Metabolic profiles of non-lactating, pregnant heifers during transitioning from kale to swedes in Southland, New Zealand

摘要

During winter 2014, a study was conducted in non-lactating pregnant dairy heifers to monitor changes in liver enzymes during a six-week period following a diet change from kale to swedes. Blood samples were collected from 20 cows on Days 0, 4, 7, 14,28, and 42 after transitioning. Changes were recorded for most blood metabolites, in response to the change from kale to swedes, indicating potential liver inflammation or hepatic cell stress damage. On days four and seven, 6 and 8% of animals had lowerthan normal concentrations of AST, respectively. Elevated concentrations of GGT and GLDH, relative to Day 0, were recorded on Day 7 and 14 in individual cows. NEFA concentrations peaked on Day 4, possibly indicating a decrease in feed intake during the initial transitioning process. Up to 40 percent of the herd exhibited metabolic changes during the transition period. Although the concentration of some metabolites were above the normal range for individual animals between days 4 and 14, they had decreased to within the normal range by day 28, indicating that cows had become adapted to the new diet. Results suggest that, even with good practice, individual animals within a herd are at risk of liver stress when transitioning onto swedes.