The Use of Natural Phenomenon in Obtaining Pregnant Rats and Mice as Experimental Animals with The Same Gestational Ages

Teguh Wahju Sardjono, Harry Kurniawan Gondo, Rivo Yudhinata Brian Nugraha, Anisa Tiara Putri, Meyland Citra Oktri Sienty Effendy


Hormonal oestrus synchronization is often used to obtain the same gestational ages animal models, but it may not physiologic nor practical. This research was conducted to find out a simple method in obtaining physiologic pregnant experimental animals. We used 120 female rats and mice each, divided into 16 groups with 15 members each. They were classified according to the state of parities, pair or group mating, and synchronization of oestrous. The estrous synchronization is done by utilizing the natural phenomenon (Lee-Boot, Pheromone, and Whitten effect). All nulliparous and multiparous models then were simultaneously mated for one night in pairs (1:1) or in groups (1:5) subsequently. Pregnancy rates were noted based on the number of models delivering pups on day 19-23 post-mating. The highest pregnancy rate was noted in group of multiparous, synchronized and monogamous rats (86.7%), followed by nulliparous, synchronized and monogamous rats (73.3%) and multiparous, synchronized and monogamous mice (60%) (p<0.05). Synchronization of the estrous and monogamous mating of rats or mice had significant roles in pregnancy rates (p<0.05). To get a high number of pregnant rats or mice models, we suggest to use the multiparous, estrous synchronized and monogamous simultaneous mating within one night.


rats, mice, pregnant animal models, oestrus synchronization, LeeBoot Effect

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Franco NH (2013) Animal Experiments in Biomedical Research: A Historical Perspective. Animals 3: 238-273.

McLeod C and Hartley S (2017) Resposibility and Laboratory Animal Research Govenrnance. Science, Technology & Human Values XX (X):1-19.

Giridaran NV & Kumar V (2000) Use of Animal in Scientific Research. Indian Council of Medical Research. Ministry of Health and Family Welfare, New Delhi Pp. 1-27.

Morgan CJ, Elangbam CS, Berens S, Janovitz E, Vitsky A, Zabka T et al. (2013) Use of Animal Models of Human Disease for Nonclinical Safety Assessment of Novel Pharmaceuticals. Toxicologic Pathology 41 (3) : 508-518. doi: 10.1177/0192623312457273.

Biosecurity Victoria (2011) Guidelines for the Ethical Use of Animals in Research and Teaching. Department of Primary Industries, 1 Spring Street, Melbourne 3000.

Glasow PA (2005) Fundamentals of Survey Research Methodology. Mitre Product. Washington. P.2.1 -2.3.

Sentilkumar K, Selvaraju M, Ezakial-Napolean R, Doraisami KA & Mohan R (2016) Pattern of Oestrus and Fertility Rate Following Synchronization of Ovulation in Tellicherry Goats. International Journal of Science, Environment and Technology 5(5): 3289-3296.

Badawi ME, Makawi SEA, Abdelghaafar RM & Ibrahim MT (2014) Effect of Oestrous Synchronization using PGF2α on Subsequent Fertility of Nubian Goats (Capra hircus). Journal of Agricultural and Veterinary Sciences 15(2): 45-52.

Omontese BO, Rekwot PI, Ate IU, Ayo JO, Kawu MU, Rwuaan, et al. (2016) An update on oestrus synchronisation of goats in Nigeria Asian Pacific Journal of Reproduction 5(2): 96–101.

Islam R (2011) Synchronization of Estrus in Cattle: A Review Veterinary World 4(3): 136-141.

Dhami AJ, Nakrani BB, Hadiya KK, Patel JA, Shah RG (2015) Comparative efficacy of different estrus synchronization protocols on estrus induction response, fertility and plasma progesterone and biochemical profile in crossbred anestrus cows, Veterinary World 8(11): 1310-1316.

Sen U & Onder H (2016) The effect of estrus synchronization programmes on parturition time and some reproductive characteristics of Saanen goats, Journal of Applied Animal Research 44 (1): 376-379

Andreollo NA, dos Santos EF, Araujo MR & Lopes LR (2012) Rat’s Age Versus Human’s Age: What is the Relationship?. ABCD Arq Bras Cir Dig 25(1): 49-51

Sengupta P (2013) The Laboratory Rat: Relating Its Age With Human’s. Int. J. Prev Med 4(6): 624-630.

Smith J.B. & Mangkoewidjojo S (1987) The Care Breeding and Management of Experimental Animals for Research in the Tropics. International Development Program of Australian Universities and Colleges Limited (IDP). 36-38.

Bogdanske JJ, Stella SHV, Riley MR & Schiffmann BM (2010) Laboratory Mouse, Procedural Techniques Manual and DVD. Wisconsin Alumni Research Foundation, Laboratory CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL. 33487-2742.

Bogdanske JJ, Stella SHV, Riley MR & Schiffmann BM (2010) Laboratory Rat Procedural Techniques Manual and DVD. Wisconsin Alumni Research Foundation, Laboratory CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL. 33487-2742.

Lambert R (2007) Breeding Strategies for Maintaining Colonies of Laboratory Mice. A Jackson Resource Manual. The Jackson Laboratory.

Animal Care and Use Program (2013) Best Practices for Optimizing Mouse Breeding Programs. University of California. Berkeley.

Sardjono TW (2005) Influence of Toxoplasma Infection on Pregnancy Outcome through Gamma Interferron (IFN-γ), Activation of Caspase-3 and Apoptosis of Placental Cells. PhD Thesis. Airlangga University. Surabaya.

Jimenez, A (2016) SOP #608 Mouse Breeding Colony Management. McGill Comparative Medicine & Animal Resources Centre.

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