The aim of this study was to determine the blood ionized calcium (Ca) levels and acute-phase blood glucose kinetics in goats with mastitis induced by an intramammary challenge of lipopolysaccharide (LPS). Five goats were subjected to intramammary challenge of either LPS (10 µg) or saline (control). Some clinical manifestations (rectal temperature, pulse rate, respiration rate, ruminal motility, physical activity, and dehydration) were observed, and blood was collected for the measurement of several parameters [ionized and total Ca levels, blood glucose level, pH, and white blood count (WBC)] at 0 (just before challenge), 1–4, 6, 8, 12 and 24 hr post-challenge in both the LPS and control phases. Milk was collected at 0 (just before challenge), 4, 8, 12 and 24 hr post-challenge to measure the somatic cell count (SCC) and N-acetyl-beta-D-glucosaminidase (NAGase) activity. In the LPS phase, increased rectal temperature, significantly decreased ionized Ca and total Ca levels and WBCs were observed compared with those at 0 hr, although there were no differences in all parameters between phases. LPS infusion significantly increased SCCs in milk and NAGase activity. The present results demonstrated that, during the acute phase of mastitis induced by intramammary challenge by LPS at a concentration sufficient to cause general symptoms in goats, a decreased blood ionized Ca level occurs, but not hypoglycemia.