Indicators of undernutrition in cattle
Potential biochemical indicators of long-term undernutrition in cattle, which could be used objectively, reliably and routinely, were investigated by evaluating frequently analysed metabolites in cattle. In an initial study, a meta-regression of literature data for glucose, urea, non-esterified
fatty acids (NEFA) and β–hydroxybutyrate (BHB) against body condition score (BCS), body weight (BW) and its change (BWC) was conducted. The credible intervals of the gradients included zero for all regressions, showing that there were no significant relationships between any of
the blood metabolites and BCS, BW or BWC across the 13 included studies. In a second study, fresh field samples from nine herds of adequately-nourished suckler cows and stored samples from two herds of suckler cows, which had experienced severe undernutrition, were analysed for serum albumin,
total protein, urea, BHB, NEFA, creatinine, fructosamine and globulin. Positive regressions with BCS were obtained for albumin and creatinine, and a negative regression with fructosamine/albumin ratio. With the threshold for detecting undernutrition set at ≥10.75 μmol g−1,
the fructosamine/albumin ratio gave sensitivity and specificity of 100%. Therefore, it is probably necessary to combine several blood measures to obtain a valid assessment of the nutritional state of ruminants, and we advise against the use of a single plasma metabolite concentration in assessing
the nutritional state and welfare of individual cows.