Contents: The aim of this study was to assess whether refractoriness to long photoperiod (LP) could be reversed by subjecting tomcats to a period of short days. Our hypothesis was that photoperiod changes can avoid refractoriness and restore sperm quality and production to that before refractoriness. Tomcats (n = 6) were housed in a conditioned room withLP(12L: 12D) for 45 days of acclimation and then maintained underLPfor 18 month. Then, tomcats were changed to a period of decreasing light at a rate of 8 min/day for 1 month. Tomcats stayed for 1 month with short photoperiod (SP; 8L: 16D) and then were switched back to a period of increasing light at a rate of 8 min/day for 1 month. The experiment was completed after tomcats remained inLPfor 2 months. Toms were anaesthetized and semen samples were collected by electroejaculation every 2 weeks. Sperm parameters were evaluated in all ejaculates, and data were analysed byanova. Motility, velocity, volume, sperm concentration, total sperm count, viability, acrosome integrity, plasma membrane integrity and sperm morphology were higher duringLPcompared with a refractoryLP(p < 0.01). Likewise, velocity, viability, acrosome integrity, plasma membrane integrity and sperm morphology were higher in aLPcompared with aSP(p < 0.05). On the other hand, motility, volume, concentration and total sperm count were similar betweenLPandSP(p > 0.20).Whereas motility, velocity, viability, acrosome integrity and plasma membrane integrity were similar in a refractoryLPcompared withSP(p > 0.05), volume, sperm concentration, total sperm count and sperm morphology were lower in a refractoryLPcompared withSP(p < 0.05). In conclusion, refractoriness and reduced sperm production and quality induced by a prolongedLPof 18 month can be restored after placing tomcats to aSP.

Contents: The aim of this study was to assess epididymal sperm characteristics and serum testosterone concentration in cats under natural photoperiod. The hypothesis was that natural photoperiod induces seasonal changes in spermatozoal quality and serum testosterone concentration. Mixed breed tomcats (n = 43) that underwent bilateral orchiectomy at a municipal public pet shelter were used in the study. Epididymides were divided into two groups according to time of castration. In Group I, toms were castrated during increasing light (IL; [winter and spring; n = 24]), and group II, during decreasing light (DL; [summer and fall; n = 19]). Only mature toms castrated in the two lasts weeks of each season were included in this study. Sperm samples were obtained by cutting the cauda epididymis in Tris solution and tested for motility (MOT,% motile), velocity (VEL, 0–5), total sperm cells (TS, 10⁶), acrosome integrity (ACR,% intact; FITC‐PSA), plasma membrane integrity (MI,%intact; CFDA‐PI) and sperm morphology (SM,% normal). Before orchiectomy, blood samples were taken to measure serum concentrations of testosterone (T2) by a solid‐phase RIA. Data were analysed with the mixed procedure of SAS. Toms castrated during IL had higher sperm plasma membrane integrity and better sperm morphology compared to toms castrated during DL (69.0 ± 2.7 vs 60.6 ± 2.1, p < 0.01; 45.9 ± 2.5 vs 35.9 ± 3.4; p < 0.02; respectively) and tended to have higher sperm motility and total number of sperm cells compared to toms castrated during DL (56.3 ± 2.8 vs 47.3 ± 3.7, p < 0.06; 13.8 ± 1.4 vs 10.0 ± 1.8, p < 0.09). However, velocity, acrosome integrity and serum testosterone concentrations were similar between both groups (3.5 ± 0.1 vs 3.4 ± 0.1, p > 0.6; 45.8 ± 3.3 vs 44.0 ± 4.0, p > 0.72; 0.76 ± 0.15 vs 0.59 ± 0.19, p > 0.51; respectively). In conclusion, natural photoperiod induces seasonal changes in sperm quality with a moderate variation in serum testosterone concentrations.

Treatment with cloprostenol, a prostaglandin synthetic analogue, was evaluated in five queens with open-cervix pyometra. Cloprostenol was administered (5 μg/kg body weight SC) on 3 consecutive days and amoxicillin (20 mg/kg body weight IM) on 7 consecutive days. Transient post-injection reactions caused by cloprostenol administration included diarrhea, vomiting and vocalizations. Reactions began as quickly as 10 mins after cloprostenol administration and lasted as long as 30 mins. All queens improved clinically after cloprostenol treatment and remained healthy until the end of the study, 1 year after treatment. All queens resumed normal estrous cycles without further treatment and two (40%) delivered a normal litter. In conclusion, use of cloprostenol is an acceptable treatment for open-cervix pyometra in queens.