Pen-floor moisture and sporulated Eimeria oocyst accumulation are associated with subsequent oocyst shedding in Boer-cross goat kids: a 12-week longitudinal study

Abstract

Pen-floor moisture may influence the development and persistence of environmental Eimeria oocysts, but its temporal relationship with subsequent infection in goat kids remains unclear. This 12-week longitudinal study followed 96 Boer-cross goat kids housed in 16 separate pens. Pen-floor moisture and environmental oocyst contamination were assessed weekly, individual faecal oocyst per gram (OPG) was determined every two weeks, and faecal consistency was scored weekly. Environmental contamination was expressed as total and sporulated oocysts per gram of dry matter. Median total oocyst burden increased from 1,525 oocysts/g DM at moisture levels below 25% to 6,728 oocysts/g DM at moisture levels of at least 45%, while median sporulated burden increased from 210 to 3,364 oocysts/g DM. Each 10-percentage-point increase in moisture was associated with 1.59- and 3.07-fold increases in total and sporulated environmental burdens, respectively. In separate two-week lag models, higher moisture and greater sporulated burden were associated with 1.38- and 1.22-fold increases in subsequent fecal OPG, respectively. When both exposures were included simultaneously, moisture was no longer independently associated with subsequent OPG, whereas each doubling of sporulated burden remained associated with a 1.26-fold increase. Neither exposure was significantly associated with subsequent diarrhoea. These findings indicate that moisture provides an environmental condition favouring oocyst accumulation and sporulation, whereas sporulated oocyst burden represents a more immediate indicator of subsequent infection pressure. Maintaining dry pen floors and removing faecal material regularly may help reduce environmental exposure