Originally Posted by
divine
as in the incontinence this has still to be proven to me as i havent had it in a tailess dog in 20 yrs of owning them.JMO
From the Wansbrough report :
DEFÆCATION.
Normally the rectum, anus, and anal canal are devoid of faecal material with the walls in apposition. During
defecation the dog assumes a squatting position with elevation of the tail and subsequent relaxation of the
coccygeus, the levator ani, and the rectococcygeus muscles. This allows the migrating contractions in the colon
to push the faeces distally into the rectum with defecation ensuing. The movement of the tail during the act of
defecation has a direct influence in evacuating the rectum and anal canal of the last part of the faecal bolus. The
coccygeus and levator ani muscles cross the rectum laterally tending to compress the tube, while the recto-
coccygeus shortens the tube. After defecation the muscles return to their normal position with oncomitant
obliteration of the empty lumen. If the tail is removed from an immature puppy the muscles of the tail and pelvis
may fail to develop to their full potential. Removal of the tail in the mature dog may lead to atrophy and
degeneration of these muscles, in addition, if these muscles lose their distal attachments there may be a
lessening of the support and anchorage of the rectum and anus. An absence of adequate function of these
muscles may result in rectal dilatation, rectal sacculation and faecal incontinence.
PELVIC DIAPHRAGM INTEGRITY.
Perineal hernia involves a breaching of the caudal wall of the pelvic cavity with herniation of the rectum, the
abdominal contents or the pelvic contents through an opening bordered by the anal sphincter medially, the
coccygeal muscle laterally and the internal obturator ventrolaterally. Any process resultmg in fascial weakening,
muscle atrophy, or muscle degeneration may predispose to this weakness in the pelvic diaphragm. Often
perineal hernias occur secondary to medical conditions which cause tenesmus with resultant weakening of the
pelvic diaphragm. Burrows and Ellison (1989) recorded a predisposition to perineal hernia in those
brachycephalic breeds, which traditionally have their tails docked, and suggested that inherent conformational
deficiencies may contribute to the disease in these breeds.Canfield (1986) compared long-tailed and docked
Corgis and found that the levator ani and the coccygeus muscles did not develop fully in the docked dogs. A
relationship with perineal hernia potentially exists, but she considered that further research was required before
a categorical statement could be made.
ACQUIRED URINARY INCONTINENCE.
Urinary incontinence in bitches caused by urethral sphincter mechanism ncompetence (SMI), is a multi factorial
condition. A recent study (Holt and Thrusfield 1993) noted the increased risk of SMI developing in large breeds
but it also concluded that bitches belonging to small breeds had a reduced risk and medium breeds had no
increased risk. Breeds identified in this study as having significantly increased risk of developing SMI were the
Old English Sheepdog, Rottweiler, Doberman Pinscher, Weimaraner and Irish Setter. A reduced risk was
demonstrated in the labrador retriever, and, although the result was not statistically significant, a low risk was
observed in the German shepherd. This agreed with the observations of Arnold et al (1989).Holt and Thrusfield
(1993) noted 2 consistent association between SMI and tail docking which they interpreted as an indication that
docked breeds of whatever size are more likely to develop incontinence than undocked dogs of the same breed.
It is well recognised in women that the risk of developing genuine stress incontinence (GSI) is related to pelvic
floor muscle damage during labour. In the bitch the equivalent 'pelvic floor' muscles are the levator ani and
coccygeus muscles both of which attach to the tail base, and it is possible that these muscles are atrophied
and/or damaged in docked breeds reducing urethral resistance. A similar relationship may exist between tail
docking and submissive urinary incontinence in puppies.Holt and Thrusfield (1993) conclude that their results
provide some evidence to support the arguments against tail docking and that it would be interesting to
determine if the predisposition to urinary incontinence in currently docked breeds such as the old English
Sheepdog and Doberman Pinscher would be reduced if they cease to be docked.