RESUMEN
Sperm morphometry is the tool that confers objectivity to the morphological evaluation by accurately measuring the dimensions of the gamete and its structures. Thus, the aim of the study was to perform a morphometric characterization of the domestic cat sperm. Therefore, sperm samples were collected from twenty pairs of epididymis in a TRIS extender at 37ºC. An aliquot of the sample was used to make a smear with Rose Bengal solution, and afterwards, the morphology and morphometry were analysed. In the morphology, were quantified the percentage of normal sperm cells, morphological changes of head, midpiece and tail. In morphometry, each normal sperm cell was measured for length, width, area and perimeter of head and midpiece, tail length and total length. The parameters ellipticity, elongation, regularity and rugosity were also determined. The percentage of normal sperm was 67.21%. Of the abnormalities, the curled/folded tail, followed by the curved midpiece, abnormal shaped head and detached head were the most quantified. The sperm head presented 5.56 ± 0.01 µm and 3.10 ± 0.01 µm of length and width, respectively. The head area was 16.94 ± 0.05 µm2 , while the perimeter was 16.16 ± 0.03 µm. In the derived parameters, the values were as follows: ellipticity of 1.81 ± 0.00; elongation of 21.39 ± 0.12; regularity of 0.81 ± 0.00; and rugosity of 0.14 ± 0.00. The midpiece presented length and width of 7.96 ± 0.01 µm and 0.76 ± 0.01 µm, respectively. The mean length of the sperm tail was 45.12 ± 0.06 µm, and the total cell size was 58.67 ± 0.06 µm. Thus, it was concluded that the cat sperm is an elongated cell, with high rugosity and regularity. The spermatic tail represents more than ¾ of the total length of the cell and the midpiece exceeds the length of the head.