BLOOD PARAMETERS DURING LACTATION AND DRY PERIOD IN SARDA SHEEP BREED V. Carcangiu, G.M. Vacca, M.C. Mura, M.L. Dettori, M. Pazzola, M. Fiori, P.P. Bini Dipartimento di Biologia Animale Università degli Studi di Sassari,, Via Vienna 2, 07100 - Sassari ABSTRACT The aim of this research was to evaluate the state of some haematochemical parameters in dry and lactating Sarda sheep breed. Twenty lactating sheep (Group A) and twenty dry sheep (Group B) were selected for this study; all the sheep were pluriparous and non-pregnant. Blood samples were collected from each animal of Group A on days 7 th and 30 th of the lactation period, and from each animal of Group B on day 60 th of the dry period. Plasma levels of NEFA, glucose, triglycerides, total cholesterol, total proteins, albumin, urea, Ca, P, Mg, Na and K were determined. Data were submitted to statistical analysis. As regards Group A, the plasmatic concentration of NEFA, glucose and triglycerides were higher on day 7 th (P<0.01) than those determined on day 30 th . As regards the comparison between the two groups, lactating sheep showed in both the samples plasmatic levels of NEFA (P<0.01), glucose (P<0.01), triglycerides (P<0.01) and urea (P<0.05) higher than those recorded in dry sheep. The concentrations of Na and K in Group A were lower on day 7 th than those recorded on day 30 th . In conclusion, the results indicate that the patterns of the parameters of the two groups is clearly affected by the different metabolic engagement that is necessary to satisfy udder requirements for milk production. INTRODUCTION Bodily metabolism undergoes several adaptations linked to the physiological phases. In fact in certain periods animal organism is submitted to an intense work to provide nutrients to determinate organs, like during lactation, while in other periods organism store the energy coming from food, as in the dry period. Those metabolic adaptation principally are linked to several hormones effect who causes a major or minor activity of some organs respect to others (Barman e Currie, 1980). During lactation undoubtedly GH, insulin, T3 and T4 are the hormones who determines the major effect on metabolism regulation (Hatfield et al., 1999). Exactly, lactating ruminants shows high GH levels while thyroid hormones and insulin levels are low (Bini et al., 1997; Head et al., 1993). This hormonal equilibrium drive to a fat mobilization and to a lower utilization of glucose from tissues, favouring the course of these elements to mammary gland for milk production (Carcangiu et al., 1998). In fact, during the first lactation moment, the animal is usually in negative energy balance because organism mobilizes bodily reserves in the form of NEFA to afford mammary gland requirement (Peel and Barman, 1987). Besides, low insulin haematic levels in addition to a lower fat synthesis cause a low tissues sensibility to glucose, leaving then this hexose available for making lactose (Regnault et al., 2004). Mineral 109