A morphological classification of sperm defects in the ostrich (Struthio camelus)

Abstract

Commercial ostrich farming is constrained by the absence of a formal animal recordingand evaluation scheme as well as by current farming practices. Artificial insemination mayhave an important role in overcoming these limitations, but requires a thorough knowl-edge of sperm morphology. Although the morphological characteristics of normal ostrichsperm have been documented, little information is available on the incidence and struc-tural peculiarities of defective sperm in this species. Semen smears were prepared fromthe ejaculates of five ostriches (Struthio camelus), stained and evaluated. Defects wereobserved in 17% of sperm studied. Tail defects constituted the most common anomaly.Various forms of bending were the main tail defect, ranging from gentle to acute bends ofthe principal piece, Dag-like coiling at the head base, sharp reflexes of the midpiece as wellas coiling of the endpiece. In contrast, head defects were comparatively low in frequency,with macrocephalic sperm being the defect most frequently observed in this region. Bent,microcephalic, acephalic and round sperm heads were also noted but were few in num-ber. Cytoplasmic droplets occurred frequently in the fixed smears, either associated withthe sperm or as free-lying droplets. A small percentage of sperm with multiple defectswas recorded. The incidence of morphologically normal sperm in ostrich semen comparedfavorably with that reported in emu semen, another commercially farmed ratite. However,the range of defects differed appreciably between the two species. Sperm tail anomalieswere the most frequent category in the ostrich, whereas head defects comprised the maingrouping in the emu.