Maureen Hanson
August 6, 2020
If you’re struggling with a high incidence of lameness in young cows in your herd, you may be trying to fix problems that started before those cows even entered the milking string, according to Nigel Cook, MRCVS, Professor in the School of Veterinary Medicine at the University of Wisconsin-Madison.
Cook told the audience at the recent, virtual Four-State Dairy Nutrition and
Management Conference, that at least two of the “famous five” causes of lameness – foot rot, digital dermatitis (DD), sole ulcers, white line lesions and toe lesions – can have their origins in the heifer lot.
Heel wart woes
“Digital dermatitis is a highly contagious condition, and proliferates in free-stall housing, where animals’ feet continuously are exposed to moisture and manure,” said Cook. He said he has witnessed herds with as high as 30% of their heifers freshening with the telltale DD lesions, often called hairy heel warts.
These dark red, strawberry-like, hairy structures on the heel and interdigital space are extremely painful, and may set cows up for a lifetime of chronic, difficult-to-resolve lesions, leading to constant stress, reduced mobility and lower production potential. Cook shared data showing that about half (45.6%) of heifers that had experienced one DD event pre-freshening suffered from lesions again in their first lactations. First-lactation incidence climbed to about 67% for heifers that had more than one DD episode pre-freshening. In contrast, only about 14% of heifers with no lesions had a first-lactation DD event.
Cook recommended actively monitoring both heifers and cows for evidence of DD lesions, and treating them immediately with topical solutions that recently have shifted from antibiotics to copper compounds and salicylic acid. He also recommended foot baths with the same treatments starting at the heifer stage, particularly in herds in which the heifers are freshening with lesions.
A dry environment and natural footing surfaces during heifer development will lessen the potential of DD becoming established early in life. Cook also has seen positive results in preventing DD by supplementing heifer and cow diets with organic trace minerals, particularly zinc.
Corkscrew claws start early
The other significant foot-health challenge in heifers is the troubling emergence of toe lesions in heifers, associated with a serious hoof malformation called “corkscrew claw.” This condition is the result of unbalanced wear and growth of the front and rear hooves, which causes the outer claw to become non-weight-bearing and the inner claw to carry all of the animal’s weight. Thus, the “corkscrew” appearance of the inner claw emerges, resulting in thin soles and toe ulcers.
Many of the recommended housing guidelines to provide optimum environments for cows are different for heifers. Recycled sand, while an excellent bedding source for cows, appears to be a culprit in corkscrew claw development in heifers. Headlock feeding also causes heifers to push off of their front feet and cause abnormal skeletal changes. Cook’s heifer-housing recommendations include:
Raise heifers on bedded packs when possible, at least up to breeding age.
When free stalls are used, deep-bed with organic bedding versus sand; avoid recycled sand particularly.
Utilize slant-bar or post-and-rail feeders for heifers; limit headlock exposure to breeding and veterinary procedures only.
Improve flooring design for heifers by reducing groove width so that it limits slippage, but does not cause sole wear.
Provide at least part-time access to outdoor feeding and/or pasture areas with natural surfaces.
“We don’t see corkscrew claw problems in heifers raised on pasture or dry lots,” stated Cook. “Providing the right environment early in life will help to prevent the hoof diseases and mechanical issues that can otherwise hamper cows throughout their lifetimes.”
dairyherd.com
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