Change nothing for the first 4 weeks, add 10 percent from week 5, and add 25 percent over maintenance in the last 2 weeks. Those 3 steps land at about 1.3, 1.43 and 1.63 times resting energy by the final week, the range most veterinary nutrition texts describe. The work is not in the percentages. It is in 6 things you measure weekly so the steps happen on evidence rather than on how round the cat looks.
Weeks 1 to 4: Deliberately Flat
In the first 4 weeks the fetuses total under 10 percent of the weight the queen will gain, and mammary tissue has barely started. A 3.5 kg queen at maintenance eats about 58 g of a 4.0 kcal per gram dry food, and she should still be eating 58 g on day 28. Increasing early has 2 costs. The queen lays down fat she will carry into labor, and fat is the tissue that makes a difficult birth more likely, a conversation worth having with a vet rather than solving with a bigger bowl. The 4 flat weeks also give a baseline: 300 g gained by week 4 on unchanged food is a signal, not a reason to cut her food.
The Math: RER, Then a Multiplier
Resting energy requirement is 70 times body weight in kilograms to the power 0.75. For a 3.5 kg queen that is 70 times 2.56, or 179 kcal. Maintenance sits at 1.2 to 1.4 times RER, so 215 to 251 kcal, and 1.3 is a fair working number at 233 kcal. Every step in the plan is a percentage of that 233, not of what she happens to be eating. A queen already 15 percent over maintenance before pregnancy is a different calculation and a case for a vet.
| Stage | Days | Multiplier on RER | kcal per day, 3.5 kg | Grams of 4.0 kcal/g food |
|---|---|---|---|---|
| Weeks 1 to 4 | 0 to 28 | 1.30 | 233 | 58 |
| Weeks 5 to 6 | 29 to 42 | 1.43 | 256 | 64 |
| Week 7 | 43 to 49 | 1.50 | 268 | 67 |
| Weeks 8 to 9 | 50 to 65 | 1.63 | 291 | 73 |
Those gram figures assume a 4.0 kcal per gram dry food, which is printed on the bag. A 3.8 kcal food needs 61 g at the same 233 kcal, and a 4.3 kcal food needs 54 g, a 7 g spread for the same energy. Divide kcal by the number on the label once, write the answer on the lid, and stop doing arithmetic at 6 am.
The 10 Percent Step at Week 5
Week 5 is when fetal growth starts to cost the queen something measurable, roughly day 29 to 35. Add 10 percent, which is 6 g of dry food for a 3.5 kg queen, and hold it for 2 weeks. Do not add it as a second bowl. Split the day into 3 or 4 meals at this point, because a uterus pressing on the stomach means she cannot take 58 g in 1 sitting by week 6, and a queen who walks away from a full bowl looks like a cat who has gone off food when she is simply out of room.
Track grams eaten, not grams offered. A 10 percent increase that she leaves in the bowl is not an increase, and 3 days of a half-empty bowl in week 6 is the first place a problem shows up, well before weight drops.
The 25 Percent Step in the Last 2 Weeks
From day 50, energy need climbs fastest: 291 kcal for the same 3.5 kg queen, 73 g of the 4.0 kcal food, and a 1.63 multiplier that matches the late-gestation range. Appetite often cannot keep up with the arithmetic in the final 9 to 10 days, because the stomach has less space than it did at week 4 while demand is at its highest. Two workable answers. Raise energy density instead of volume, moving to a food at 4.3 to 4.5 kcal per gram or adding a palatable wet food at 1.0 to 1.1 kcal per gram. Or feed 5 to 6 small meals, including 1 at night, since a queen in the last week often eats most between 10 pm and 6 am.
This is also the window to stop changing anything else. No new protein source, no new brand, no treats she has not had, inside the last 14 days. A queen with diarrhea on day 60 is a much harder case than the same diarrhea on day 30.
Six Things to Monitor
Six numbers, once a week, on the same sheet. Weight on a 1 g or 10 g scale, same day of the week. Body condition score on the 1 to 9 scale, with ribs felt but not seen as the target. Grams eaten against grams offered, so a 20 percent drop is visible in 1 day. Water intake, roughly 40 to 60 ml per kg per day, higher on dry food. Stool score on the 1 to 7 scale, with 3 as the target and 1 or 7 as a call. Vomit count, since 1 hairball in 7 days is normal and 3 vomits in 3 days is not.
Weight gain is the one that carries the others. A queen should gain 25 to 40 percent of her pre-pregnancy weight across the whole 63 to 65 days, so at day 42 she is usually 17 to 25 percent up. A flat week in mid-pregnancy is worth a vet call; a flat week in the last 10 days is an emergency. The week-by-week energy and weight targets are set out in queen pregnancy nutrition.
Water, Stool, and the 3-Day Rule
Dry food and a compressed stomach is the standard recipe for constipation in the last 2 weeks. 40 to 60 ml per kg per day is the target, and a 3.5 kg queen drinking under 140 ml on dry food is behind. A wet food at 78 percent moisture delivers about 60 ml per 80 g pouch, which is why 1 pouch a day fixes most of this. The 3-day rule: no stool for 3 days, or 2 days of straining with nothing passed, goes to the vet the same week, not after the kittens arrive.
After Birth, the Number Changes Again
Lactation is not gestation plus a little. Energy need goes to 2 to 3 times maintenance by week 3 of nursing, which is 470 to 700 kcal for a 3.5 kg queen with 4 kittens, and that is a different plan with its own arithmetic, set out in queen postpartum feeding math. The transition that matters at birth is simple: keep the week-9 food, keep the 5 to 6 meals, and start adding volume within 24 hours of the last kitten, because milk output peaks in week 2 to 3 and the queen cannot catch up later.
Five Steps for This Week
- Weigh the queen and write her maintenance grams on the food lid today, kcal divided by the label number.
- Set the 3 step dates on a calendar: day 29 for +10 percent, day 43 for +15 percent, day 50 for +25 percent.
- Print 1 sheet with the 6 monitoring rows and fill it every 7 days, same day, same hour.
- Split the day into 3 meals now and 5 to 6 by day 50, with 1 meal after 10 pm.
- Freeze a 10-day food supply of the exact product she is on before day 50, so nothing changes in the final 2 weeks.
What the 10-day stock and a late-pregnancy food swap cost is in the cost tools.
Frequently asked
Why not just feed a pregnant queen all she wants?
Free feeding in the first 4 weeks adds fat rather than fetal mass, because the litter is under 10 percent of total pregnancy gain at that stage. Excess body fat is one of the factors that make a difficult birth more likely, and a queen who starts labor overweight also has less room to gain the 25 to 40 percent the pregnancy itself needs. Feed to 1.3 times RER until day 28, then follow the 3 steps.
How do I know the extra 10 percent is actually being eaten?
Weigh what goes in and what comes back, in grams, once a day. A 10 percent step for a 3.5 kg queen is only 6 g of dry food, which is easy to lose in a bowl. If 20 percent of the offered food is left for 3 days in week 5 or 6, treat that as a signal, not as fussiness, and check stool, temperature and the food's freshness before adding more.
Can I switch to kitten food in the last two weeks?
Many vets do recommend a growth or all-life-stages food, but the switch takes 10 days, 25 percent of the new food per day, so it has to start by day 45 to be finished before day 55. Do not start a new food inside the final 14 days. If she is already on a food at 4.3 kcal per gram or more, raising volume and splitting meals is the safer route.