Small Mammal Anatomy 2

Small Mammal Anatomy 2

1. Reproduction

   • Duplex Uterus
     • Many rodents
     • Right and left uterus and cervix
     • Open into common vagina
     • Others have bicornuate uterus
   • External Genitalia Rodents
     • Male - rounded scrotum at caudal end. Lots of fat around testes with longer anogenital distance
     • Female - more pointed caudal end with shorter anogenital distance
   • External genitalia Rabbits
     • Male - scrotal sacs either side of preputial sheath and a circular genital opening
     • Female - triangular vulva, slit like genital opening with thoracic adn inguinal mammary glands
     • Both have hairless patches lateral to anus containing inguinal glands
   • Reproductive systems - Ferret
     • Male - similar arrangement to dog. Os penis has curved tip - catheterisation difficult
       • Often castrated or vasectomised to take jills out of season
     • Female
       • Similar anatomy to cat, oestrus cycle linked to increased daylight in spring
         • Coitus induced ovulation, if unmated oestrogen production continues leading to hyperestrogenism leading to post oestrus anaemia through surpression of bone marrow
       • Gestation - 42d, 4-14 kittens with 6-8 weeks weaning
     • M = hob; Mn (Male Neutered) = Gib; F = Jill; Fn = Sprite

2. Respiratory

   • Rodent/Lagomorph
     • Larynx is in high position in oropharynx meaning they must breathe through nose meaning that respiratory disease is rapidly debilitating
     • High oxygen demand - lungs not proportionally larger therefore low residual lung capacity
       • Greater number of alveoli with a smaller diameter - 200um in cats whilst 45um in syrian hamster
     • Poor lobulation of lungs in rabbits therefore pneumonia can spread very fast.

3. Cardiovascular system

   • Heart large in proportion to thorax with heart rate of 180-300+ BPM
   • Blood volume is 60-75ml/kg
     • Can't take 10ml of blood from a 100g hamster, you'll kill it. Take this into consideration
   • Venupuncture
     • Saphenous/Cephalic veins are small
     • Tail Vein

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