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Effects of induced subacute ruminal acidosis on milk fat content and milk fatty acid profile
Author(s) -
Enjalbert F.,
Videau Y.,
Nicot M. C.,
TroegelerMeynadier A.
Publication year - 2008
Publication title -
journal of animal physiology and animal nutrition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.651
H-Index - 56
eISSN - 1439-0396
pISSN - 0931-2439
DOI - 10.1111/j.1439-0396.2007.00765.x
Subject(s) - fatty acid , rumen , food science , dry matter , chemistry , zoology , biology , biochemistry , fermentation
Summary Two lactating dairy cows fitted with a rumen cannula received successively diets containing 0%, 20%, 34% and again 0% of wheat on a dry matter basis. After 5, 10 and 11 days, ruminal pH was measured between 8:00 and 16:00 hours, and milk was analysed for fat content and fatty acid profile. Diets with 20% and 34% wheat induced a marginal and a severe subacute ruminal acidosis respectively. After 11 days, diets with wheat strongly reduced the milk yield and milk fat content, increased the proportions of C8:0 to C13:0 even‐ or odd‐chain fatty acids, C18:2 n‐6 and C18:3 n‐3 fatty acids but decreased the proportions of C18:0 and cis‐ 9 C18:1 fatty acids. Wheat also increased the proportions of trans‐ 5 to trans‐ 10 C18:1, the latter exhibiting a 10‐fold increase with 34% of wheat compared with value during the initial 0% wheat period. There was also an increase of trans‐ 10, cis‐ 12 C18:2 fatty acid and a decrease of trans‐ 11 to trans‐ 16 C18:1 fatty acids. The evolution during adaptation or after return to a 0% wheat diet was rapid for pH but much slower for the fatty acid profile. The mean ruminal pH was closely related to milk fat content, the proportion of odd‐chain fatty acids (linear relationship) and the ratio of trans‐ 10 C18:1/ trans‐ 11 C18:1 (nonlinear relationship). Such changes in fatty acid profile suggested a possible use for non‐invasive diagnosis of subacute ruminal acidosis.