We evaluated the uterus and ovaries of owl monkeys (Aotus azarai infulatus) via gynecological ultrasound examination. We evaluated the subjects in 2 different time periods. The first period (P1) was characterized by the absence of mating, with daily examinations, during 4 mo (n=10). At the end of P1, we paired the subjects for 30 d, but without ultrasonographic evaluation. The second period (P2) was characterized by the presence of mating, with examinations once a week, during 7 consecutive months (n=9). We evaluated the uterus and ovaries in sagittal and transverse scans, using a 5-12 MHz linear array probe. The uterine volume (UV) was directly proportional to the number of previous parturitions. The right ovary volume (RtOV) is greater than the left (LtOV) in P1 and P2. There is a positive correlation (p<0.05) between the females' mass, RtOV (r=0.28) and LtOV (r=0.16).

Significant differences were observed in hematocrit and hemoglobin values between males and females. The levels of alkaline phosphatase in the tissues were significantly influenced by age. There was also a sex influence on blood urea nitrogen and creatinine levels. The results show that some hematological and clinical chemistry parameters in owl monkeys may be influenced by sex and age.

Research on Neotropical primates' reproduction is necessary due to the lack of available information and the increasing threat to these species. Callimico goeldii is listed as Vulnerable on the IUCN Red List of Threatened Species. This study aimed to test rectal electrostimulation for semen collection and evaluate seminal characteristics. Therefore, semen from 6 captive Goeldi's monkeys was collected and, for the first time, seminal characteristics are described. Coagulum formation was noted in all ejaculates, and we obtained partial or complete liquefaction of the samples. Results were (means ± SD): volume = 26.9 ± 11.87 μL; pH = 7.61 ± 0.28; concentration = 143.18 ± 174.96 × 10⁶ spermatozoa/mL; total sperm motility = 83.33 ± 5.16%; linear progressive motility = 46 ± 24.08%; plasma membrane integrity = 36.38 ± 16.11%; acrosome integrity using fast-green/bengal-rose staining = 63.41 ± 11.72%, and kit Spermac® = 69.36 ± 11.81%; abnormal sperm = 72.5 ± 17.7%, with 16.2 ± 7.7% major defects and 56.3 ± 10% minor defects; sperm with high mitochondrial activity class I = 16.45 ± 22.25%. Rectal electrostimulation was an efficient method for semen collection in this species. Investigations are required to improve semen collection and handling, including cryopreservation methods.

The common marmoset is an important Neotropical primate for biomedical research. With the intention of providing pelvimetric values that allow the selection of animals with better characteristics for reproduction, we studied the X-ray of the pelvis, in ventro-dorsal projection of 12 adult animals, six males and six females, belonging to the National Center of Primates -CENP. The measurements were made to right diagonal diameters (RDD), left diagonal diameter (LDD), bi-iliac middle diameter (BIMD), bi-iliac upper diameter (BIUD), bi-iliac lower diameter (BILD), sacrum-pubic diameter (SPD), and the input area of the pelvis (IAP), which were compared in relation to sex and bodily correlated with the biometrics. The results of the means and standard deviations regarding pelvimetry (cm) were: for the RDD in males of 1.91±0.14 and in the females of 2.05±0.08; LDD in males of 1.85±0.16 and in females of 2.03± 0.08; BIMD in males of 1.46±0.12 and in the females of 1.5±0; BIUD showed in males 1.3±0.1 and in females of 1.3±0.06; BILD in males of 1.35±0.15 and in females of 1.25±0.08; SPD in males of 1.68±0.09 and in females of 1.93±0.13; IAP in males of 1.9±0.26 and in the females of 2.23±0.13. It was concluded that the pelvis of Callithrix jacchus could be classified as dolicopelvic type, there is sexual dimorphism in relation to the pelvis of adult animals and that the bodily measurements have low positive correlation with pelvic measurements.Keywords: radiology, pelvis, primates RESUMO O sagui-de-tufo-branco se destaca como um importante primata neotropical para as pesquisas biomédicas. Com o intuito de fornecer valores pelvimétricos que permitam a seleção de animais com melhores características para a reprodução, estudaram-se radiografias da pelve, em projeção ventrodorsal, de 12 animais, sendo seis machos e seis fêmeas, adultos, pertencentes ao Centro Nacional de Primatas -CENP. As mensurações realizadas foram referentes aos diâmetros diagonal direito (DDD), diagonal esquerdo (DDE), bi-ilíaco médio (DBIM), bi-ilíaco superior (DBIS), bi-ilíaco inferior (DBII), sacropúbico (DSP), além da área de entrada da pelve (AEP), os quais foram comparados em