Herd Investigation
Introduction
A study conducted by the University of Liverpool revealed that an important factor in controlling lameness in a dairy herd is the farmer's knowledge on the subject. The first step for a producer would be to use this encyclopedia in order that he/she may be aware of the many factors that can cause lameness.
When to Conduct an Investigation
If 10% of the herd is lame in any given year for reasons OTHER THAN an infectious disease (foot rot, hairy warts, etc.), a problem exists that justifies investigation on economic grounds.
The following are associated with sub-clinical laminitis:
Who should be Involved in the Investigation?
1. The Producer
Whatever the recommendations, it is the producer who must believe in them
sufficiently to implement them.
2. The Veterinarian
There must be a leader who understands all of the implications and who
has sufficient knowledge of the disease process to formulate a control
protocol.
3. The Nutritionist
Correcting one nutritional problem could create another. A qualified nutritionist
should have detailed records and can match nutritional stresses to dates
indicated by the claws.
4. The Claw Trimmer
A properly qualified and experienced claw trimmer should be able to recount
the claw history of the herd from properly maintained records that accurately
define the lesions.
How should the investigation be conducted?
The investigation should be commenced within one hour of the end of morning milking.
Behaviors critical to the well-being of the herd (drinking, lying, etc.) are more obvious soon after milking.
Examine the cows in the loafing yard. Examine the claws of a sample of cows in the milking parlor. Examine the feeds and study the nutrition. Study "cow comfort." Examine the feet of selected animals. Review the heifer-rearing protocol.
1. Examine the Cows Standing and Walking
- Cows may be walking 'carefully' or with hind legs held forward or closer together than normal. This is suggestive of sub-clinical laminitis.
- Some cows may be standing with their hind legs back. This may indicate a sole ulcer or very extensive heel erosion.
- Note how many cows, if any, have puffy feet. Later check how soon after calving this is occurring. There may be an implication that concentrate is being increased too rapidly.
- Swollen hocks, swollen dewlaps and filthy flanks may indicate negative aspects of cow comfort. These may not be obvious later if the producer has prepared especially for the visit.
2. Examine the
Claws of Cows in the Milking Parlor (See
Grooves)
*Not less than ten cows or more than 15%
of the herd
- The claws may be excessively worn, slightly curved and/or low at heel (less than 1.5 inches). This may be a sign of the soft horn produced by laminitic cows.
- A pronounced groove may be located more or less in the same position in 40% of the cows examined. This suggests an insult that took place around the same time from a common cause.
- A pronounced groove may be present at different locations on the claw. Identify the date of insult for each and try to match the timing with some aspect of management at calving.
3. Feeds and the Ration (See Troubleshooting dairy nutrition)
- Physically examine the forage for mold or rain damage. Smell the concentrate for rancidity. Check the particle size of a total mixed ration.
- Check the mode of delivery of the feed to the cows and ensure that there is minimal competition for available resources.
- Examine the analysis of the forages. This is particularly important if forage is purchased off-farm. Sudden changes in the quality of the effective fibre can be disastrous.
- In component-fed herds, carefully check the management of the carbohydrate:forage ratio from two weeks prior to calving until four weeks after calving.
4. Investigate Cow Comfort (See cow comfort)
The investigators are strongly recommended to use the "Britt" table linked from the chapter on cow comfort. Pay particular attention to the criteria noted below.
- Are cows in the holding yard for more then 90 minutes per day?
- Are more than five cows waiting to drink at a time?
- Is more than 15% of the herd standing one hour after feeding?
5. Examine the Feet of Selected Cows
Objective
To check the general severity of the lesions and to confirm the diagnosis of the problem or problems.
Depending on these findings, the producer must be convinced that disease is compromising production and that only by reducing the stress of the animals can a resolution be accomplished.
Ideally the claw trimmer will have been paying regular visits to the farm and also ideally he will have been recording the lesions that he has observed.
This is not intended as a period during which claw diseases should be treated. It is more of an educational session during which the claw trimmer may be reassured of what he may treat and the producer convinced of what should be treated.
6. Review the Heifer-Breeding Program (See rearing replacements)
During routine claw trimming heifers should have their claws trimmed after calving and during their first exposure to concrete. A problem may exist if the claw trimmer identifies an abnormally high percentage of the heifers with severe sole hemorrhages. Health records may show that more heifers are showing signs of lameness than are mature cows. This would demonstrate a worsening scenario which would require very prompt attention.
Conclusions
I do not pretend that a herd investigation is an infallible method of solving a lameness problem. However, with experience, the method can become more and more effective. In my hands, it is the getting together and the free expression of opinions and doubts that works the real magic here. Once a producer understands a problem and accepts a recommendation as reasonable, he/she will experiment in private. It is quite remarkable how many spread the good news to their neighbors.
