Abstract The cryopreservation reduces ram sperm quality, decreasing the pregnancy rate of ewes inseminated with thawed sperm. Hence, we aimed to improve the post-thaw quality of ram sperm replacing egg yolk on Tris-Glucose extender with different concentrations of LDL (2 or 8%), associated with the addition of 10 mM non-enzymatic antioxidants (ascorbic acid, hydroxytoluene butylate, ascorbyl palmitate, and trehalose). Semen samples were collected from six rams, split into different treatments, and frozen. After thawing, kinematic (CASA), structural (propidium iodide and carboxyfluorescein diacetate) and functional (hypoosmotic test) sperm membrane integrity was assessed. Total motility, VCL, and LIN were also assessed in thawed samples during 3 h of incubation (38 °C). The results showed that hydroxytoluene butylate at 10 mM in Tris-Glucose extender with 8% LDL improved velocity parameters immediately post-thaw compared with Tris-Glucose egg yolk extender, as well as prevented the reduction of total motility and VCL after incubation. There was no benefit of adding ascorbic acid and trehalose. Moreover, for the first time, it was shown the motility impairment promoted by ascorbyl palmitate to ram sperm.

Abstract The aim of this research was to evaluate the use of pyridoxine hydrochloride and its associated side effects in the treatment of pseudopregnancy in female dogs. A total of 40 female dogs, with no defined breed, in non-gestational diestrus, with clinical complaint of milk production were selected. The female dogs were divided into four experimental groups of 10 animals each, treated orally for 20 days with 10mg/kg/day (G1) and 50mg/kg/day (G2) of pyridoxine hydrochloride (vitamin B6), 5μg/kg/day of cabergoline (G3), and with a placebo, in the case of the control group (G4). The effects of the treatments on milk production were investigated, as well as possible systemic side effects, macroscopic uterine and ovarian alterations, and uterine histology. During the investigated period, G2 and G3 were equally efficient (P>0.05) in lactation suppression, differing (P>0.05) from the other groups. There were no systemic side effects or uterine changes associated with administration of the studied drug. Vitamin B6 (50mg/kg) has shown to be a safe and economically viable alternative for lactation interruption in female dogs with pseudopregnancy.

Resumo A ovulação em gatas é induzida por um reflexo neuroendócrino atribuído à estimulação mecânica dos receptores sensoriais durante o coito. Esta estimulação pode ser simulada com auxílio do swab vaginal, desencadeando a pseudogestação. Objetivou-se verificar a eficiência da indução de ovulação com swab, a fim de estabelecer um tratamento contraceptivo natural para felinos domésticos, bem como os efeitos sobre o útero do uso repetido dessa técnica. Na primeira fase do trabalho, foram avaliados 12 animais em três ciclos estrais consecutivos. No primeiro ciclo (T1), houve estimulação vaginal com swab. No segundo ciclo (T2), foi utilizado macho vasectomizado para cópula. No último ciclo (T3), a ovulação foi acompanhada sem estímulo (controle). Na segunda etapa do trabalho, 13 gatas foram submetidas a sucessivos estados de pseudogestação com intuito de verificar os efeitos da estimulação mecânica sobre o útero. A confirmação da ovulação em todas as etapas do trabalho foi realizada por meio da mensuração dos níveis de progesterona. A estimulação vaginal com swab apresentou resposta similar à obtida por monta natural (P>0,05). Algumas gatas apresentaram modificações uterinas discretas; no entanto, nenhum desses achados foi considerado de relevância patológica. Desta forma, a indução de ovulação com swab mostrou-se segura e sem efeitos colaterais expressivos.

Abstract A neuroendocrine reflex attributed to the mechanical stimulation of sensory receptors during copulation induces ovulation in cats. This stimulation can be simulated with a vaginal swab, triggering pseudopregnancy. The efficiency of ovulation induction with swab was evaluated in order to establish a natural contraceptive treatment for domestic cats as well as to analyze the effect on uterus of the repeated use of this technique. At the first phase of the study, 12 animals were evaluated in three consecutive estrous cycles. In the first cycle (T1), vaginal swab stimulation was applied. In the second cycle (T2), a vasectomized male was used. In the third cycle (T3), ovulation was accompanied unstimulated (control). At the second phase of the study, 13 female cats were induced to successive pseudopregnancy states to check the effects on the uterus. Confirmation of ovulation in the two phases of the study was carried out by measuring progesterone serum levels. The vaginal swab stimulation showed a similar response to that obtained by natural mating (P>0.05). Some cats showed mild uterine changes without pathological relevance. Thus, ovulation induction with swab is secure and without significant side effects.