Effects of silage fermentation on milk protein and fat content and yield

The extent and type of in-silo fermentation has a profound influence on the composition of nutrients absorbed from the digestive tract of dairy cows (Choung & Chamberlain, 1993; van Vuuren et al. 1995). The amount of amino acids absorbed from the small intestine decreases when the extent of in-silo fermentation is increased due to reduced efficiency of microbial protein synthesis. The ratio of lipogenic to glucogenic VFA increases when in-silo fermentation is restricted, since silage lactic acid generally increases propionate in rumen VFA, whereas WSC in silage increases acetate, butyrate or both. The purpose of this study was to estimate quantitative relationships between silage fermentation characteristics and milk production using data based on mean treatment values of production parameters and silage fermentation characteristics.

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Effect of Rumen Available Protein, Amimo Acids and Carbohydrates on Microbial Protein Synthesis, Amino Acid Flow and Performance of High Yielding Cows

10.32747/1993.7568103.bard ◽

1993 ◽

Author(s):

Gabriella A. Varga ◽

Amichai Arieli ◽

Lawrence D. Muller ◽

Haim Tagari ◽

Israel Bruckental ◽

...

Keyword(s):

Protein Synthesis ◽

Amino Acid ◽

Dairy Cows ◽

Milk Protein ◽

Protein Yield ◽

Microbial Protein ◽

Feeding Frequency ◽

Rumen Undegradable Protein ◽

And Performance

The effect of rumen available protein amino acids and carbohydrates on microbial protein synthesis, amino acid flow and performance of high yielding dairy cows was studied. A significant relationship between the effective degradabilities of OM in feedstuffs and the in vivo ruminal OM degradation of diets of dairy cows was found. The in situ method enabled the prediction of ruminal nutrients degradability response to processing of energy and nitragenous supplements. The AA profile of the rumen undegradable protein was modified by the processing method. In a continuous culture study total N and postruminal AA flows, and bacterial efficiency, is maximal at rumen degradable levels of 65% of the CP. Responses to rumen degradable non carbohydrate (NSC) were linear up to at least 27% of DM. Higher CP flow in the abomasum was found for cows fed high ruminally degradable OM and low ruminally degradable CP diet. It appeared that in dairy cows diets, the ratio of rumen degradable OM to rumenally degradable CP should be at least 5:1 in order to maximize postruminal CP flow. The efficiency of microbial CP synthesis was higher for diets supplemented with 33% of rumen undegradable protein, with greater amounts of bacterial AA reaching the abomasum. Increase in ruminal carbohydrate availability by using high moisture corn increased proportions of propionate, postruminal nutrients flow, postruminal starch digestibility, ruminal availability of NSC, uptake of energy substrates by the mammory gland. These modifications resulted with improvement in the utilization of nonessential AA for milk protein synthesis, in higher milk protein yield. Higher postruminal NSC digestibility and higher efficiency of milk protein production were recorded in cows fed extruded corn. Increasing feeding frequency increased flow of N from the rumen to the blood, reduced diurnal variation in ruminal and ammonia, and of plasma urea and improved postruminal NSC and CIP digestibility and total tract digestibilities. Milk and constituent yield increased with more frequent feeding. In a study performed in a commercial dairy herd, changes in energy and nitrogenous substrates level suggested that increasing feeding frequency may improve dietary nitrogen utilization and may shift metabolism toward more glucogenesis. It was concluded that efficiency of milk protein yield in high producing cows might be improved by an optimization of ruminal and post-ruminal supplies of energy and nitrogenous substrates. Such an optimization can be achieved by processing of energy and nitrogenous feedstuffs, and by increasing feeding frequency. In situ data may provide means for elucidation of the optimal processing conditions.

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The addition of lactose to the diets of dairy cows fed protected fats

Proceedings of the British Society of Animal Science ◽

10.1017/s1752756200594514 ◽

1997 ◽

Vol 1997 ◽

pp. 10-10

Author(s):

R.D. Allison ◽

P.C. Garnsworthy

Keyword(s):

Amino Acids ◽

Dairy Cows ◽

Protein Content ◽

Milk Protein ◽

Early Lactation ◽

Microbial Protein ◽

Available Energy ◽

Milk Protein Content ◽

Metabolisable Energy ◽

Fat Supplements

Rumen inert fats are often included in dairy rations to increase the metabolisable energy (ME) supply whilst maintaining rumen function. Protected fat supplements have been shown to increase milk yields and fat content but with an associated and undesirable reduction in protein content. A reduced intake of rumen available energy (FME) may limit the microbial protein yield and so reduce the supply of amino acids to the mammary gland. Lactose supplements have been shown to increase the flow of microbial protein to the intestines (Chamberlain et al, 1993) and to reduce the effect of protected fats on milk protein content during early lactation (Garnsworthy, 1996). A trial was conducted to determine whether lactose supplementation could reduce the effects of protected fats on milk protein content during mid lactation.

