She has also been fielding complaints about cats causing disturbances by roaming, fighting and mating, particularly towards the east side of Masterton.
"It boils down to irresponsible pet ownership -- and those of us who love animals more than anything are left picking up the pieces," Mrs Qualtrough said.
"For so many reasons, de-sexing is a life-saving operation. If you want to give your pet the life it deserves, you will de-sex it."
Mrs Qualtrough said she and husband Hamish have had to deal with some heartbreaking situations -- including a litter of kittens who didn't survive a premature labour, and a six-month-old cat who accidentally smothered her babies.
"She was barely more than a baby herself -- it's the equivalent of an 11-year-old child giving birth.
"We don't want to shield the public from this side of our work: rescuing animals is not all rainbows and butterflies."
She said de-sexing a cat not only prevents pregnancy, but reduces the risk of infections that can be spread through indiscriminate breeding, such as feline immunodeficiency virus and calicivirus.
A complicated pregnancy can also cause chronic infections, and mastitis can be extremely painful in nursing cats.
"It's unnecessary suffering," Mrs Qualtrough said.
De-sexing a pet can have many other health benefits, said Nicola Haglund, a veterinarian at Vet Services Wairarapa.
De-sexing reduces the risk of ovarian and mammary cancer -- for example, a unneutered bitch who has had two heats has a one in four chance of developing mammary cancer -- and can, according to some studies, double a pet's life expectancy.
Dr Haglund said she supported breeding cats or dogs to carry on a particular pedigree blood line, or to improve the animal's gene pool.
"You want to make sure you're breeding an animal that's better than average, so all the good characteristics get passed on."
She warned pet owners who planned to breed to be vigilant when caring for a pregnant dog or cat, as a large litter can put strain on their body.
At The Q's Zoo, Mrs Qualtrough said she hears all kinds of reasons why people don't de-sex their pets -- with financial pressure being the most common.
"I know people say the cost of de-sexing is beyond them, and we understand that.But to have a cat or a dog is expensive full-stop -- so people need to be prepared to save up."
