of type processing on the comparative feeding value of barley in a 90% concentrate finishing diet. Treatments were: 1) steam-flaked corn (SFC; density = .31 kg/L); 2) dry-rolled barley (DRB; density = .39 kg/L); 3) steam-rolled barley, coarse roll (SRB-C, density = .39 kg/L); and 4) SRB, thin roll (SRB-T, density = .19 kg/L). The ADG was similar (P > .10) across barley treatments, averaging 1.29 kg/d. Feed intake (P < .05) was lower for SRB than for DRB. Diet NE was greater (P < .05) for SRB than for DRB. Feed intake was lower (P < .05) for SFC than for barley diets. The influence of grain processing on characteristics of digestion was evaluated using four Holstein steers (average BW = 230 kg) with cannulas in the rumen and proximal duodenum. Ruminal and total tract digestibility of OM and starch were lower (P < .05) for DRB than for SRB. Ruminal and total tract digestibility of OM and starch were similar (P > .10) for SRB-C and SRB-T. However, passage of nonammonia N was markedly increased (26.9%, P < .01) with SRB-T compared with SRB-C. This increase in ruminal N efficiency was due partly to reduced ruminal degradation of feed N (23.4%, P < .01) and partly to increased microbial N synthesis (13.3%, P > .10). The comparative feeding value of DRB, SRB-C, and SRB-T in this study was 90, 92, and 96% the value of SFC, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

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“…Any comparison between these studies depends upon the conversion procedure used between the various units of nutritive value. If Holter and Reid's (15) relationship between CP and DCP is used, the absolute evaluation of protein in dried forage is similar in each study, but Alderman's marginal value for protein is rather higher. The marginal value of ME derived here is considerably higher than that calculated by Alderman (2), but this is almost certainly due to the much lower cereal prices used in the latter case.…”

Section: Inclusion Price For Dried Grassmentioning

confidence: 93%

Economic Aspects of the Inclusion of Dried Grass in Dairy‐cow Rations

Crabtree

1971

Grass and Forage Science

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A linear programming model was formulated to calculate a least-cost ration for lactating dairy cows with respect to certain nutritional constraints. The model was used to derive the price at which dried forage of a stated digestihle crude protein content (DCP) and metabolizable energy content (ME) would just become included in a least-cost feed. Marginal costs for DCP and ME of £0 057/ kg and £00096/Mca!, respectively, were calculated. These were found to be fairly Insensitive to changes in milk yield. Inclusion prices were slightly lower than current market prices. related only to its protein content, but the production level achieved by ruminants is cJearly, in part, a function of their intake of energy (4). In farm practice, therefore, the value of dried grass for ruminants should be determined not only by protein content but also by energy value and possibly by other dietary considerations.This paper attempts to examine the economics of the inclusion of dried grass in rations for dairy cows. It is specifically directed towards defining the price at which dried forages differing in composition compete with other available feeds for inclusion in rations.

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Relationship between the Concentrations of Crude Protein and Apparently Digestible Protein in Forages

Cited by 97 publications

References 0 publications

Site and extent of digestion of nitrogen compounds and organic matter in steers fed a finishing diet with dried distillers grains plus solubles supplemented with urea

Site and extent of digestion of nitrogen compounds and organic matter in steers fed a finishing diet with dried distillers grains plus solubles supplemented with urea

Influence of processing on the comparative feeding value of barley for feedlot cattle

Economic Aspects of the Inclusion of Dried Grass in Dairy‐cow Rations

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