Microbial Protein Synthesis and Flows of Nitrogen Fractions to the Duodenum of Dairy Cows

Clark, James H.; Klusmeyer, T.H.; McCarthy, Cameron

doi:10.3168/jds.s0022-0302(92)77992-2

Cited by 690 publications

(599 citation statements)

References 103 publications

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“…Christensen et al 1996) show that ruminal digestion of structural carbohydrates is not affected by supplementation of fat in dairy cows at higher intakes. Dry matter intake (DMI) has a great effect on ruminal digestion of OM and passage of microbial protein to the duodenum (Clark et al 1992) and may thus override many of the negative effects of fat supplementation (Merchen et al 1997). The DMI of bulls is clearly lower than that of high-producing dairy cows.…”

Section: Discussionmentioning

confidence: 99%

Effects of replacing different proportions of barley grain by barley fibre on performance of dairy bulls

Huuskonen¹,

Khalili²,

Joki‐Tokola³

2008

AFSci

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The objective of the present experiment was to study the effects of partial replacement of barley grain with barley fibre (BF) on animal performance, carcass traits and diet digestibility of growing dairy bulls. The feeding experiment comprised 20 Finnish Ayrshire bulls and 12 Holstein-Friesian bulls, and four treatments (8 bulls per treatment). There were four diets with two offered at stage 1 (from the initiation of the study to 450 kg live weight) and four at stage 2 (from 450 kg live weight to slaughter). The control diet (BF0) included grass silage (460 g kg -1 dry matter) and barley grain (540), BF25 diet included grass silage (460), barley grain (405) and BF (135), BF50 diet included grass silage (460), barley grain (270) and BF (270), and BF75 diet included grass silage (460), barley grain (135) and BF (405). At stage 1 there were only two treatments (BF0 and BF50) and at stage 2, all four treatments were included. All bulls were fed total mixed ration ad libitum. The mean initial live weight of the bulls was 261 kg and the mean final live weight 650 kg. At stage 1 there were no significant treatment differences in dry matter, energy or protein intakes or in live weight gain. At stage 2, replacing barley grain with BF led to a linear decrease of daily live weight gain (P < 0.05) and a linearly reduced feed conversion (kg dry matter kg -1 live weight gain) (P < 0.05). The apparent digestibility of the organic matter and neutral detergent fibre decreased linearly with increasing BF supplementation (P < 0.001). The dressing proportion and the carcass fat score decreased linearly (P < 0.05) with partial replacement of barley grain with BF. On carcass conformation, treatment had a significant (P < 0.05) quadratic effect: the BF25 and BF50 diets were classified highest. The results indicate that 50% of barley starch can be replaced with BF without affecting growth, but feed efficiency factors may decrease when barley starch is replaced with BF. At 75% replacement, feed intake was reduced, which resulted in a lower energy intake and reduced level of performance.

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Section: Discussionmentioning

confidence: 99%

Effects of replacing different proportions of barley grain by barley fibre on performance of dairy bulls

Huuskonen¹,

Khalili²,

Joki‐Tokola³

2008

AFSci

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“…Energy and nitrogen are the factors that may limit an animal's performance as a result of the restricted microbial synthesis in the rumen (Clark et al, 1992). With increasing ratio between protein and energy, the urea concentration in milk increases following an increase in blood urea N (Oltner and Wiktorsson, 1983).…”

Section: --mentioning

confidence: 99%

Effects of pressed beet pulp silage inclusion in maize-based rations on performance of high-yielding dairy cows and parameters of rumen fermentation

Boguhn

Kluth

Bulang

et al. 2010

Animal

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Beet pulp contains high amounts of pectins that can reduce the risk of rumen disorders compared to using feedstuffs high in starch. The objective was to study the effects of inclusion of ensiled pressed beet pulp in total mixed rations (TMR) for highyielding dairy cows. Two TMR containing no or about 20% (on dry matter (DM) basis) beet pulp silage were used. The beet pulp silage mainly replaced maize silage and corn cob silage. The TMR were intentionally equal in the concentrations of energy and utilisable crude protein (CP) at the duodenum. TMR were fed to 39 and 40 dairy cows, respectively, for 118 days. The average daily milk yield was about 43 kg/day. No significant differences in milk yield and milk fat or milk protein content were detected. DM intake of cows was significantly reduced by the inclusion of beet pulp silage (23.0 v. 24.5 kg/day). However, a digestibility study, separately conducted with sheep, showed a significantly higher organic matter digestibility and metabolisable energy concentration for the TMR that contained beet pulp silage. In vitro gas production kinetics indicated that the intensity of fermentation was lower in the TMR that contained beet pulp silage. In vitro production of short-chain fatty acids, studied using a Rusitec, did not differ between the TMR. However, the inclusion of beet pulp silage in the ration caused a significant reduction in the efficiency of microbial CP synthesis in vitro. The amino acid profile of microbial protein remained unchanged. It was concluded that beet pulp silage has specific effects on ruminal fermentation that may depress feed intake of cows but improve digestibility. An inclusion of beet pulp silage of up to 20% of DM in rations for high-yielding dairy cows is possible without significant effects on milk yield and milk protein or milk fat.

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“…Authors have reported increase in dry matter intake after postruminal protein infusion, indicating that part of the response is related to the metabolic effects, possibly mediated though improvements in the AA ratio and the energy in the tissue (Huhtanen et al, 2011). In addition, Clark et al (1992) reported that the microbial protein is accountable for most of the total metabolizable AA to the small intestine. Thus, the results for microbial protein synthesis (Table 4) in this study indicate that the microbial AA that reached the intestine were similar in the different protein sources, which maintained the energy-intake requirement.…”

Section: Discussionmentioning

confidence: 99%

Different true-protein sources do not modify the metabolism of crossbred Bos taurus × Bos indicus growing heifers

et al. 2015

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-The present study was conducted to investigate the effect of alternative true-protein sources to soybean meal, with different ruminal degradability, using a sugarcane-based diet, on nutrient digestion, ruminal fermentation, efficiency of microbial protein synthesis and passage rate in prepubertal dairy heifers. Eight crossbred rumen-and duodenum-cannulated Holstein × Gyr dairy heifers (202.0±11.5 kg BW) were evaluated in a 4 × 4 Latin square experimental design with four treatments and four periods in two simultaneous replicates. Dietary treatments were: soybean meal; cottonseed meal; peanut meal; and sunflower meal. When associated with diets containing sugarcane, the different protein sources did not affect intake or digestibility of dry mater, crude protein, organic matter and neutral detergent fiber. The average ruminal pH, NH 3 -N and concentration of total volatile fatty acids were not different among the diets supplied. The concentration of butyric acid was different among the protein sources, wherein the animals fed the diet with sunflower meal presented lower values than those fed the other sources. Diets did not affect nitrogen balance, microbial nitrogen, microbial synthesis efficiency, estimated dry matter flow, or passage rate. Alternative protein sources can be used to reduce the costs without changing the animal metabolism.

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Microbial Protein Synthesis and Flows of Nitrogen Fractions to the Duodenum of Dairy Cows

Cited by 690 publications

References 103 publications

Effects of replacing different proportions of barley grain by barley fibre on performance of dairy bulls

Effects of replacing different proportions of barley grain by barley fibre on performance of dairy bulls

Effects of pressed beet pulp silage inclusion in maize-based rations on performance of high-yielding dairy cows and parameters of rumen fermentation

Different true-protein sources do not modify the metabolism of crossbred Bos taurus × Bos indicus growing heifers

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