Agriculture Reference
In-Depth Information
been reported that 5-20% of lameness cases are connected to hoof lesions (Pluym
et al.
,
2013). Hoof rot and infections may originate as an injury from rough flooring but lesions
allow the entry of bacteria resulting in infections, severe pain and clinical lameness. In
general, the most prevalent hoof lesions are on the heel, which is soft and makes up the
largest part of the weight bearing surface. When the outer claw is much larger than the
inner claw, the heel of the outer claw tends to become overgrown and is more prone to
mechanical injuries, particularly on hard walking surfaces. Other major factors that lead
to overgrowth and cracks in the heel area include poor hygiene and rough flooring (Anil
et al.
, 2007). Cracks in the wall of the hooves also occur, both horizontal and vertical
cracks are common and can be associated with lameness. Vertical hoof cracks can be
caused by trauma, some pigs constantly rubbing the wall of the outer claw of back feet in
contact with flooring surface when they are lying down or attempting to rise. Horizontal
cracks are often caused by interruption in horn growth due to vascular compromise in the
corium, and may be caused by endotoxins produced in the gastro-intestinal tract or be
associated with infections caused by Gram negative organisms instead of with a specific
trauma imposed to the hoof. Not all hoof cracks are indicative of lameness. The lesions
of greatest concern are those which penetrate the horn wall into the corium of the foot
and cause an inflammatory response.
18.5.3
Gastro-intestinal
There are a number of serious non-infectious conditions involving the digestive system
that can affect the adult sow including: lesions of the mouth, gastric ulcers, torsions of the
stomach and bowel, and rectal prolapses. Most of the common endemic gastrointestinal
pathogens rarely cause disease in the breeding herd because immunity has been acquired
by the time the animals reach breeding age. Under certain circumstances replacement
gilts are exposed to new pathogens as they enter the breeding herd, for example,
L. intracellularis
(the cause of proliferative hemorrhagic enteropathy) and
Brachyspira
hyodysenteriae
(the cause of swine dysentery). Gilts under these circumstances may
develop diarrhea and become quite sick and possibly die if left untreated.
For the most part adult sows only show signs of diarrhea and/or vomiting if a new
gastrointestinal viral disease has entered the herd or possibly if they have ingested a
poison or toxic substance. The two most common viruses to cause a herd outbreak of
watery diarrhea affecting all age groups including sows are TGE and porcine epidemic
diarrhea (PED). These are both corona viruses, and although unrelated the clinical
signs of the two diseases are similar. Both viruses attack the epithelial cells lining the
small intestine leading to a dramatically reduced ability of the intestine to absorb water
and nutrients and, therefore, causing diarrhea. These diseases spread very rapidly
from pig to pig and from farm to farm by the fecal-oral route. Illness in the sow is
generally mild and lasts only a few days with low sow mortality but the mortality in
piglets can be close to 100%. Sows that are sick with TGE or PED generally go off-feed
and tend to produce very little milk. There is no treatment available, only supportive
therapy including electrolytes and fluids to prevent dehydration. Prevention consists
of biosecurity measures to prevent the introduction of the viruses to the farm, with
particular emphasis on fecal contamination from trucks and fomites such as boots.
