Med. Weter. 69 (6), 363-368, 2013

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K.A. Białoń, R. Skrzypek
An evaluation of the possibilities for the use of blood acetone concentration, body weight changes and milk and reproduction performances as indicators of dairy cow adaptation to metabolic stress during the initial period of lactation
The study was conducted on 124 Polish Holstein-Friesian primiparous cows of the black-white variety. The aim was to determine the relationship between the following indicators of adaptation to metabolic stress occurring in dairy cows in the early lactation stage due to negative energy balance: acetone concentration in blood (AcC) on days 5, 30, 60 and 90 after calving; body weight changes between days 5 – 60 after calving (BWC); milk yield (MY), fat content (FC) and protein content (PC) in milk, fat to protein ratio in milk (FPR) during the first 100 days of lactation; calving to conception interval (CC) and the number of AI services per conception (NSC). The data were analyzed using logistic regression. It was found that AcC positively influenced BWC, FC and FPR (OR>1.0), and negatively PC (OR<1.0), while the influence on MY was variable on subsequent dates of the examination, i.e. positive on days 5 and 30, and negative on days 60 and 90. In terms of the particular dates of AcC examinations, particularly large relationships were noted on the 60th day after calving. It was also demonstrated that the relationship of AcC was reversible in the case of FC, and especially PC and FPR. With regards to fertility parameters, AcC and FPR influenced them to the highest degree on the 90th day after calving (OR from 6.4 to 8.9), and so did PC (OR between 0.3-0.4) and FC (OR between 1.1-1.9). Concluding, among the tested traits, FPR is of the highest diagnostic value as an early indicator of metabolic stress, generally observed in dairy cows during the early lactation stage. A similar diagnostic value may be attributed to AcC; however, the possibilities of applying this parameter in practice are considerably lower.
Key words: dairy cows, early lactation, metabolic stress, blood acetone, fat to protein ratio