An outbreak of mastitis caused by Staphylococcus aureus occurred in a commercial dairy goat herd during kidding season, resulting in fatal gangrenous mastitis in approximately 30% of the herd. S. aureus was recovered from milk, mammary tissue, and other organs in does subjected to necropsy. The S. aureus milk culture-positive rate among does in the hospital pen was 58.3%, while whole-herd milk cultures of clinically normal mature does identified S. aureus in 15.0% with an additional 15.0% positive for coagulase-negative Staphylococcus (CNS), yielding a total culture-positive rate of 30.0%. The prevalence of CNS in subclinical animals was consistent with previous reports from U.S. dairy goats; in contrast, S. aureus isolation rates substantially exceeded previously reported prevalences. Poor milking hygiene and milking machine dysfunction were identified as major factors contributing to the spread of the S. aureus from goat to goat. California Mastitis Test (CMT) scores were significantly higher in culture-positive does compared with culture-negative animals (p < 0.05), demonstrating the value of CMT as a practical on-farm tool for early treatment decision making. Interventions focused on addressing milking hygiene and milking machine maintenance, as well as segregation and vaccination of replacement females. S. aureus dropped to undetectable in the next two kidding seasons, whereas the CNS culture rates remained unchanged, suggesting other factors may be contributing to CNS infection. This case highlights the role of subclinical intramammary infection and milking practice factors in transmission and control of contagious mastitis pathogens like S. aureus.

Background: Transfusion with fresh frozen plasma (FFP) or hetastarch 6% (HES) is an option for managing decreased colloid oncotic pressure (COP) associated with hypoproteinemia. The effectiveness of HES compared to plasma has not been reported in calves and goats. Hypothesis: Hetastarch increases COP to levels similar to FFP. There will be no significant adverse clinicopathological changes after administration of HES. Animals: Seven healthy preweaned calves and 7 juvenile goats from university herds. Methods: Cohort, clinical trial in a two-way crossover design. Hetastarch and FFP were administered intravenously at 10 and 20 mL/kg, respectively, once. Plasma COP was measured re-transfusion, at 0, 1, 2, 4, 6, 12, 24, 36, 72 h, and 7 days after each transfusion. Coagulation variables were analyzed pre-transfusion, at 0, 24, and 72 h after transfusion. The effects of treatment and time on COP and coagulation variables were determined by multivariate analysis of variance. Results: Transfusion with FFP and HES increased the COP in calves and goats, with FFP increasing the COP to a greater magnitude in calves (least square mean difference of 1.6 vs. 1 mmHg; p = 0.03) but not in goats (least square mean difference of 3.0 vs. 3.0 mmHg; p = 0.99). There were no significant changes (p > 0.05) in coagulation variables detected after transfusion with FFP or HES. Conclusions and Clinical Importance: Hetastarch is an alternative colloid to FFP in calves and goats. Adverse changes were not observed in goats and calves after HES administration.