Deaths in wild caught buffalo

CASE A: Deaths of 10 buffalo in one month

Time and location: October 2018, top end NT.

Case definition: Buffalo sit or lie down and waste away over 2-7 days, some having liquid stools.

Disease mapping: Ten out of 400 died within a month of being yarded in preparation for export. While most of the buffalo in the yards were well, a number were mouth breathing and many had pink-purple under bellies (which happens when they are very hot and can’t cool down).

Gross findings: No abnormalities were seen in the post mortem of two affected buffalo. The differential diagnoses were heat stress, nutritional inadequacy, salmonellosis and leptospirosis. Blood, fixed and fresh tissue were sent for pathology, with fresh faeces from two animals.

Laboratory findings: Lab testing ruled out the main differentials (no signs of infections, parasitism or other abnormalities), corroborating the diagnosis of heat stress. The low numbers of salmonella cultured from one faecal sample was regarded as not significant.

Animal / management / environment risk factors: Buffalo were sourced from numerous areas of the flood plains in the NT. Stress from being captured could be contributing to the problem.

Recommendations to the producer: Recommendations were given to manage heat stress: use sprinkler system; don’t over-populate yards, allow animals to spread and have more access to shade; clean the water troughs at least once a day;
and be vigilant and isolate any clinically unwell buffalo.

The following protocols for holding buffalo prior to export were recommended the following protocols to management: Vaccinate against botulism/ clostridial/ respiratory disease before assembly (preferably at time of selection on farm); Provide good access to grass hay and shipping pellets; and as per points given above to minimise heat stress.

CASE B: Deaths of 20-30 buffalo over 5 months

Time and location: Sep-Oct 2018, mid NT.

Case definition: Deaths in penned water buffaloes (male and female) with subacute wasting, stiff gait and serous-mucopurulent ocular discharge. Loss of condition occurs over about a week.

Disease mapping: The buffalo catcher reported that some buffalo left behind at muster had also shown signs of wasting and stiff gaits.

Gross findings: All 5 buffaloes examined post mortem had emphysematous lungs with congestion in the caudoventral areas, and atrophy of the fat around the heart and kidneys. Intestinal segments (duodenum and jejunum) in two buffalo were red and congested. A couple of the buffalo had small circular, necrotic cutaneous lesions on the shoulder, thorax and hip.

The initial differential diagnosis included: cavalcade intolerance – as buffalo are unaccustomed to this feed (this became less likely when second spike of deaths occurred); other causes of enteropathy such as salmonellosis; nutritional deficiencies causing myopathy – such as selenium, Vitamin A, Vitamin E; chronic infection – such as ephemeral fever or bullet/fighting wounds; and possible toxicoses.

Laboratory findings: Notable lab findings were elevated muscle enzymes, degeneration of renal tubules, bile stasis and elevated liver enzymes (but no fibrosis or necrosis), erosive haemorrhagic enteritis and dehydration. There was no conclusive diagnosis.

Animal / management / environment risk factors: Buffalo were caught from the wild, transported to yards and kept in three pens for 1-3 months (depending on export orders). Deaths occurred in all 3 pens of the holding facility. Seems that buffalo held longer tended to be more at risk. Other livestock in the yard, such as cattle and horses, were not affected.