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Whole-body fluxes and partitioning of amino acids to the mammary gland of cows fed fresh pasture at two levels of intake during early lactation

British Journal Of Nutrition ◽

10.1079/bjn2003886 ◽

2003 ◽

Vol 90 (2) ◽

pp. 271-281 ◽

Cited By ~ 3

Author(s):

D. Pacheco ◽

M.H. Tavendale ◽

G. W. Reynolds ◽

T. N. Barry ◽

J. Lee ◽

...

Keyword(s):

Amino Acids ◽

Protein Synthesis ◽

Mammary Gland ◽

Dairy Cows ◽

Milk Protein ◽

Essential Amino Acids ◽

Whole Body ◽

Early Lactation ◽

Isoleucine Leucine ◽

Ad Libitum

The utilisation of essential amino acids (EAA) by the mammary gland of lactating dairy cows fed fresh forages was studied to provide basic information useful in designing strategies to increase the production of milk protein from pasture-fed dairy cows. The relationship between the flux of EAA in the whole body and their uptake by the mammary gland was determined in four cows in early lactation (length of time in milk 44 (SD 14·5) d) producing 21 (SD 4·0) kg milk/d. The cows were maintained in metabolism stalls and fed fresh perennial ryegrass (Lolium perenne) and white clover (Trifolium repens) pasturead libitumor restricted to 75 %ad libitumintake. The whole-body fluxes of amino acids (AA) were measured using an arterio-venous infusion of universally13C-labelled AA. Whole-body fluxes of fourteen AA were estimated. Isotope dilution indicated that mammary utilisation accounted for one-third of the whole-body flux of EAA, with individual AA ranging between 17 and 35 %. Isoleucine, leucine, valine and lysine were the EAA with the greatest partitioning towards the mammary gland (up to 36 % of the whole-body flux), which could reflect a potentially limiting effect on milk protein synthesis. In the case of AA with low partitioning to the mammary gland (for example, histidine), it is suggested that non-mammary tissues may have priority over the mammary gland and therefore the supply of this AA may also limit milk protein synthesis.

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Effects of jugular-infused lysine, methionine, and branched-chain amino acids on milk protein synthesis in high-producing dairy cows

Journal of Dairy Science ◽

10.3168/jds.2010-3442 ◽

2011 ◽

Vol 94 (4) ◽

pp. 1952-1960 ◽

Cited By ~ 48

Author(s):

J.A.D.R.N. Appuhamy ◽

J.R. Knapp ◽

O. Becvar ◽

J. Escobar ◽

M.D. Hanigan

Keyword(s):

Amino Acids ◽

Protein Synthesis ◽

Dairy Cows ◽

Milk Protein ◽

Branched Chain Amino Acids ◽

Branched Chain

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Limitations in digestible methionine in the intestine (MetDI) for milk protein secretion in dairy cows fed a ration based on grass silage

Proceedings of the British Society of Animal Science ◽

10.1017/s030822960002924x ◽

1995 ◽

Vol 1995 ◽

pp. 158-158

Author(s):

Y. Chilliard ◽

J. Rouel ◽

A. Ollier ◽

J. Bony ◽

K. Tanan ◽

...

Keyword(s):

Protein Synthesis ◽

Small Intestine ◽

Dairy Cows ◽

Protein Secretion ◽

Milk Protein ◽

Microbial Protein ◽

Maize Silage ◽

Microbial Protein Synthesis ◽

Grass Silage

The interest for increasing post-ruminal methionine supplies for dairy cows fed maize silage based rations has been clearly demonstrated (Sloan 1992). Theoretically grass silage based rations are also deficient in methionine in most dietary situations. Expressed as a percentage of PDIE (protein digestible in the small intestine when energy is limiting microbial protein synthesis in the rumen) the metDI value for grass silage approximates 1.95 compared to 1.97 for maize silage.This trial was conducted, to verify, if in practice, methionine alone could limit milk protein secretion in dairy cows fed grass silage based rations.

