Effect of intramammary lipopolysaccharide infusion on milk pH of uninfused udder in goat.

The change in milk composition in response to intramammary infusion of Escherichia coli lipopolysaccharide (LPS) was investigated. Four clinically healthy goats were infused with LPS (100 µg) by intramammary administration to the left udder. Clinical manifestations (rectal temperature and physical activity), selected blood parameters (pH and white blood cell count) and milk compositions (somatic cell count and pH) were evaluated at 0 hr (just before challenge) and at multiple time points over the first 24 hr post-challenge. After intramammary LPS challenge, the pH of milk from both udders increased. Thus, this study revealed that LPS-induced mastitis in goat can result in increased pH in milk from the unchallenged (contralateral) udder.

Blood ionized calcium levels and acute-phase blood glucose kinetics in goats after intramammary infusion of lipopolysaccharide.

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.