Reproductive characteristics of female lesser mouse deers (Tragulus javanicus) based on fecal progestagens and breeding records

Information about breeding and the reproductive biology of mouse deer is limited in the wild and captivity. No reports on reproductive endocrinology are available. The objective of the present study was to observe the reproductive biology based on breeding records, to validate the utility of the non-invasive endocrine monitoring technique using feces of the female lesser mouse deer (Tragulus javanicus), and thus to clarify the reproductive physiology. Breeding records from 2 females were investigated and the fecal progestagen profile was monitored in captivity. Fecal progestagens were extracted using methanol and measured by enzyme immunoassay. From the breeding records, many births occurred in May (spring) and November–December (winter); however, fecal progestagen profile showed cyclical changes throughout the year in a female mouse deer. Most mounting and mating behaviors were observed 2–3 days after the peak of progestagen concentration during luteal phase. The ovarian cycle length based on the fecal progestagen profile averaged 14.5 ± 0.3 days. The fecal progestagen concentration remained high during pregnancy. Fecal progestagen monitoring is useful for evaluating ovarian activity and pregnancy in the lesser mouse deer.