E - Maternal Behaviour
Learning Objectives:
By the end of this laboratory you should be able to:
Describe a number of maternal behaviours in the female rat.
Compare and contrast the maternal behaviour of virgin female rats to rat dams.
Introduction:
The maternal behaviour of the laboratory rat is a highly organized phenomenon that appears spontaneously in postpartum mother rats, but not in males or virgin females (Fleming and Rosenblatt, 1974; Jans and Woodside, 1990). Important hormonal events during pregnancy lead to neural changes that prime a mother for maternal behaviours. Maternal behavior is sensitive to various drugs, and as such, can be an important screen for therapeutic drugs that may alter human maternal behaviour. Post partum depression and infanticide can be tragic events for new families, and understanding the hormonal and neural changes that accompany maternal behaviour is an essential foundation for decreasing the suffering experienced by some new mothers.
Procedure:
Preparation: Read Chapter 27: Maternal Behavior (Rees et al., 2005) before the lab this week. A few weeks ago you studied sexual behaviour in rats. Hopefully this was a fruitful endeavor, providing you with pups to study for today’s lab. Collect a cage with a mother and pups, a cage with a virgin female, and 2 clean empty cages. Put on gloves before handling any pups.
Observing Undisturbed Maternal Behaviour: To start, simply watch the mother in her home cage interacting with her pups. First assess the quality of the nest (see Rees et al. (2005) p. 290). Note the following behaviours: body licking, anogenital licking, and nursing. Note the mother’s posture. Observe the mother and litter for 30 minutes.
Pup Retrieval: Remove the pups to a clean cage and place them in a huddle. Remove the mother to a separate clean cage. Wait 5 minutes. Place the mother back in her home cage for 5 minutes and note her behaviour. Then place the pups back into their home cage in the corner diagonally opposite the nest. Observe the mother’s retrieval behaviour and time how long it takes for her to move all of the pups back to the nest. Note how she interacts with the pups beyond that of carrying them back to the nest.
Virgin Female Response to Pups: Remove both the pups and the mother back to their clean cages. Place the virgin female in the cage with the nest. Observe her behaviour for 5 minutes. Place the pups in their home cage in the corner diagonally opposite the nest. Observe the virgin females response to the pups for 20 minutes. If she attempts to injure any pups, remove her immediately and inform the TA. At the end of the testing session, place the pups and some clean paper towel into the clean cage containing the mother and return the family to the colony room.
References:
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