What are the DIRECT COSTS of lameness when a production-animal - eg., a cow - is lame?
Farm worker's time
Wasted product (meat or milk) due to withholding time
Reduced milk yield
What are the INDIRECT costs of production-animal lameness?
Reduced fertility - takes longer for lame cows to conceive; uterus takes longer to involute; reduced mounting during oestrus; bull fertility reduced
What types of production animals are susceptible to sole ulcers?
Cows and sheep.
What are the two ways of scoring production-animal lameness?
1. Mobility Scoring
aka Dairy Co Mobility Scoring Chart
aka Locomotor Scoring aka Gait Scoring
2. Lameness Records
How is Mobility Scoring conducted? What data is used and what does it measure?
It scores an animal's lameness on a scale of 1 (normal) to 5 (severely lame).
It measurese how many animals are lame TODAY expressed in %
Ie., a snapshot of lameness
This is PREVALENCE.
How do lameness records assess lameness? What data are involved and what does it tell you?
Lameness records are based on both historical & current information, but they can be too subjective or inaccurate as they rely on recording by farm hands, usually, and can be inconsistent.
Lameness records measure how many cases of lameness occurred over a given time period (not a contemporary snapshot) expressed in %.
This is INCIDENCE.
What are some of the key management factors that cause or contribute to production-animal lameness?
Housing- not enough housing or not enough space; unhygienic; not enough lunge space; stocking density too high or simply not enough space for cows to lie down; less than 15% of cows should be standing one hour before milking
Tracks & Gateways - poor surfaces, too many rocks; cows like rubber; maybe too wide - cows like to walk single-file; wet or slippery; should have a foot-bath & trimming schedule; foot-scoring
Feeding - too much concentrate (protein) can lead to acidosis, which contributes to laminitis (poor perfusion of primary & secondary laminae in foot due to opening of pre-capillarary sphincters in AV anastomoses, leading to ischaemia of tissue); concentrate:forage ratio should be 40:60 not the other way around; undermixed food can lead to sorting by cow so it doesn't get enough nutrients; over-cutting of food means it doesn't digest thoroughly, so hay/silage should be at least 2 cm long; overcrowding can reduce intake so there should be at least two feet between cows at feed trough.
What is the Cow Comfort Index (CCI)?
It's the percentage of cows in a dairy herd that are still standing one hour before milking. A CCI under 15% is considered excellent.
Cows not able to lie down long enough or comfortably enough to ruminate (need 11-14 hours per day) & produce enough saliva (up to 150 L/ day containing 3.6 kg bicarbonate) - can cause rumen to become acidotic, which can lead to laminitis.
How do cows differ from horses in terms of where they often experience lameness?
For cows it's often in the distal hindlimbs whereas for horses it's in the distal forelimbs.
What is the pathology of a solar ulcer?
The back of phalangeal 3 starts to press down on the corium, so no horn produced below it, resulting in a hole in the wall.
Sinking of the claw due to activation of matrix metalloproteinase, which is a feature of subclinical laminitis, is the major predisposing factor. As the space between the flexor process of the pedal bone narrows, the corium is crushed, causing ischemic necrosis and compromising horn production. This results in a hole forming in the sole. As the damaged corium undergoes repair, granulation tissues erupt through the hole in the sole. Because this condition is strongly associated with subclinical laminitis, some softening of the sole horn will occur. This increases the rate of horn wear. Softening of the sole horn also occurs under very unhygienic conditions when horn is exposed to the fluid component in slurry.