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CHAPTER 2
Behavior Development and Behavioral Disorders BONNIE
CANINE GROWTH DEVELOPMENT
AND
Sensory Development Puppies arrh'c in a \'cr~' C::.1rc-dcp('IH.lent state, with pourly ucvclc)peu llUlllcoslatic Illl'ch· ,nisms. This is gcnerallv recognized by the scaled eyes and ears, bllt these tw·o outward signs act~ally rellect an incompletely dC\'e1oped nen'Ous system as a whole. The progrcssi\"e .1e\'eloplllcnt of the nerVous system can be monitored bv the gain or loss'of certain reflexes, .nd this timing is useful to e\'aluate the normal maturation of puppies. A puppy is horn with lillie spontaneuus mo\"emcnt ano must rcc.:ci'"e stimulation frum the bitch's lieking to begin breathing, irreguLulv at hrst. Inabi!itv to maintain body hcat means that it is important for a pllpp~' to stay close to the bitch and its littermates. Thus, the rooting rellex, which begins disappearing at 4 a..ys, is important (Fox, 1965). \\'ith this reflex, Ihe PIIPPY will orient toward and pllsh iute> allY •....UIl1 object Ilcar its head, and this ''':ann olljed "onl.1 most likely be the bitch or a Iittennate. A I'n ppy will also orien t toward the source of
V,
BEAVER
lieking directed at its hcad and dorsum, IIsillg it as orientatioll to\\"ard its mother. Dllring the first few days of lire:, muscle tone is pourly developed. and lilere prohahly is all imbalance of nerve supply tn the vertebral extensors and flexors. If thc puppy is suspcnded 1)\' holding it at the base of the bead, the PllPPy w'ill respund during the first ,I days of lilt: with the lIexor dominanee reflex, by flexing the spinc, tail, and limbs. From days 5 to 18, the extensor dominallce rencx takes over. so that the PUpP\' ex~cmls the \'ertebral eoluIIII' and limbs. as if starting a baekhend (Fos, 1%5). Continucd parallel '!c\'eloplllellt of the neurOllluscular skills call be followed IlSill).!: other [;\dors
fi)!"
e\"alualioll"
J
II 1II()\"ill~.
pllppic.:s
rcst
their hellies and use strokillg 1l10Vl'llJellls with their limbs on caeh side. Between G and 011
)0 da\'s, the forelimhs can sIIpport the w'eight of the pUPI'~'. Peh-ie limb support is expected between II and J5 days ill normal, lIot overly fat puppies. \\'ithin a few days of being able to support its w'cight, the PUPp\' is walking arollnd its
cl1\"irOlllllcllt.
Allother
4 weeks
bt.Jorc till' I'llI'll!' C;llI riglll ilSI,If. III adult dugs, till' crossed-extl'lIsor is considcred abnormal. I n puppies age of 18 days, tbe crossed-extensor
is
needed l"('SPOIIS{'
be](,re the response 19
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