South American camelid sperm characteristics are poorly known compared with those of other domestic animals. The long-term duration of ejaculation makes difficult to gather all the seminal fluid, implying possible ejaculation portion losses. Thus, the aim of this research was to evaluate the characteristics of the morphology and morphometry of the spermatozoa change during ejaculation. The morphometric characterization was tested on nine specimens of the Lanuda breed, using a special artificial vagina. In five of the animals, a fractioning of the ejaculate was performed by taking samples every 5 min. for a total of 20 min. Air-dried seminal smears were stained with Hemacolor and mounted permanently with Eukitt. Morphometric analysis was carried out with the morphometry module of the ISAS(®) CASA system. Almost 350 cells were analysed per sample, with a total number of 3207 spermatozoa. Mean values were given as follows: length: 5.51 μm; width: 3.38 μm; area: 17.75 μm(2) ; perimeter: 14.8 μm; ellipticity: 0.24; elongation: 0.56; rugosity: 0.87; regularity: 1.07; and shape factor: 1.41. Different animals showed differences in their morphometric values. When we compared the values from different fractions, only two samples showed differences in morphometric parameter values and four samples showed differences in shape parameters. Multivariate analysis allowed the size classification of the cells into three classes and five classes of shapes. The distribution of classes among fractions showed no differences. Despite the individual morphometric differences observed in some fractions, the characteristics of the sperm head morphometry can be considered constant along the ejaculatory period in the llama.

The Andean puma (Puma concolor) has not been widely studied, particularly in reference to its semen characteristics. The aim of the present study was to define the morphometry of puma sperm heads and classify their subpopulations by cluster analysis. Samples were recovered postmortem from two epididymides from one animal and prepared for morphological observation after staining with the Hemacolor kit. Morphometric data were obtained from 581 spermatozoa using a CASA-Morph system, rendering 13 morphometric parameters. The principal component (PC) analysis was performed followed by cluster analysis for the establishment of subpopulations. Two PC components were obtained, the first related to size and the second to shape. Three subpopulations were observed, corresponding to elongated and intermediate-size sperm heads and acrosomes, to large heads with large acrosomes, and to small heads with short acrosomes. In conclusion, puma spermatozoa showed no uniform sperm morphology but three clear subpopulations. These results should be used for future work in the establishment of an adequate germplasm bank of this species.

Sperm morphometry is a part of the semen analysis based on CASA technology and has shown a big role in the

Semen analysis is a key factor when determining the fertility ability in males. South American camelids, and in particular the alpaca, have been studied very little when compared with other farm animals. The aim of this work was to perform the kinematic characterization of alpaca spermatozoa collected directly from the deferent duct by using CASA-Mot (Computer Assisted Semen Analysis for Motility) technology. Samples were obtained every three days throughout the reproductive season during two periods and with a break of seven days in the middle. During both periods, the quality of the sample's motility and kinematics increased over the first two days and then subsequently decreased. This pattern was similar in all animals. It was concluded that the introduction of resting times can be useful to improve sperm quality for artificial insemination purposes in natural conditions.

Artificial insemination (AI) with cryopreserved semen is used to reproduce genetically valuable animals and to improve domestic species productivity. In South American camelids (SACs), different diluents have been used, several cryoprotectants have been tried at different concentrations and diverse cooling, and freezing rates have been tested (Carretero et al.,