Rumen Health Technical Guide

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Dimensions of Acidosis (Clinical & Subclinical)


Intensive farming practices require a high plane of nutrition, which typically includes high levels of fermentable carbohydrates which can put the animal at risk for developing metabolic disorders, in particular, challenges to rumen stability and sub acute acidosis.

Different degrees of acidosis appear when the fermentation profile of the rumen is unbalanced by high levels of lactic acid or butyric acid.26ReferenceView allKrause K.M., Oetze G. R. 2006.
27ReferenceView allEnemark J. M. D. 2008.
28ReferenceView allGonzález L. A., Manteca X., Calsamiglia S., Schwartzkopf-Genswein K.S., Ferret A. 2012.
29ReferenceView allCastillo-Lopez E., Wiese B. I., Hendrick S., McKinnon J. J., McAllister T. A., Beauchemin K. A. and Penner G. B. 2014.

Adapted from Nocek. 12ReferenceView allNocek J. E. 1997.

 

Sub Acute Ruminal Acidosis (SARA)

  • More common, results from excessive volatile fatty acidGlossaryView allVolatile Fatty Acid (VFAGlossaryView allVolatile Fatty Acid (VFA)
    The microbial ecosystem in the rumen ferments carbohydrates into VFAs. These products are absorbed though the rumen wall into the blood and used like energy source for the animal. The three main VFAs are acetic acid, butyric acid and propanoic acid.
    )

    The microbial ecosystem in the rumen ferments carbohydrates into VFAs. These products are absorbed though the rumen wall into the blood and used like energy source for the animal. The three main VFAs are acetic acid, butyric acid and propanoic acid.
    (VFA) production that exceeds the ability of the rumen to neutralize and it exceeds the absorption capacity of the ruminal papillae.
  • Rumen pH drops below 5.8 and remains bellow this threshold for three or more hours within a 24-hour period.
  • Animals generally have mild diarrhea, lowered dry matter intake and laminitis.
  • Can develop into acute acidosis if the pH is never able to recover.

Acute Ruminal Acidosis

  • Less common, more severe, usually occurs when pH falls below 5.5.
  • Usually associated to a drastic diet change.
  • Animals have depressed productivity, go of feed, have elevated heart-rate, diarrhea and may die.
  • Severe lactic acidosis may cause irregular feeding behavior and gorging, which creates more spikes of acid production.

 

指標とリスクの特徴

主要因
table-arrow-down動物の生産成績- 肉牛において日増体量と飼料効率が低下するのは、ルーメン発酵の停滞に原因がある可能性があります。
- 泌乳牛において乳量と乳脂肪、乳脂肪/乳タンパク質比率が低下するのは、ルーメン発酵の停滞に原因がある可能性があります。17ReferenceView allBritt J. S., Thomas R. C., Speer N. C., and Hall M. B. 2003.
18ReferenceView allAllen M. S. 1997.
19ReferenceView allSauvant D. and Peyraud J. L. 2010.
table-arrow-down反芻活動
アシドーシスによってルーメンの運動性が低下する
と、反芻活動が抑制される場合があります。18ReferenceView allAllen M. S. 1997.
30ReferenceView allGrant R. J., Colenbrander V.F. and Mertens D. R. 1990.
table-arrow-down歩様動物の跛行は、ルーメン内のヒスタミンとエンドトキシン量が高いことを示しています12ReferenceView allNocek J. E. 1997.
table-arrow-downルーメンフィル
ルーメンの充満度が低いことは、採食量が低下して、ルーメン効率が低下していることを示しています。22ReferenceView allZaaijer D. and Noordhuizen J. P. T. M. 2003.
table-arrow-down糞の固さ
下痢の発生は、バランスの悪い飼料によって消化管内での通過速度と下部消化管での発酵が増加し、ルーメン効率が低下していることを示しています。20ReferenceView allHall M. B. 2002.
21ReferenceView allHutjens M. F. 2010
22ReferenceView allZaaijer D. and Noordhuizen J. P. T. M. 2003.
table-arrow-down尾部周辺の清潔さバランスの悪い飼料によって消化管内での通過速度が増加し、消化率が低下すると、動物の尾部周辺の汚れに繋がります。
table-arrow-up未消化穀物ルーメン効率が悪く、加工済みの穀物が糞中に未消化の状態で見られる時には、飼料のバランスが悪いか飼料の消化率が低いために、飼料の通過速度が速くなっている可能性があります。 20ReferenceView allHall M. B. 2002.
table-arrow-up暑熱ストレス暑熱ストレス (気温と湿度)が増加すると、下に記載する理由から、アシドーシスと飼料消化率低下のリ
スクが高まります。
>採食行動に負の影響が見られます: 明け方や夕方の涼しい時間に採食することを好みます。
> 乾物摂取量が低下します: 牛は易発酵性炭水化物を選び食いし、粗飼料の摂取割合を低下させます。
> 口を開けた呼吸や流涎によって唾液をロスし、ルーメンに流入するバッファーの量を減少させます。31ReferenceView allBurgos Zimbelman Rosemarie and Collier Robert J. 2011.
rumen-wall-healthy-photo-lallemand-forward
Healthy rumen papillae
rumen-wall-damaged-photo-lallemand-forward
Rumen wall damaged by acidosis

Financial impacts

The financial impact of rumen acidosis is staggering.

In lactating dairy cows, economic loss can be attributed to: lower milk fat content (-0.76%), depressed milk production (-10%), poor reproductive performance and increased risk of secondary metabolic disorders. One study estimates the overall impact to the U.S. dairy industry is between $500 million and $1 billion per year.32ReferenceView allKrause K.M., Oetzel G.R. 2006.

Another study estimates sub acute acidosis costs $34,750 per 100 cows.33ReferenceView allZebelli Q. et Ametaj B. N. 2009.

In growing and finishing beef cattle,  economic loss can be attributed to: lower growth rate (-78g/hd/d; -0.17 lbs/hd/d),  impaired feed-to-gain conversion, lower meat grades, and increased risk of secondary metabolic health events.34ReferenceView allThompson P. N., Hentzen A., Schultheiss W. A. 2006.