Monday, June 10, 2013

To Spay or not to the question

The argument rages on. To spay or not to spay. To neuter or not to neuter. Of course, some opinions are based on religion and personal philosophies. My questions revolve around just two parameters, in clear order of priority:
  1. What is best for the health of my dogs
  2. What is best for the canine community at large
When I saw a course on Canine Theriogeniology  by Dr. Margaret V. Root of University of Minnesota, offered on Coursera, I took it up without thinking twice and I am happy I did. My mind is most at peace when I have access to information and that is exactly what was made available to me as part of this course and I am happy to present the facts as was taught to me.

In this blog, I'll focus on the female dog. I'll focus on male dogs in my next blog. First, I'll talk about how evaluate risks, then I can present the risks. After all this, I’ll add details to some of the terms and disorders I have talked about, in case any of you want details. I'll write another blog with details of neutering.

Parameters to judge risk

One of the most interesting things I learned as part of this course was how to evaluate risk. Once described, it seems fairly obvious. But it never occurred to me to look at risks this way. When we talk or risks, we need to look at 2 parameters:
  1. Severity. How serious is this risk really. Is it a mild inconvenience to the dog, is it easy to treat or is it something very serious that has is lethal or very difficult to treat
  2. Likelihood: How likely is it that the dog is going to suffer from a particular ailment. If the occurrence is really low, then despite high morbidity, it might be less of a consideration

To make this discussion a little more easy to follow, I’ll represent this pictorially in 4 boxes.

The Risks

The Risks of NOT Spaying

Below you'll see here, the red box is very busy. Loads of risks there. And because it’s in the red box it means we are looking at severe risks that are highly likely to occur. So I’ll spend a little time on what these
risks are.

Below are some details of the risks. Click on each of the images to enlarge it and read more. Check the end of the blog in the deep-dive section for further details, if that's of any interest.

The Risks of Spaying

Yup, there are risks here as well. Once we spay the bitch there are a few conditions that are more likely to occur. Let me put these on a similar diagram.

In this diagram you will notice that the red segment is relatively empty. That’s a relief because we are either looking at mild conditions or really rare conditions. There are several cancers listed in the rare conditions. So we did not do a deep dive into these cancers. But what is known is that the occurance of these cancers is very very low in dogs in general. Though there are some studies that suggest the occurrence of these cancers increase after spaying, it is not to a great degree and the studies are not yet conclusive enough.

Obesity and UI seem to be likely, but we were taught that they are easy to manage and should not really be worrying us as much. Also, it seems like the occurrence of UI can be reduced if the bitch is spayed after 3 months.

To Spay or Not to Spay…is my question

Now, overall, this seems quite uplifting. When we are looking at spay or not to spay, since the red box is NOT busy in one scenario, it seems like the less dangerous path for us to take. I hope these 2 diagrams will help you decide which scenario you are more comfortable with.

One final note on the best time to spay: Spaying before 3 months seems to put the dog at higher risk of UI. But spaying AFTER the first heat seems to put the dog at higher risk of Mammary Cancer. So the sweet spot seems to be around 6 months, just before the first heat. I believe when the female has her first heat could be breed dependent. So, best to talk to your vet about it.

A little bit of deep dive for the super interested

Canine Reproductive System

I wanted to put forth some of the unique characteristics of the canine reproductive system that are relevant to the discussion on spaying.

Impact of Anatomy on Pregnancy in Bitches

I pointed out that pregnancy itself was risky in dogs. Here I want to detail out a little bit on why I said that.

One striking detail that was drummed into our heads during the class was the structure of the bitches vagina – very very long and narrow and tilting upward, with a muscle inside it that further narrows the passage. Thanks to this small passage, inserting anything into the vagina is an uncomfortable proposition for the dog.

Pregnancy by itself is complicated in dogs because pups grow their initial phase, not in the uterus, but in uterine horns. And unlike in humans, pups don’t have a standard size that they grow it. The size they grow to is in proportion to the litter size. The smaller the litter size, the larger the pups, complicating whelping. So, pregnancy, from what we were taught is far more complicated in dogs than we are led to believe, not just for the pups but for the mother as well. Helping the mother during whelping is difficult due to this very long vagina. Most other diagnostic tests also face complicates due to this extra long vagina.

Estrous cycle and it's impact on bitches' health

The second interesting note for me was the estrous cycle of a bitch. In humans and most other species, the female first produces the hormone Estrogen and when the body realizes that there is no pregnancy, the body does not produce the next hormone – Progesterone. In dogs however, the body does not recognize that the bitch is not pregnant and thus goes ahead producing Progesterone and the body of the dog behaves as if she has conceived. This is a relevant detail because the repeated exposure of the uterus to Estrogen and Progesterone exposes the uterus to the very deadly condition - Pyometra. As mentioned above, Pyometra is a condition where the uterus is weakened to a point where it becomes susceptible to other naturally occurring bacteria in the dogs body. The uterine walls get so weak  that if someone palpates the stomach of the dog to figure out why the stomach is bloated, the uterus could burst causing rapid death!

Other Disorders

Urinary Incontinence(UI)

This is a condition where the dog loses control over her urinary bladder. This apparently occurs frequently in spayed dogs, particularly ones that are spayed before the age of 3 months. However the good news is that this is not really detrimental to the dog in any other way, does not inconvenience the dog, just the owner who now needs to get a rubber sheet. Also, it’s supposed to be a condition controlled easily with medicines. Since the doctors conducting the course were not willing to do diagnosis during the course and prescribe medicine, I don’t have medicine names for any of these. But I would imagine our vets can tell us about it.

Mammary Neoplasia

A short not on Mammary Neoplasia or Breast Cancer. This was explained as one of the most commonly occurring cancer in female dogs. I also wanted to add that we were taught that 50% of the times it’s malignant, meaning it spreads. That’s the worst kind. This is definitely something to watch out for

No comments:

Post a Comment