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The giant anteater (superorder Xenarthra) is listed as Vulnerable by the International Union for Conservation of Nature (IUCN) and a low reproductive rate is considered one of the factors contributing to population decline of the species. Nevertheless, little is known on reproductive features in male giant anteaters and, in this regard, microscopic testis morphology and spermatogenesis were studied in roadkill specimens in Brazil. Characteristics of germ cell populations resembled descriptions in other eutherian mammals including other xenarthran species. Furthermore, eight stages of the seminiferous epithelium cycle could be defined. The proposed staging system offers baseline data for assessing impairments or seasonal changes in spermatogenesis and thus allows future studies on reproductive health and reproductive seasonality in male giant anteaters.

This study aimed to evaluate the use of the Improvac® vaccine to avoid heat and pregnancies in queens and fertility in males during the breeding season. Twenty-eight intact animals were divided into treated males (G1, n = 7), treated females (G2, n = 18), and untreated males (G3, n = 3) that were untamed and could not be captured for immunization. In cats from the G1 group, the testicular volume (337.35 ± 95.74 mm 3 ) and testosterone concentration (1.31 ± 0.49 ng/mL) reached the lowest value 16 weeks after the first vaccination. At week 40, all queens exhibited both estrus cytology and estrus behavior, with serum estrogen (38.5 ± 1.93 pg/mL) and progesterone (0.5 ng/mL) concentrations within the physiological range for the phase. Eleven queens received a third dose of the vaccine at week 40, and none became pregnant by week 64. The remaining queens (n = 7) did not receive the third dose of the vaccine and became pregnant by week 44. In cats from the G1 and G2 groups, the hematologic parameters were within the physiological range for the species. The results of this study indicate that the Improvac® vaccine is safe and effective in the short to medium term in preventing cat reproduction., Competing Interests: Declaration of interest statement The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this article., (Copyright © 2025 Elsevier Inc. All rights reserved.)

The effects of Trypanosoma brucei infection on testicular morphology and function and the changes associated with treatment of infected dogs with diminazene aceturate were studied using fifteen Nigerian adult male dogs. The dogs were randomly assigned into three groups A, B and C consisting of five dogs each. Groups A and B were infected with 1 × 10(6) trypanosomes and group C was the uninfected control. Following infection, parasitaemia levels were monitored daily whereas the rectal temperature, body weight, packed cell volume, scrotal circumference and serum testosterone levels were monitored weekly. At parasitaemia peak, dogs in group A were orchidectomised while dogs in group B were treated with 7.0mg/kg body weight of diminazene aceturate (DA). Dogs in groups B and C were later orchidectomised on day 73 of the experiment. The harvested testes and epididymides were weighed and the epididymal sperm reserves of all the dogs determined. Also the sperm quality (mass activity, sperm motility and sperm morphology) were determined. The testes were sectioned after processing and studied histomorphologically. Acute trypanosomosis was observed following infection. The low serum testosterone levels observed from day 14 post infection (pi) gradually improved following treatment. Testicular weight, epididymal weight and sperm quality were significantly low (p<0.05) in the infected dogs when compared to the control group but gradually improved following treatment. Histomorphological studies revealed testicular degeneration characterized by depopulation of seminiferous tubules and depletion of spermatogenic cells in dogs of group A whereas the tissue sections of the testes of dogs in group B were similar to those of the control group. It was therefore concluded that infection of dogs with T. brucei adversely affected testicular morphology and function. Treatment with diminazene aceturate reversed the reproductive abnormalities caused by the parasite., (Copyright © 2013 Elsevier B.V. All rights reserved.)