1. The strain or race -the environmental factors such as Ii-temperature,light,season,etc Nutrition Social factors

2. The stage of development where the animal reaches sexual maturity -the opening of vagaina in the female -the descent of the testicle in the scrutum in the male Laboratry animals are mated for the first time shortly after the signs of puberty

3. From puberty onwards, the genital tract in the female undergoes a series of cyclical and repetitive transformatios called estrus which consists of four phases called, proestrus, estrus,meestrus, and diastrus The length of the cycle varies from one species to another

4. It is important for the animal breeder to know when the animal is in estrus phase, since it is then that she can be fertilized -she is receptive to the male -ovulation takes place Spntaneous induced

6. During psuedogestation the female is not receptive

8. -the biological features of the species -the type of the animal required -production requirment Permanent mating, the female is not separated after parturition 1. 1.monogamous 2. 2.polygamous 3. Temprary mating 4. 1.polygamous or harem type 5. 2. monogamous

9. timerabbitGuinea pigratmouse Weeks weeks 6-7 5-6 8 10 6-8 5-8 6-7 5-7 Age at puberty Male female Weeks weeks 6-7 5-6 10-1211-128 6-8 Mating first Male female days12-1616-194-5 Length of cycle 12-16 days6-15 hours9-20 hours7-20 hoursLength of estrus hours10-13 after mating 108-112-3 hours after beginning of estrus Time of ovulation After parturition _3- 8 hours28 hoursWithin 28 hours Postpartum estrus

10. days31-3262-7221-2319-21Length of pregnancy 7-939-1110-12Number of young per litter 6-8 weeks14-25 days21 days16-21Length og lactation years1-4 5 4.5 1111 1-1.5Length of fertile period Male female grams6490-1005-6 gr1-1.5 grAverage weight at birth

11. 1.1 puberty -female, opening of vaginal at 28-49days -male maturation of spermatozoa at 45 days

12. 4 to 5 days and depends on 1.Strain 2’social environment The estrus lasts 7-20hours

13. An estrus occur 14 to 28 days after parturition

14. Spontaneous ovulation Takes place 2-3 hours after beginning of estrus

15. Check the vaginal plug. Remains 16-24 hours -to know dated embryo -cesarean cases

16. Non suckling female Hybrids have a shorter period of gestation Suckling female If the number of suckling is 1-2 gestation is prolonged 7 days If the number is more than 3 the gestation is delayed by 12-16 days

17. Lasts 11 days Common in female grouped together

18. Takes place at any time Three and a half hours foe a litter of 11

19. lasts 4 weeks Milk is high until 10 days Tput the male in separate cages -during weaning never put more than 30 hey eat solid food at 14 - make sure weaning takes place at 21 During weaning never put more than 30 animals in one cage -

20. The first mating 6 to 8 weeks Mice should not be paired off after the age of 12months Breeding animals sacrificed 12 -18 months Permanent mating most often used One male to two to six female

21. 2.1 puberty Female vaginal opening48 to 60 days Male testicle descend 40 days

22. The female rat has a cycle of 4-5 days To detect the estrus -use the vaginal smear -observe the behaviour of animal -hyperactive -hallow back

24. Vaginal plug eliminated very quickly

25. 3.1Puberty Female: the vagina is usually covered by an epithelial membrane which disappear during estrus and parturition The first rupture of vagina membrane takes place at age of 58 days and the first estrus 68 days Male: 68 days

26. Average length 16 days depending on the strain and individual, the onset of estrus is as follow

27. Vaginal plug is not always present

28. Average 68 days Litter of 5,67

29. The new born are very advanced in age The pubic symphysis dilate 24-to 36 hours the pubic symphysis is 17- 22mm

30. 3-5 animals: 75-80 g 1 animal: 140 g -sacrifice the animal whose birth is below 50gr

31. 21-28 days When they reach 170 – 180 gr -separate male from female

32. Males: 10 -12 weeks Female 12-14 Female weighing 400 gr with male of 500 gr

33. a. Unit comprising 1 male and 4-6 female b. Units comprising c. 10 females to 1 male

34. The females are not separated from the mating unit

35. 4.1 Puberty -small breed 4 months -middle breed 4-7 months -large breed 9-12 months -male:6-7 months

36. 12-16 days -the vulva is congested -the female is agitated -ovulation takes place 10-13 hours after stimulation

37. Female if receptive adopts a hollow back posture -the individual -the physiological condition -circumstances Males quickly falls

38. 31 to 32 days

39. Psuedogestation last 16 to 17 days

40. -making the nest -food consumption drops -delivery takes 30 minutes, sometimes hours or days