Third trimester (Day 43 - 65)

It’s almost time! Down to the last three weeks before the litter arrives. My girl is looking pregnant, possibly a little or possibly very much so in some cases. During this trimester there will be many changes, most of which are quite normal.

What Is Happening

The third trimester begins on day 43 and continues until the litter is whelped, typically around day 63 post-ovulation, plus or minus a couple of days. This is the time in a dog's pregnancy when the most observable changes take place; her abdomen expands, her mammary glands develop, and she puts on weight. Unlike some species, puppies are undergoing development and substantial cell division right up until birth.

This trimester is when the pups grow rapidly.
❑ Develop hair and nails around day 45.
❑ Pups bones will begin by Day 50
❑ About ten days out from birth, Day 53, puppy brain development begins in earnest.
❑ I can usually feel the puppies moving by the eighth week. This is one of the most exciting feelings while we await the arrival of the puppies.

The bitches hormones that were steady during the second trimester change a lot during the third trimester. Because pregnancy in the dog is so short, whelping must occur while the placentas are still healthy enough to support the puppies. Towards the end of a normal pregnancy, around Day 65 post ovulation, placentas deteriorate rapidly resulting in stillborn pups. This is why I do multiple progesterone tests just prior to breeding to help pinpoint when ovulation occurred.

Changes in progesterone, relaxin, and prolactin prepare the bitch’s body for whelping, mothering, and milk production but the more critical chemical to trigger whelping is fetal cortisol, which is secreted as soon as the puppies’ mature. This is why bitches carrying only one or two pups may not go into labor. There just may not be enough cortisol from the pups. If I have a small litter of 1-2 pups, a c-section will be scheduled. The third trimester ends with the onset of Stage 1 labor or a c-section.

Weight Gain

She will gain most of her pregnancy weight during this trimester due to the puppies’ growth and weight of placentas. Pups and placentas each contribute approximately equal weight to her weight gains during pregnancy, so you may be able to determine how many pups she has by calculating how much weight she has gained. Then divide that gain by 2 and again by the average birthweight of pups (16 oz). I don’t do this as an X-ray will be taken 5 days prior to estimated delivery date. This will give me a more accurate count as we can see their skeletons.

Feeding and Supplements

She will continue the supplements and food that I have been using during the second trimester but will be increasing the amount of food based on the size of her litter. I usually split her food into three, four, even five or six meals a day, if she is struggling to get it all down.

❑ Small litter – feed her 10% more per pup of her maintenance amount (1-4 pups)
❑ Average litter – increase her food to 200% of maintenance or twice as much as I normally feed (6-9 pups)
❑ Large litter – increase her food to 250% of maintenance or 2 ½ times as much as I normally feed (9+ pups)

Exercise

During the third trimester, it's time to back off on exercise. Everything I’ve done up until now has prepared her for the arrival of her pups. Self exercise…bitches naturally do one critical strength exercise during this trimester—digging. This is beneficial to her as whelping approaches so there is no need to stop her, except to protect my yard and garden.

Whelping Box

Now is the time I setup the whelping box. This gives her time to get use to it in the room and she is free to investigate. It is interesting that when the times comes, my girls usually make their way to the whelping box. The box provides them with a safe and warm space for her and the puppies.

Between day 56-58 I will have an X-ray done. Once the X-ray is done I will post a picture of it for all to guess how many puppies are in her belly. Then, we wait and pray for a safe and healthy delivery of all puppies and mom.

Sincerely,
Tygold Golden Retrievers
Kelly Tynan