The Secret to Controlling Feral Cat Colonies

More on PawNation: Cats, Causes, Feral Cats

Feral cats ... now there's a topic that is guaranteed to raise a few hackles. In an attempt to promote common ground between all the different points of view about how, or how not to manage feral cat colonies, I want to share the results of a study published in the August 15, 2013 issue of the Journal of the American Veterinary Medical Association (JAVMA).

The researchers used computer modeling to predict the effects of three different management techniques, Trap-Neuter-Release (TNR), Trap-Vasectomy/Hysterectomy-Release (TVHR), and lethal control (LC). Here's a summary of what they found:

"Management of feral cat colonies by TVHR has not been suggested previously and may be more effective at decreasing population size because cats retain reproductive hormones and normal social behavior is maintained. Vasectomy does not alter a male cat's sexual drive or social status, so cats maintain their position in the breeding hierarchy, may better prevent immigration of intruding males into the colony, compete for females as before surgery, and continue to copulate but in an unproductive fashion. Coitus initiates a prolonged, nonreceptive 45-day pseudopregnancy period in females, thereby reducing the chance of a fertile mating. After TVHR, female cats continue to attract males and compete with sexually intact females for male courting and breeding time.

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"Unless > 57% of cats were captured and neutered annually by TNR or removed by lethal control, there was minimal effect on population size. In contrast, with an annual capture rate of ≥ 35%, TVHR caused population size to decrease. An annual capture rate of 57% eliminated the modeled population in 4,000 days by use of TVHR, whereas > 82% was required for both TNR and lethal control. When the effect of fraction of adult cats neutered on kitten and young juvenile survival rate was included in the analysis, TNR performed progressively worse and could be counterproductive, such that population size increased, compared with no intervention at all. [The paper mentions that only 12-33% of kittens in hormonally intact feral cat colonies survive to 6 months of age, but that rate increases when TNR is instituted, probably because of an increased tolerance of neutered cats.]"

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So, if TNR and LC are often ineffective at best and counterproductive at worst, it sure seems like giving TVHR a try makes sense. The obvious next step would be to try a instituting a TVHR program and monitoring its success (ideally in comparison to a TNR control). Most veterinarians have probably never performed a vasectomy or hysterectomy on a cat, but I'd bet the procedures wouldn't be too difficult to learn.

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The JAVMA article also provides a lot of evidence that supports the need to do something about feral cat colonies. Leaving the animals to fend for themselves is inhumane. The authors refer to a PhD thesis that revealed that in a feral cat colony that was part of a TNR program, the median survival time for intact adult males was only 267 days (less than a year!) and for intact adult females it was just 593 days. Interestingly, the median survival time for neutered males and females was much longer (>730 days), which on the surface looks like a good thing, but this increased survivability is part of the reason why TNR programs often fail to reduce the size of the population over the long run.

Dr. Jennifer Coates

Reference

Estimation of effectiveness of three methods of feral cat population control by use of a simulation model. McCarthy RJ, Levine SH, Reed JM. J Am Vet Med Assoc. 2013 Aug 15;243(4):502-11.

"The Secret to Controlling Feral Cat Colonies" originally appeared on PetMD.com.

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BARB

i HAVE BEEN FEEDING A FERAL FOR 6 MONMTHS. SHE WASN JUST A KITTEN WHEN SHE CAME, SHES ASMALL CAT BUT TO DAY SHE BROUGHT 6 TINY BLA;CK KITENS OUT. tHNEY ARE BLACK WITH BLUE EY ES AND ABOUT 6 OR 7 WEEKS OLD.iS THERE A NO KILL CAT RESCUE i CAN CALL?
Barb H

October 19 2013 at 11:57 PM Report abuse rate up rate down Reply
oujoou

Desert feral cats are really interesting. I was in Kuwait once and there are feral cats all over the place. One Egyptian student said I was a generous soul because I would play with them. I never thought twice before letting one gnaw gently on my finger. Nowadays . .. people worry about disease and parasites when they see a feral ANYthing. I know kids who won't lie on their lawns for fear of Lyme's disease. :( Times have changed people. I think for the worse. :(

October 19 2013 at 4:03 AM Report abuse rate up rate down Reply
meresprit

BS-The TNR programs here have worked VERY well. The number of cats being euthanized in shelters is DOWN and continues to go DOWN. Where did you folks get this Misinformation? I have managed a feral colony for years and really don't appreciate someone spouting off UNTRUTHS.

October 18 2013 at 11:40 PM Report abuse +1 rate up rate down Reply
josephyannuzzi

I have been rescuing and caring for feral cats since 1988 and the TNR program has worked very well for me. The only problem is that once you have your colonies all spayed and neutered, people who know you are the caretaker of a colony will dump unwanted cats and you have to start over again. Stay with TNR, regardless of what is said in this article, it works.

October 18 2013 at 11:27 PM Report abuse +1 rate up rate down Reply

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