Determining if a doe is pregnant can be a bit of a mystery, particularly if a potential breeding/pregnancy is unplanned. Goosemoose Pet Portal. Next time you buy a rat either get better at sexing, or go through a breeder who should know right away which sex the babies are. The babies are showing more color pigment and have clearly grown in size and weight. This can be a very anxious time for either a new rat owner or a breeder. – The First Two Weeks ... and they will be two weeks old as of tomorrow! Is my 5 week old rat pregnant? Next time you buy a rat either get better at sexing, or go through a breeder who should know right away which sex the babies are. pika seemed depressed cuz he was all alone so i went & bought him a MALE friend. pregnancies last approximately 10 weeks, you wont however notice until about 6-8 weeks when she would become very pear shaped. So You’ve Got a Pregnant Rat… Now What? Just be readdy for some unfair squabbling. At this point, it begins a rapid deceleration to the normal fetal heart rate for mid-pregnancy to about 120 to 180 bpm. ... Can a 8 month old rat terrier get a 2 year old apple head Chihuahua pregnant? Do not spay past one week after breeding. Shown below are the Witschi standard stages of development and the timing and specific features that identify each stage. Taconic received stock from the NIH Animal Genetic Resource in 1970. 2 Days. Then, every month do it again, and see how they compare! It can be seen by transvaginal sonogram (TVS) as early as 22 days after fertilization/ovulation or 5 weeks 1 day after the last menstrual period. The babies are already showing pigment. I picked up 2 female rats from a breeder on Monday and one of them is Definitely pregnant! therefore there is a chance your girl is pregnant, girls come in to season every 15-17 days for 24 hours, she may be lucky and not be pregnant. Now i notice shes getting a lil fat. These are all Russian Blue. Furthermore, 3-6-week-old females can be induced to ovulate with a specific regimen of hormone treatment as described in Section 6.2.2.1. Between six and eight weeks old, your new rat will also go through the ratty equivalent of puberty and adolescence. Determining if a doe is pregnant can be a bit of a mystery, particularly if a potential breeding/pregnancy is unplanned. Sprague . ... especially when it comes to the darker colors. The rats were refreshed with NIH Genetic Resource stock in 1998. My nine week old used to pick on the young one now they snuggle and everything. The fetal heart activity is one of the earliest signs that the pregnancy is viable. Taconic’s proven process ensures timed-pregnant rats bear litters within a 24-hour window of your desired gestational age. There is also a slowing of the normal fetal heart rate in the last 10 weeks of pregnancy, though the normal fetal heart rate is still about twice the normal adult's resting heart rate. The option of spaying the pregnant rat to abort the babies. However, many times it's not seen until exactly 6 weeks. See also the Rat Timeline which gives a day by day sequence and adds additional research findings on rat development. Therefore, using females that are at least 8 weeks old will increase the likelihood that they will become pregnant. The rats are maintained as an outbred closed colony. I just got my hairless rat on saturday the 29th of september. The condition usually appears in rats 4-6 weeks of age and causes bloating, but can occasionally be found in rats a few months old. The Sprague Dawley® outbred model was developed by Sprague Dawley, Inc. NIH received stock from Sprague Dawley, Inc in 1945. They are only 6 weeks! So anyways I'm really worried for her as she is so young! Thus, the current review attempts to compare rat and human age at different phases of their life. 6 Days. The Hsd:Sprague Dawley ® SD ® rat has a wide array of historical research use including in the field of cardiology.