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Contents Measurement of circulating luteinizing hormone ( LH) concentrations in cats and temporal changes following ovariohysterectomy ( OHE) or possibly Gn RH vaccination may be informative for assessing their fertility, contraception or sterilization status. In this study, serum LH concentrations were measured in domestic cats ( n = 6) immediately prior to and up to 120 days post- OHE. Basal LH concentrations of females previously subjected to OHE ( n = 4; ~1.5 years post- OHE) were compared pre- and post-vaccination with a Gn RH immunocontraceptive, and to LH concentrations in intact females. Basal serum LH concentrations (2.67 ± 0.43 ng/ml; mean ± SEM) in intact females increased ( p < .01) by 30 days post- OHE (5.65 ± 0.87 ng/ml) but then declined ( p < .05) to pre- OHE levels (mean range, 3.26-3.62 ng/ml) at days 60-120 post- OHE. Serum LH (3.84 ± 0.51 ng/ml) in four females ~1.5 years after OHE tended to be higher ( p = .10) than those of intact females prior to OHE. Three months following first or second Gn RH immunocontraceptive vaccine treatment, serum LH values in females previously subjected to OHE decreased ( p < .05) to concentrations similar to those observed in intact females. Our preliminary results suggest that OHE of domestic cats causes a marked increase in basal LH levels within the first few weeks after ovariohysterectomy followed by a return to pre- OHE basal values over the next several months. Reduced LH concentrations after Gn RH vaccine may indicate the effectiveness of the immunocontraceptive in reducing the circulating levels of Gn RH, thereby reducing secretion of LH. [ABSTRACT FROM AUTHOR]

Contents Semen banking of domestic cats and wild felids represents a vital resource for their long-term conservation, but current methods require access to advanced training and specialized equipment. A newer method of semen collection, urethral catheterization of medetomidine-treated cats, allows recovery of high sperm numbers, but it is unclear if this approach permits maximal sperm recovery or is feasible using less expensive alpha-2 agonists. Similarly, a newer sperm preservation approach, vitrification, offers advantages of simplicity and minimal equipment needs, but its efficacy in combination with urethral catheterization has not been investigated. Our specific objectives were to (i) evaluate sequential semen recovery with urethral catheterization and electroejaculation in domestic cats, (ii) assess the effectiveness of a weak (xylazine) versus strong (dexmedetomidine) alpha-2 agonist for inducing sperm release, and (iii) compare post-thaw sperm motility, acrosome status and fertilizing capacity of catheter-recovered samples after vitrification or straw freezing. Results indicated that electroejaculation following repeated catheterization allowed recovery of additional spermatozoa (range, 11-32 × 106 sperm/male) and that xylazine was ineffective for inducing meaningful sperm release (range, 0-0.4 × 106 sperm/male). Post-thaw motility and acrosome status of vitrified catheter samples did not differ ( p > .05) from that of straw frozen samples. Preliminary results indicated that in vitro fertilization success (9/30, 30%) of vitrified catheter sperm did not differ ( p > .05) from that observed with straw frozen samples (17/30, 57%). In conclusion, urethral catheterization of dexmedetomidine-treated cats allows recovery of substantial sperm numbers but electroejaculation still may be warranted for maximal sperm recovery. Xylazine is not suitable as an inexpensive alternative to dexmedetomidine for catheterization. Vitrification of catheter samples results in comparable post-thaw parameters to straw freezing and may be adequate for use with oviductal insemination procedures. [ABSTRACT FROM AUTHOR]

Contents Artificial insemination ( AI) is potentially invaluable as an adjunct to natural breeding for the conservation management of non-domestic felid populations. The efficacy of AI, however, must be substantially improved for applied use, especially when using frozen semen. Our recent advances in using laparoscopic oviductal AI ( LO- AI) with low sperm numbers and freezing of cat semen in a soy lecithin-based cryoprotectant medium suggest that combining these two approaches might improve pregnancy outcomes with frozen-thawed spermatozoa. In this study, our objectives were to (i) assess the effect of two gonadotropin dosages (100 vs 150 IU eCG) on ovarian response in domestic cats and (ii) compare the relative fertility of frozen-thawed and fresh semen in vivo following LO- AI. All 16 females ovulated after gonadotropin treatment and were inseminated with fresh semen from one male and frozen-thawed semen from a second male. There were no differences between gonadotropin dosages in CL number, pregnancy percentage or litter size. Half (8/16) of the females conceived, with seven females giving birth to a total of 36 offspring. Paternity analysis showed that more kittens resulted from LO-AI with fresh (28/36, 78%) than frozen-thawed (8/36, 22%) semen, possibly due to impaired motility and longevity of thawed sperm. These results demonstrated that viable offspring can be produced by AI using semen frozen in a soy lecithin-based medium. Insemination with greater numbers of frozen-thawed spermatozoa, combined with further refinement of cat sperm cryopreservation methods, may be necessary to optimize pregnancy success with LO- AI in domestic and nondomestic cats. [ABSTRACT FROM AUTHOR]