CASE NOTES
WATER, WATER EVERYWHERE AND NOT A SPOT TO STAND
Libby Read, DV Narrabri-Walgett
Posted Flock & Herd March 2011
Introduction
The North West Livestock Health and Pest Authority (NWLHPA) have assisted Industry and Investment (I&I) NSW in livestock welfare responses during floods in the North West, Darling and Central West Authorities since January 2009.
Since the beginning of December 2010, five river systems within the NWLHPA have flooded requiring significant responses. Flooding in these river systems is generally widespread and slow moving. It is not unusual for properties to be partially or fully inundated by floodwaters for many weeks at a time.
This situation has highlighted the need for a set of protocols to be developed that include indicators for assessing livestock aerially and appropriate recommendations to facilitate resolution of livestock welfare situations where livestock will be affected by floodwater for periods longer than several days.
The NWLHPA has developed a standard operating procedure for proactive surveillance and resolution of livestock welfare situations during flood emergencies. The basis for this procedure is presented below.
ASSESSING LIVESTOCK STANDING IN FLOODWATER
As grazing animals, cattle and sheep are most commonly at risk during flood events. Of these, sheep standing in floodwater typically represents the most critical welfare risk.
Assessing the health status of sheep from an aircraft is problematic. It is difficult to draw accurate health conclusions without physically examining animals. During flood events in the plains country of north western NSW, this is rarely possible. Estimations of the health status of sheep standing in water are most often made from a helicopter at a height above tree level. As such, environmental factors, animal behaviour and obvious clinical signs are used to construct a health assessment.
The information contained in Table 1 is based on observations of sheep affected by floodwater in nine flooding river systems in north western NSW. To date, it has not been possible to confirm health indicators via physical examination or laboratory testing. The information represents a starting point for validation as opportunities arise.
Table 1: Factors to consider when assessing the health of livestock in floodwater
| Livestock Health Indicators | Notes |
|---|---|
| Length of time standing in water | It is probable that sheep standing in water for longer than 5 days are at significant risk of their
integument being compromised. This may lead to severe skin and hoof lesions, infections and septicaemia. During a flood event it is critical to research projected river heights and flow characteristics to determine the total likely time period that animals will be standing in water. Animals standing on black soil are more likely to have their integument compromised than those standing on hard, red soil. |
| Dead animals in the vicinity | Poor prognostic indicator. |
| Demeanour | Animals that are bright and alert have a better prognosis. |
| Mob behaviour | Sheep have strong mob instincts. If they are scattered, it indicates a poor prognosis. |
| Avoidance behaviour | Animals making attempts to avoid low flying aircraft have a better prognosis than those that don't. Sheep that ignore a helicopter have a poor prognosis. |
| Mobility | Recumbent animals that don't respond to stimuli have a poor prognosis. The prognosis is good for animals that are mobile. Bogged animals are easily exhausted and have a poor prognosis. |
| Wool length and fleece quality | Sheep in full wool can become water-logged and succumb to exhaustion more quickly than those with little wool. Fleeces with a green tinge indicate wetting for longer than 7 days. |
| Neurological signs | Neurological signs often indicate metabolic disease. Animals showing neurological signs (eg paddling) have a poor prognosis. |
| Injuries | Animals with injuries often have a poor prognosis. |
Figure 1: Sheep showing poor prognostic indicators – not in a mob, recumbent, water-logged and
lacking avoidance behaviour. The clarity of the water indicates prolonged inundation.
Figure 2: An isolated sheep with body flystrike standing in floodwater. This sheep did not react to
a helicopter flying at tree-top level.
Figure 3: Sheep that had been bogged in a black soil cultivation paddock for 3 days.
All showed evidence of exhaustion and neurological disease. There was an inflammatory
line around the coronary bands of their hooves.
RECOMMENDATIONS FOR THE RESOLUTION OF WELFARE SITUATIONS
Recommendations for the resolution of livestock welfare situations involve consideration of the health of the affected animals, the environmental conditions, available resources and the safety of the people involved.
Options include:
Mustering/removal to higher ground with adequate feed
Where possible this is the preferred option. Access paths for retrieval/mustering are determined during aerial surveillance. Mustering options include via quad bike, horse or even by foot. For cattle, mustering via helicopter can be considered. Retrieval can occur via vehicle (quad/4WD/tractor) or via boat. Helicopters can be used to fly stock handlers and quad bikes into the area where appropriate.
It is paramount to consider the health condition of the livestock before recommending this option. Debilitated stock may be unable to move even short distances through mud or water to higher ground.
Photographs of access paths and other landmarks can be particularly useful for landholders to carry out this option.
Figure 4: Cattle being mustered by helicopter to higher ground.
Figure 5: Sheep identified during proactive surveillance, stranded on
an island that was soon to be inundated.
Figure 6: Sheep being forced to swim to higher ground from the island in Figure 5.
Creation of access paths
Cutting a fence or opening gates may alleviate some situations.
Fodder drops
Where retrieval is not possible and stock are standing on an island that will not be inundated, a fodder drop may be the preferred option. The height of an island is difficult to determine aerially unless the helicopter altitude is reduced almost to ground level. Fodder may be provided via vehicle, boat or the air. When recommending this option, the time period for which the animals are likely to be isolated must be taken into account. With sheep, aerial lifting to a more suitable area might be more cost effective than continued aerial fodder drops.
Figure 7: A suitable fodder drop situation.
Aerial lifting
Aerial lifting of sheep from solid ground in cages beneath helicopters can be considered if the sheep are assessed as healthy and likely to survive. Anecdotal reports indicate that aerial lifting of sheep that are already standing in water does not have a successful outcome.
The destination should:
- Be in a location unlikely to be affected by further floodwater rises
- Have adequate access to feed and water (without the need for fodder drops)
- Be accessible for ground monitoring of stock health.
Figure 8: Sheep being aerially lifted from an island.
No action/Continued monitoring
In some cases a solution may not be apparent, the course of action might depend upon uncertain floodwater levels, livestock are identified that will only be at risk if floodwater rises significantly or safety concerns might prevent immediate action.
In these cases the owner is notified and the situation scheduled for monitoring. The time period between monitoring varies from approximately 12 hours to 3 days.
Euthanasia
The decision to destroy injured livestock is made as a last resort. Euthanasia is considered where livestock display a range of the following poor prognostic indicators:
- Standing in floodwater for 5 days or more.
- Severe injuries.
- Exhaustion/debilitation.
- Severe bogging.
- Systemic illness such as neurological disease, septicaemia.
- Prolonged recumbency.
- Full wool, especially with evidence of fleece waterlogging or a green discolouration.
- Poor avoidance behaviour in response to low flying aircraft.
- Scattering rather than mob behaviour.
Where practical and safe, euthanasia is conducted from the ground. Aerial destruction is only considered if this is not possible.
Conclusion
Flooding in the north western region of NSW is a frequent natural occurrence and can affect properties for protracted periods of time. Due to their livestock health expertise, local knowledge, aerial training and access to landholder data (FARMsetc.) LHPA district veterinarians are uniquely placed to assist I&I NSW in resolving livestock welfare situations during flood events.
The information presented in this document is based on observations made since 2009 and represents the basis for an initial protocol for assessing livestock in floodwater and the possible methods of resolution of risk situations.