Short communicationDaily rhythms of acute phase proteins in cattle under different natural environmental conditions

This study was conducted to assess the pattern of daily rhythms of acute phase proteins (APPs), including haptoglobin (Hp) and serum amyloid A (SAA), and the pattern of daily rhythms of fibrinogen (Fb), white blood cell counts (WBC) and packed cell volume (PCV) in Holstein Friesian and Modicana dairy cattle. Blood samples were collected every 3 h over a 48 h period from six Holstein Friesian and six Modicana dairy cattle during two different periods: January and July.Hp was higher in Modicana cattle than Holstein Friesian cattle in both periods, and it was lower in July than January in both breeds. All parameters, except PCV, showed daily rhythmicity in both breeds, during the two periods. In Holstein Friesian cattle, Hp and WBC acrophases were postponed by about 2 h during July with respect to January and with respect to Modicana cattle in the same period. A high correlation between individual values of WBC and of APPs was observed. The exact mechanism that causes this variation is not clear. More studies are necessary to understand the amount of these variations and to provide diagnostic and prognostic information useful for the animal welfare control.