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Livestock Welfare INSIGHTS Issue 1 - June 00
SUMMARY OF FIVE STUDIES
A COMPARISON OF DAIRY CATTLE TAIL DOCKING STUDIES
Tail docking of dairy cows is a management practice, seen as a means of ensuring udder health, cow cleanliness and ease of milking.
The procedure is usually done with a constricting rubber ring applied 4 - 6 inches below the vulva, causing the end of the tail to die after about a week.
Many tail docking studies have been carried out on dairy cows to determine whether the procedure is justifiable on food safety, animal welfare or milker comfort grounds. Some recent studies have been summarized below in an effort to compare study methods, purposes and results.
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U of BC
(Cassandra Tucker,
et al) |
U of Guelph
(Dr. Ian Duncan,
et al) |
New Zealand
(Dr. L.R. Matthews,
et al) |
USDA
(Dr. Susan Eicher,
et al) |
Mississippi State
(Dr. D. Pogue,
et al) |
| Tie- stalls |
- |
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- |
 Fly count |
- |
| Free-stalls |
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- |
- |
Pain Study |
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| Rotary shed |
- |
- |
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- |
- |
| Docked (D) |
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| Non-docked (ND) |
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| Switch docked |
- |
- |
- |
- |
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| Switch shaved |
- |
- |
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- |
- |
| Sample sized |
500 total (end count 344 D, 132 ND) |
64 total (16 D & anesthetic, 16 D & no anesthetic, 16 ND & anesthetic, 16 ND & no anesthetic |
56 (end count 41 total, with 15 D, 16 switch shaved, 10 ND) |
16 cows - cleanliness & fly count, 20 calves-pain study 21 cows-pain study |
Could not access |
| Incidence of Mastitis |
No difference |
- |
Sample size too small |
N/A |
N/A |
| Cow cleanliness |
No difference |
- |
N/A |
D cows cleaner |
N/A |
| Somatic cell counts |
No difference |
No difference |
No difference |
- |
ND>D |
| Fly count and agitation |
N/A |
ND>D |
ND<Switch shaved<D |
ND<D |
No difference |
| Pain/stress reaction to tail docking |
N/A |
Few signs of pain in D cows |
N/A |
Variable |
- |
| Milk Yield |
N/A |
No difference |
No difference |
N/A |
D>ND |
| Anesthetic use evaluated |
N/A |
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N/A |
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N/A |
| Main Purpose of Study |
Cow cleanliness, udder health |
Pain |
Milker comfort, cow health, welfare, production |
Pain, fly counts, cow cleanliness |
Milk quality, and production, fly counts |
| Overall Results |
No cleanliness or udder health benefits found with tail docking |
Few signs of pain from docking, but increased fly avoidance and agitation, study ongoing |
No difference for milk yield, somatic cell counts. More fly avoidance for D cows |
Measures of pain were variable, D cows show > fly avoidance |
Somatic cell counts higher in ND cows, fly counts no difference, study ongoing |
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| Docking studies offer conflicting results |
| Sample size and testing for statistical significance may account for the discrepancies between Mississippi's findings compared to British Columbia and New Zealand. The Mississippi study presented its findings as cumulative averages, but did not apparently test the statistical significance of differences for somatic cell counts and milk yields. Sample sizes were limited in many studies, which makes conclusions difficult.
The New Zealand study found very few occasions where the tails of cows were in contact with the milker. However, parlor design may have affected these results. With cows increasingly being milked from behind, contact with the tail would likely increase.
Pain studies have been difficult to base conclusions on. The USDA study found that here was some indication of a stress response from cows after tail docking (haptoglobin levels increased in adult cows, but not in calves).
Behaviourally, calves were noted to show signs of stress. In the study done at University of Guelph, behavioural signs of stress were absent in adult cows. Behaviour indicators of stress may not be appropriate because many species have adapted to not visibly exhibit their pain as a survival tool against predators.
The University of Guelph study also measured cortisol through saliva samples, but these have yet to be fully analyzed.
Conflicting results were obtained regarding cow cleanliness between the University of British Columbia and the USDA. The USDA study had a small sample size, which may have contributed to his difference.
From the above studies it would seem hat justifications for tail docking in dairy cows are limited to milker comfort. Tail docking is likely not acceptable from an animal welfare perspective.
Perhaps a report that reviews multiple tail docking studies and compares their methods and results could give us more information on which to base an informed decision on the appropriateness of tail docking in dairy cows.
Photos from UBC dairy tail docking study.
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Recommended Practices for Tail Docking in Dairy Cows
The American Association of Bovine Practitioners (AABP) recognizes that more work is needed to fully understand the welfare, food safety and milker comfort implications of dairy cattle tail docking.
It encourages research studies that use scientifically valid methods with clinically relevant outcomes reported in peer-reviewed publications.
Until consensus can be reached, the AABP recommends that, if tail docking is to be done, it should be as young as practical using appropriate techniques.
(From the AABP Position on Tail Docking in Dairy Cattle and email communication with Larry Hutchinson, D.V.M., AABP President).
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