Preliminary Anatomical, Histological, and Histochemical Study of the Orbital Gland Complex in Kirk's Dik-Dik (Madoqua kirkii) and Red Forest Duiker (Cephalophorus natalensis).

The orbital glands are part of the ocular surface protective system, but their morphology and secretory profiles remain poorly documented in small wild bovids. This preliminary descriptive study examined nine young animals: four Kirk's dik-diks (Madoqua kirkii) and five red forest duikers (Cephalophorus natalensis). All animals underwent gross anatomical examination, and bilateral Harderian glands (HGs), lacrimal glands (LGs), and superficial glands of the third eyelid (SGTE) were examined histologically, histometrically, and histochemically. No inferential statistical comparisons between species were performed. In both groups, the HG was located medioventrally, the LG dorsolaterally, and the SGTE medially near the third eyelid. The glands showed compound tubuloacinar or predominantly acinar organization. Descriptive variation involved capsule thickness, septal development, lobular arrangement, secretory epithelial appearance, and plasma cell and lymphocyte distribution. Histochemical reactions demonstrated mixed secretory profiles containing neutral glycoconjugates and acidic mucosubstances consistent with sulfated and/or carboxylated components. Their relative proportions varied among glands and between groups. These findings provide preliminary anatomical and microscopic reference data for rarely examined wild bovids. Because of the small sample sizes, the observations should not be interpreted as definitive species-level differences.