According to the Guardian Rottweilers website, female Rottweiler dogs can reach sexual maturity as early as 6 months of age, though they should ideally not become pregnant this young. Most Rottweilers will not reach full growth until they are closer to 2 years of age. However, an unspayed animal may go into heat and is at risk of pregnancy if she encounters an unneutered male. Not all matings end in pregnancy, even when the breeding is planned. Knowing the signs of pregnancy in Rottweilers can help breeders and pet owners determine whether their animals will give birth.
According to Guardian Rottweilers, the first sign of pregancy in Rottweilers is vaginal swelling. This swelling begins in proestrus, or the beginning of the heat cycle. If the dog has mated and the mating was successful, this swelling does not decrease. In females that have not been impregnated, the vagina will return to a normal adult size and shape.
About a month after a successful mating, a pregnant female Rottweiler's nipples should become more prominent. They may grow slightly and protrude further from the dog's belly. The hair around the nipples may also recede to facilitate later nursing.
According to Guardian Rottweilers, dogs may have symptoms similar to morning sickness in humans. These usually appear around the third week of pregnancy and may include decreased appetite and an aversion to certain foods. In rare cases, the pregnant female may vomit. Pregnant females should be offered increased amounts of food, even if they show little interest in it. Guardian Rottweilers suggests increasing the food offered to double the normal amount by 4 weeks into the pregnancy. Females may also cease to eat and drink around 24 hours before labour starts.
According to the Vet Info website, female Rottweilers may exhibit vaginal discharge for the first week after breeding, as well as late in pregnancy. Normal discharges are normally colourless or faintly coloured and have little to no odour. A strong odour may indicate vaginal infection. Dogs with vaginitis may produce a reddish or coloured discharge. This condition is common in pregnant dogs and requires treatment only if the dog appears to be uncomfortable.