Factors affecting the shape of the lactation curve in Reggiana cattle

Reggiana is a local breed of cattle, reared in Northern Italy, with a low population size (916 milk recorded cows during 2001). The breed is appreciated because of milk composition characteristics for transformation, particularly for colloidal Ca and P content, rheological properties and k-CASB gene frequency (Mariani et al., 1998).Mean productive levels are 5401 kg milk, 3.51% fat, 3.38% protein (AIA, 2001). The breed is selected mainly for protein yield (kg), but literature about lactation curve is not available. Objectives of the research are to describe the lactation curve of Reggiana cattle by applying the Wood model and to evaluate some factors affecting its shape.