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The effect of different groups of amino acids on rat mammary protein synthesis in vitro

Proceedings of the British Society of Animal Science ◽

10.1017/s1752756200002428 ◽

1999 ◽

Vol 1999 ◽

pp. 87-87

Author(s):

J.Alderson ◽

B.J. Bequette ◽

M.A. Lomax

Keyword(s):

Amino Acids ◽

Protein Synthesis ◽

Dairy Cows ◽

Protein Content ◽

Milk Protein ◽

Mammary Glands ◽

Milk Protein Content ◽

Milk Industry ◽

The Uk

The current pricing structure of the UK milk industry considers milk quality with higher premiums paid for milk protein content than for fat. Attempts to alter milk protein content by feeding extra protein(Bequette et al.,1998) or infusing amino acids(AA) in dairy cows has not always given consistent results. The present study is the first in a series where the objective is to use explants prepared from rat mammary glands to start identifying which AA may be (limiting) most important in regulating milk protein synthesis. Such information could be useful to identify specific AA which should be supplemented in the diet of the cow.

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Plasma free amino acids in high-yielding dairy cows: Is glutamine indispensible for milk protein synthesis?

Livestock Production Science ◽

10.1016/0301-6226(93)90220-c ◽

1993 ◽

Vol 35 (1-2) ◽

pp. 195

Keyword(s):

Amino Acids ◽

Protein Synthesis ◽

Dairy Cows ◽

Free Amino Acids ◽

Free Amino ◽

Milk Protein ◽

Plasma Free Amino Acids

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Regulation of Milk Protein Synthesis by Free and Peptide-Bound Amino Acids in Dairy Cows

Biology ◽

10.3390/biology10101044 ◽

2021 ◽

Vol 10 (10) ◽

pp. 1044

Author(s):

Miaomiao Zhou ◽

Lianbin Xu ◽

Feng-Qi Zhao ◽

Hongyun Liu

Keyword(s):

Amino Acids ◽

Protein Synthesis ◽

Mammary Gland ◽

Dairy Cows ◽

Milk Protein ◽

Utilization Efficiency ◽

Lactation Performance ◽

Protein Requirements ◽

Complex Biological Process ◽

Underlying Mechanisms

Milk protein (MP) synthesis in the mammary gland of dairy cows is a complex biological process. As the substrates for protein synthesis, amino acids (AAs) are the most important nutrients for milk synthesis. Free AAs (FAAs) are the main precursors of MP synthesis, and their supplies are supplemented by peptide-bound AAs (PBAAs) in the blood. Utilization of AAs in the mammary gland of dairy cows has attracted the great interest of researchers because of the goal of increasing MP yield. Supplying sufficient and balanced AAs is critical to improve MP concentration and yield in dairy cows. Great progress has been made in understanding limiting AAs and their requirements for MP synthesis in dairy cows. This review focuses on the effects of FAA and PBAA supply on MP synthesis and their underlying mechanisms. Advances in our knowledge in the field can help us to develop more accurate models to predict dietary protein requirements for dairy cows MP synthesis, which will ultimately improve the nitrogen utilization efficiency and lactation performance of dairy cows.

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Digestion of alfalfa and grass silages in sheep. 2. Digestion of protein in reticulorumen and intestines.

Netherlands Journal of Agricultural Science ◽

10.18174/njas.v36i4.16662 ◽

1988 ◽

Vol 36 (4) ◽

pp. 365-374

Author(s):

J. van Bruchem ◽

A.K. Kies ◽

R. Bremmers ◽

M.W. Bosch ◽

H. Boer ◽

...

Keyword(s):

Amino Acids ◽

Protein Synthesis ◽

Small Intestine ◽

Amino Acid ◽

Milk Protein ◽

Diaminopimelic Acid ◽

Microbial Protein ◽

Grass Silage ◽

Amino Acid Profiles ◽

Limiting Amino Acids

Wilted lucerne and grass silages were given to mature wethers. Estimates of degradability of proteins in the reticulorumen were lower with diaminopimelic acid (38-71%) than those based on amino acid profiles of dietary, microbial and duodenal proteins (64-87%). Microbial protein synthesis was related to extent of organic matter fermentation in the reticulorumen. Efficiency of protein synthesis was not different between silages. Apparent digestibility of protein and amino acids in the small intestine was lower for lucerne silage (54%) than for grass silage (60-63%), probably caused by a higher DM passage in the small intestine of lucerne silage. Relative to the amino acid profiles of milk protein and beef, histidine and methionine were the first limiting amino acids. (Abstract retrieved from CAB Abstracts by CABI’s permission)

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