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Suppression of Estrus in Cats

Gimenez F, Stornelli MC, Tittarelli CM et al: Suppression of estrus in cats with melatonin implants, Theriogenology 72:493, 2009.

Cat overpopulation is a large problem in much of the world. Surgical contraception has been the method of choice, but is not feasible in some countries because of economic limitations, and lack of organized programs. Control of reproduction is needed, but little work has been done in non-surgical feline contraception. Cats are long-day breeders; melatonin may signal the feline ovary, and exogenous melatonin may mimic shortening daylight. This study examined the usefulness and safety of heat, or estrus, suppression in cats with melatonin implants. Melatonin implants were given to nine queens, while five received a placebo, during the interestrus period. This was followed by a second implant during estrus. Vaginal cytology, behavior, and reproductive status were examined. The interestrus period was extended by two to four months in the queens receiving melatonin. Once suppression waned, and estrus occurred, pregnancy rates were not affected. The authors concluded that subcutaneous melatonin implants effectively, reversibly, and safely suppressed estrus in queens for 2 to 4 months. Additional studies are needed to suppress estrus in queens for the entire breeding season. [MK]
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Munson L, Bauman J, Asa C et al: Efficacy of the GnRH analogue deslorelin for suppression of oestrous cycles in cats, J Reprod Fertil Suppl 57:269, 2001.
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Levy J, Miller L, Crawford P et al: GnRH immunocontraception of male cats, Theriogenology 62:1116, 2004.
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