Observations of tail rot in a Northern Territory breeder herd

Introduction

Tail rot is a condition frequently observed in cattle in northern Australia where part of the tail rots away, resulting in a shorter ‘stubby’ tail. While the exact cause is not known, a widely held belief is that it is a result of injury to the tail, such as a dislocation, break or other trauma. It is thought that an injury to the tail may disrupt blood flow to and from the tissue below, causing blood clots to form which can further disrupt circulation. The clotted blood then causes necrosis of the tissues, resulting in gangrene and eventually the tail breaks away (Fordyce et al. 2009). It has also been suggested that infections that impact circulation, such as Bovine Virus Diarrhoea may also be a contributing factor. While tail rot is common in breeder herds, there has been no published data detailing its prevalence.

Methods

The prevalence of tail rot was recorded for 294 Brahmans (BRA) and 247 F1 Senepol x Brahman (F1Sen) mixed-age cows that co-grazed two adjacent native pastured paddocks on Manbulloo Station, NT in September 2018. Cows were managed as two mobs, with 7 and 8 year old cows of both breeds in one paddock and 5 and 6 year old cows of both breeds in the other. Data was analysed using negative binomial regression model.

Results and Conclusions

The overall prevalence of tail rot observed was 3.6% (1.4-5.8% with a confidence interval of 95%). Even though the prevalence was over two-fold higher in Brah (4.7%) when comparted to their F1 Senepol counterparts (2.1%), this difference was not significant (P=0.14; table 1). The prevalence of tail rot was positively associated with age (P=0.01), with the prevalence of tail rot generally increasing by 1.9% per year. The association was independent of breed (p=0.15).

 
Brahman
F1 SenepolCombined breed
TOTAL2944.7%2472.1%5413.6%
Age (years)Number of cowsPrevalence of tail rotNumber of cowsPrevalence of tail rotNumber of cowsPrevalence of tail rot
5812.5%800%1611.2%
6742.75761.3%1502%
71037.8%611.6%1645.5%
8365.6%3010%667.6%

These findings highlight that age is an important risk factor of tail rot and its effect should be considered in the development of future research studies.

Reference

Fordyce, G. Matthews, R and Campbell, G. (2009). Tail rot (necrosis) in cattle. The Australian Cattle Veterinarian 53: 20-22.

Publications

Tail rot: Northern Beef Research Update Conference 2019 Poster (PDF, 4.5 MB)

Further details:

For more information, contact Melissa.Wooderson@nt.gov.au.