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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
Animals with sole ulcers are...
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
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
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)
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
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)
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
What is the biggest reason that hoof disease leads to decreased production?
decreased intake because they don't get up and eat as often
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
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]
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
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)
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
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
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
What is the biggest risk factor for non-infectious hoof problems?
parturition (hormonal and physiological changes)
What nutritional aspects play a role in improving cell/ hoof structure?
adequate vitamins and minerals
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
How much Biotin and Zinc methionine are needed per day?
- Biotin: ~20mg/day
- Zinc met: 200-400mg/ day
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
What are causes of rumen acidosis?
- grain overload
- low physically effective fiber
_________ has a MUCH LARGER role in lameness than __________.
Environment (esp standing surface; rubber vs concrete vs pasture); diet
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)
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)
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
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
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)
How does behavior affect lameness?
older boss cows get more feed and push heifers out of the stalls and get more laying time
What claws of the cow are at highest risk?
back foot, lateral claw