6,502
edits
Changes
Jump to navigation
Jump to search
Subacute Rumenal Acidosis (view source)
Revision as of 20:09, 26 August 2010
, 20:09, 26 August 2010→Description
==Description==
==Description==
SARA is increasingtly being seen as a major nutritional
problem affecting dairy cows (Nordlund 2001). It is
insidious and, in many cases is never recognised or
diagnosed. let alone prevented. It is a group problem and
is best described as a fermentative disorder character-ised
bv a number of the g)rOup members having suboptimal
ruIllenl pH values. The deflinitioni applied in the USA is at
least 30 per cent of animials having rumen pH values of
5 5 or less when saimipled by ruIlmenlocentesis (Nordlund
2001). However, the author su,(ests that, under UK conditions,
a more sensitive threshold mnay be pH <5 7. This
is based on1 production anld intake responses seen after
dietary intervention in herds diag,nosed as suffering from
SARA using this threshold.
The increase in individual cow milk yields in the last 20 years has meant that the energy requirements for lactation have increased dramatically. In order to meet these increased energy demands and avoid prolonged negative energy balance in early lactation, the energy density of the ration has increased with the used of high levels of concentrated feeding/maize silage. These contain increased quantitites of rapidly fermentable carbohydrates that result in acid production in the rumen and a consequent fall in rumen PH below the optimum range of 6-7.
The increase in individual cow milk yields in the last 20 years has meant that the energy requirements for lactation have increased dramatically. In order to meet these increased energy demands and avoid prolonged negative energy balance in early lactation, the energy density of the ration has increased with the used of high levels of concentrated feeding/maize silage. These contain increased quantitites of rapidly fermentable carbohydrates that result in acid production in the rumen and a consequent fall in rumen PH below the optimum range of 6-7.