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About how thick is the keratinized tissue in a normal hoof?
living tissue should normally be about 1cm up from the sole of the hoof
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Animals with sole ulcers are...
CLINICALLY LAME
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What are common hoof ailments from most severe to least severe? (5)
- [most severe] sole ulcer
- [second most severe] white line disease
- heel erosion, double soles
- [least severe] sole hemorrhage
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If a high proportion of cows are calving in with sole hemorrhage, what questions should you be asking?
what are they doing with these animals in late gestation as far as housing
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Heifers calve in with good heels and no white line disease. 30DIM, these heifers have tripled their incidence of these diseases. Why?
- usually true heifers are housed outside or on a bedded pack- this housing is good for cow's feet
- after calving, the heifers are usually moved into the free stall barn; the increase in heel erosion is almost inevitable due to standing on concrete
- the white line disease is most likely due to the change in diet and social changes (a lot of WLD is caused by physical trauma)
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You see a high incidence of heel erosion in a herd; what is the most likely cause of this?
- heel erosion is majorly caused by wet conditions and standing in manure
- they likely need to start scraping pens more often
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You see a high incidence of hairy heel warts in fresh cows. What is a likely cause of this?
dry cows don't usually walk through a foot bath; heel warts are an infectious disease...consider a dry cow foot bath (logistically would be very hard)
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Describe milk yield losses with hoof disease.
- 1.8-6.1#/day for at least 3 weeks post-treatment
- loss increases with severity
- loss increases in older cows
- loss is greater for abscesses than for warts or foot rot
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What is the biggest reason that hoof disease leads to decreased production?
decreased intake because they don't get up and eat as often
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Why do older cows have greater severity of hoof problems than heifers? (2)
- lesser surface area of hoof per pound of body weight (cows are bigger but their hooves aren't much bigger)--> more stress on hoof walls
- more years living on concrete and cumulative damage to hooves
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What herd factors are related to prevalence of lameness?
- + minutes away from pen
- +++ only trimmed "when needed"
- + trimmed yearly and "when needed" (2x yearly made no difference from 1x yearly)
- - cow comfort quotient
- - brisket board <6" high (too high--> less comfortable)
- - stall base not concrete (more comfortable)
- [note: diet factors played NO ROLE in prevalence]
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Describe how you calculate cow comfort quotient for a farm.
CCQ= (cows laying normally in stall x 100)/ cows that were touching a stall
higher is better
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What are herd factors related to lameness? (4)
- abnormal laying behavior
- mats/ mattresses versus deep bed
- short stalls (uncomfortable)
- thin cows at calving (thinner fat pad)
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What are infectious and non-infectious lesions that lead to hoof problems?
- Infectious: foot rot, hairy heel warts, heel erosions(?)
- Non-infectious: white line disease, sole hemorrhage, sole ulcers
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What are steps that can be taken to reduce infectious lesions? (6)
- clean, dry pens
- proper use of foot baths
- adequate Cu and Zn and consider Zn-met
- biotin (?)
- Modify manure characteristics (?)
- reduce standing time in manure
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Describe modification of manure characteristics.
- [not really realistic BUT]
- a study showed higher incidence of heel erosion for cows on a wet silage diet than cows on a dry hay diet (both diets had same amount of fiber, fiber was very high, so acidosis was not a problem)--> wetter, sloppier manure
- cows also spent more time standing and eating on a wet diet because nutrients are not as concentrated--> more time standing on concrete
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What is the biggest risk factor for non-infectious hoof problems?
parturition (hormonal and physiological changes)
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What nutritional aspects play a role in improving cell/ hoof structure?
adequate vitamins and minerals
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What are the only 2 nutritional substances that are known to have a direct effect on hoof health? What is the mechanism?
- Biotin: helps with keratin synthesis, cell differentiation, and cementing substance synthesis; specific for the enzyme that creates cementing substance
- Zinc methionine: keratin production needs zinc, keratinization of hoof sole is very important for the barrier
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How much Biotin and Zinc methionine are needed per day?
- Biotin: ~20mg/day
- Zinc met: 200-400mg/ day
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Describe the pathogenesis of how subacute rumen acidosis leads to hoof problems.
- moderate decrease in pH--> increase in propionic acid--> goes to liver to synthesize glucose, increase in blood glucose--> insulin release--> excess insulin (for reasons we don't know) causes hoof problems (in horses and pigs too)
- also leads to systemic inflammation due to rumen LPS--> swelling within hoof walls--> compression of blood vessels
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What are causes of rumen acidosis?
- grain overload
- low physically effective fiber
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_________ has a MUCH LARGER role in lameness than __________.
Environment (esp standing surface; rubber vs concrete vs pasture); diet
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What areas should be examined if there is a high incidence of hoof problems in first lactation more than older cows? (4)
- diet transition
- housing transition (going from manure pack to concrete?)
- social transition (group heifers with older cows?)
- heifer rearing (growing heifers too fast is a risk factor)
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What areas should be examined if there is a high incidence of hoof problems in fresh cows more than later in lactation? (3)
- dry cow housing/ comfort
- foot baths for dry cows (not common)
- extreme diet problem (has to be pretty darn bad)
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What areas should be examined if there is a high incidence of hoof problems around ~100DIM? (3)
- transition nutrition
- acidosis issues
- cow comfort/ housing transition
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What areas should be examined if there is a high incidence of hoof problems in late lactation (200+DIM)? (2)
- acidosis issues (diet)
- cow comfort
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How long should cows be laying down a day? What factors affect this?
- at least 12 hours
- how long in holding pen, stocking density, diet too wet (need to eat more), stall design
- pen floor surface (grooves appropriately sized and space)
- cow alley surfaces and flow pattern okay (no sharp turns, deep grooving, etc)
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How does behavior affect lameness?
older boss cows get more feed and push heifers out of the stalls and get more laying time
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What claws of the cow are at highest risk?
back foot, lateral claw
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