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August 2023
Veld fires are common in South Africa and according to local studies, will increase in frequency over the next three decades. Farmers are emotionally and financially affected by fires, sustaining losses including feed, facilities, livestock and the future performance of surviving livestock exposed to smoke.
The decision-making process about treating animals affected by fires needs to integrate several factors, including the severity of the burn wound and its clinical prognosis, the availability of skilled personnel to care for the animals, adequate shelter, feed and water, the cost of treatment and long-term consequences for their reproductive performance due to smoke exposure.
Offering prognostic hope for moderately burned animals without neglecting their welfare, as contemplated in local legislation, can help mitigate the sense of loss that farmers experience in these situations.
BURN INJURY IN LIVESTOCK – MORE THAN SKIN BURN
Live tissue burns are the most common lesion observed on livestock victims of veld fires. These lesions occur due to direct contact with flames or heat radiation from flames. The management of severe burn lesions is difficult due to the type of care and resources needed, costs involved and the length of the healing time.
A massive loss of fluid and electrolytes leads to shock in animals with partial-thickness burns (second degree) of more than 15% of their total body surface area (TBSA) and/or more than 5% of their TBSA full-thickness burns (third degree). Hence, life-saving intravenous fluid therapy (resuscitation) is necessary in these cases. Moreover, smoke inhalation can severely affect the respiratory system and increase the severity of the burn injury, although it may not be detectable over the first seven to ten days.
ASSESSING ANIMALS, ASSIGNING PRIORITIES
During veld fires the first challenge is accessibility to the affected area, followed by resources to move animals to safer ground. The first approach in such situations would thus be to visually identify animals that would benefit from being moved to receive care immediately, and those that need to be euthanised immediately (first-line assessment). At this stage, injured animals will be mainly evaluated on how they present (comatose vs alert) and mobility (can walk vs can’t rise/walk).
Comatose sheep have been reported to have a hopeless prognosis within the first 24 hours, especially if combined with severe burns on their lower legs and heavy swelling on the head and front limbs. In general, burned animals with an inability to stand and move have been correlated with poor survivability, hence euthanasia is indicated.
It is important to bear in mind that, in most cases, treatment will be done based on veterinary resources available on a mobile setting – this means identifying animals with the best chance of response to treatment is a priority. Thereafter, a more detailed treatment plan can be developed according to the evolution of the patient.
Clinical signs to consider in second-line assessment
The second stage would be to physically examine animals identified as possibly benefitting from treatment intervention. Some will be in burn shock, need intravenous fluid and have respiratory affectation, although this process can take up to two weeks to be evident. Farmers should seek veterinary advice regarding treatment needs to make cost-effective decisions.
EVALUATION OF BURN LESIONS
When evaluating burn lesions, it is important to determine the extent and depth of the burn body surface, which will provide an indication of the severity of the injury and will help in determining the case prognosis.
The following anatomic areas have been defined as percentages of the total body surface: Head 7%, back 7%, left costal wall and left abdominal wall 24%, right costal wall and right abdominal wall 24%, udder 4%, ventral thorax and abdomen 7%, each foreleg 4% (8% for both), each hindleg 6% (12% for both), perineal area 6% and tail 1% – see Figure 1.
The survivability of the animals is associated with the percentage of the body that is affected, and decreases with the extent of the burn wound:
In all cases the survivability substantially decreases with smoke inhalation and critical location burns.
Pay special attention to the location of burn injuries
Burn injuries are commonly found in the face, ears, mouth and lower body (limbs, feet and udder) in ruminants. Sheep not shorn will have wool protecting their skin, but bare areas will be fully exposed.
Movement-restrictive lesions on the limbs, such as affected claws, prompt the need to provide feed and water within reach, and special soft bedding. Moreover, these can eventually be movement-restrictive for the animal due to scarring constriction once healed.
When reassessing animals, those with more than one lost claw should be euthanised, as the condition is painful and prone to fly strike and/or secondary infections. Hence, damage to the legs is an important indicator of the survivability in sheep. However, burned legs in restricted areas not associated with swelling have been reported to heal with appropriate care in approximately 30 days.
Monitoring the body weight is also an indicator of survivability. Endoparasite control in burned sheep under treatment is important, as it can become an added complication due to immunosuppression. Control measures for these ailments should always be considered in the treatment plan.
Cattle feet burns are more serious than in ovine animals. Cattle will not move to eat under these circumstances, hence nursing injured cattle will be a costly and lengthy process. Euthanasia is indicated when the animal shows severely affected limbs and/or no improvement despite treatment, along with a worsening body condition.
Burned udders also need special consideration, as they may be important for future performance.
Mature dairy cows affected by teat burns heal quicker and more satisfactorily, with less anatomic distortion and successful return to normal lactation in comparison to heifers. The healing time for extended superficial burns in adult cows is about four months and usually has a good prognosis, although it needs pain management.
Partial-thickness burns have a poorer prognosis when the time for recovery for subsequent lactation (especially in heifers) is three months or less – bending of the teat and obstruction of the teat canal have been reported as a complication in young animals, which makes the prognosis poorer. Topical treatment with emollients and antibiotics is advocated, and systemic antibiotics should only be used in cases of complications such as mastitis.
FIRST AID FOR BURNS
CONCLUSION
Fires will unavoidably occur more frequently worldwide, hence disaster management preparedness is necessary to contain losses, and a transdisciplinary group of trained professionals should work towards the recovery of the affected community.
Categorisation of burned animals should follow welfare and cost-effective premises, as this is amongst the core considerations in the context of production animals. Case prognosis based on burn severity is only one of the considerations for decision-making, as other factors – such as the location of the burn, smoke inhalation and the availability of resources during recovery – play an important role in the success of the decision. This approach will greatly reduce losses due to mismatching needs and resources in the aftermath of veld fires.
Publication: August 2023
Section: Pula/Imvula
Author: DR CLAUDIA L CARDOSO AND PROF RHODA LEASK, BOTH FROM THE DEPARTMENT OF PRODUCTION ANIMAL STUDIES AT THE UNIVERSITY OF PRETORIA’S FACULTY OF VETERINARY SCIENCE.
