Oral and Poster Abstracts

improve management practices to minimize subclinical disease in
transition cows and maximize profitability.
Key words: metabolic disease, transition cows, subclinical ketosis,
negative energy balance, Lima Peru
73 Evaluation of three Laboratory Methods Measuring NEFA in
Cow’s Blood
T. Gaal, P. Ribiczey
Szent István University Faculty of Veterinary Science, Department of
Internal Medicine, Budapest, Hungary
Non esterified fatty acids (NEFA) in the blood are good markers of
negative energy balance (NEB) in dairy cows. There are several
laboratory methods to assess NEFA concentration. One method is
based on a colorimetric, non-enzymatic technique at room temperature
(Duncombe, 1964), the other one applies colorimetric, enzymatic
determination at 37 °C (Matsubara et al., 1983). Recently a portable
photometer appeared on the market (DVM-NEFA ® ) using a
colorimetric technique for NEFA measurement at room temperature.
As laboratory methods need a well-equipped laboratory with skilled
personnel, introduction of a cow-side test is more than welcome.
However, widely used NEFA reference values were established by the
laboratory methods, therefore critical evaluation of DVM-NEFA is
recommended. The goal of this study was to compare NEFA results
determined with 3 methods. On a herd of 900 HF dairy cows blood
samples were collected from dry cows (n=17) and fresh cows (n= 14).
Blood serum NEFA was measured immediately by 3 methods. For the
non-enzymatic method commercial chemicals were used while for the
enzymatic method a Randox NEFA test kit was applied on an
automatic chemistry analyzer. Results were analyzed by t-test and
regression analysis. Pre-partum NEFA values determined by DVM-
NEFA, non-enzymatic and enzymatic methods were 0.258+0.200,
0.105+0.090 and 0.093+0.088 mmol/L, respectively. Post-partum
these were 0.706+0.327, 0.300+0.146 and 0.293+0.179 mmol/L. Prepartum
NEFA was lower than post-partum with all methods (P