This paper is an attempt to record some details about a local fire and the subsequent injuries to female cattle. A review of the available Australian literature found little detail about observations that farmers and stock assessors considered 'common knowledge,' in particular the suitability of some surviving female heifer calves as future commercial beef breeders. Examination of heifer weaners 5 months after the fire found that a number that were not culled at the time of the fire had healed, but would now be unsuitable as commercial breeders due to teat damage.
On December 17th 2009 two grass fires caused extensive damage to property and livestock in the Hume Livestock Health and Pest Authority. A Section 44 was declared for both fires and Emergency Operation Centres were opened.
One fire started at approximately 12:50hrs at Ournie in the Upper Murray. (4) Under the influence of a strong westerly wind, it burnt rapidly eastwards through undulating grassed and timbered country to Tooma.
The conditions on the day of the fire were classed as extreme. Weather observations made at 15:00 hours at Tumbarumba were; 12% humidity, temperature 37C, Average Wind Speed and direction 39km/hr WNW and 44Km/hr NNW with gusts to 85km/h at Khancoban. (4)
The bulk of dry feed in the early summer pasture meant that there was significant height and heat to the fast moving flames. Trees in its path were scorched to their full height, or burnt.
In the Ournie- Tooma fire 2972 sheep and 640 cattle were burnt or destroyed due to the fire. 190 head of cattle were sent to salvage slaughter. 2547 sheep and 4202 cattle were sent away on agistment. Approximately 11,500 hectares were burnt. (4)
Cattle affected included joining mobs of cows with calves at foot, and joined first calf heifers.
Cattle and sheep were assessed by attending veterinary practitioners, LHPA veterinarians and Victorian DPI staff. Advice was given based on past experience and using the NSW DPI Primefact 'Assessing bushfire burns in livestock', ( Rast L. 2006) and Victorian DPI Agnotes AG1371 'Assessing Sheep after a Bushfire' and AG13701 'Assessing Cattle after a Bushfire' as standard references.
Animals were destroyed, sent to salvage slaughter, sent to agistment and some were treated. The assessment process continued for 7 days and involved revisits from LHPA veterinarians to monitor burnt stock.
The fire caused quite extensive burns to some of the surviving adult cattle, including face, ears and up the side of the body to the top of the pelvis.
An opportunity arose in April 2010 to survey surviving females on affected properties at Ournie and Tooma in an attempt to quantify the losses due to the Ournie/Tooma fire. By this time, females that were calves at foot during the fire had grown to weaners.
Female calves may not have been identified as having significant udder damage during assessments at the time of the fire. If they had clinical evidence of burn injury (e.g. singeing, superficial burns) but were mobile, bright, alert and feeding they would not have been culled at that time.
The survey project was complicated by several factors. Individual animals were not identified at the time of the fire. By April 2010 property owners had often grouped fire affected stock with animals not exposed to fire into one management mob. Not all animals that had been exposed to the fire could be identified individually in these management mobs. For the purpose of the survey all females on an affected property were examined by the private veterinarians.
This limited the amount of hard data that could be collected and analysed. At the start of the project we examined some animals known to have been burnt to set some parameters. There were 3 mobs with a good history of fire exposure that we examined initially.
There was an opportunity to examine a line of 150 weaner heifers from a badly affected property in which all calves would have been exposed to fire to some degree.
On 4th May 2010 the group of 150 weaner heifers were yarded and individually caught in the head bale to be examined in the crush. Initially animals were drafted randomly. There was a group of females with clinical evidence of healed burns to the perineum or face and ears that could be picked out in the yard from the larger group. These were selected for examination from the larger group.
The teats were described in three categories as 'having no gross or palpable abnormality', 'uncertain', and 'grossly abnormal'.
We found that we couldn't be confident on some heifers as to whether we were seeing subtle burn scarring, or physiological immaturity. There were animals where the teats appeared uniformly of a normal size and shape, but the orifice was not clearly visible. We described these teats as 'being soft, pliable, with a teat orifice apparent but reduced and flush to the skin surface, with no slight indentation' and classed these initially as 'uncertain'.
Teats that we classed as 'No apparent gross abnormalities' were described as 'having a soft pliable long conical shape, no palpable fibrous tissue, apparently patent teat orifice with a slight indentation over the orifice and no changed pigmentation or gross scarring.'
Teats that we classed as 'grossly abnormal' were described as being 'fibrosed, no teat orifice apparent, and teats could be shortened, misshapen, blunted or absent.'
Of the 150 heifers available, 77 were examined that day in a biased sample. Results were that 49/77 had no gross abnormality, 8 were classed as uncertain and 20/77 heifers were classed as having grossly abnormal teats.
We recommended that those with gross abnormalities be culled as fats and designated unsuitable for breeding. The uncertain group we recommended be re-examined as more mature cattle. The group with no apparent abnormalities we recommended to be monitored at pregnancy testing and/or calving.
We noticed a clinical correlation between evidence of ear burns (loss of tissue or abnormal skin) and teat damage in this group. Of the 20 heifers with grossly abnormal teats, 17 had clinical evidence of burn injury to the ears and face. Three others appeared clinically normal but on examination had damaged udders.
Some adult females that had been nursed after the fire were also available for examination on the same property. They were restrained individually in the head bale and examined in the crush.
2 cows and three 2008 drop heifers that had been nursed for body and facial burns were examined. Although skin burns had healed, all had damage to teats affecting patency and were considered unsuitable for further lactations. It was recommended these be culled to slaughter.
A smaller sample group of older heifers was also examined on another property with confidence that all had been exposed to the fire. They were caught in the head bale and examined individually in the crush.
11 first calf heifers that had just been joined in December 2009 were assessed as culls to go to salvage slaughter at the time of the fires. Their injuries had included burns to the perineum and as high as the hips.
This cull did not take place and this group were available for assessment in May 2010.
9 of the 11heifers, now in calf, had gross teat lesions including totally ablated teats, shortened and blunted teats, teat canals with absent teat orifices or teats with fibrosed orifices and poor milk flow.
Heifer calves at foot during the Ournie -Tooma fire were found to be at risk of receiving burn injuries to their udders and teats that rendered them unsuitable for commercial reproduction.
Some adult lactating cows and older heifers were burnt badly enough in the udders to require culling at a later date even if they survived the fire and the initial assessment.
The apparent link between facial burns and udder damage was not able to be consistently repeated during the survey that followed. It was possible to have teat damage without clinically apparent evidence of previous burn injury present elsewhere on the body.
While not a means of detecting all damaged teats, we concluded that selecting those with physical evidence of facial burns could be a reasonable place to start an initial draft.
In the LHPA we rarely have an opportunity to re-examine stock at a later date after a fire. Our work focuses on the immediate emergency and its impact on livestock. Any follow up nursing is left with the owners and under the supervision of private practitioners.
The survey commissioned of the local private practitioners allowed a unique opportunity to follow up and record some sequelae to burnt udders that would impact future reproductive efficiency in female beef cattle.
We had some difficulty initially in assessing variations of normal teat conformation and referred to some dairy literature to gain an appreciation of the variety of morphology that could be considered normal. (1, 8) The beef animals were surprisingly homogenous.
In our work we rely on Government publications for guidelines when assessing burnt livestock. There does not appear to be a great deal published to record the kind of injuries to livestock caused by bush fires in Australia, and what is available covers a range of climatic and environmental conditions and classes of stock. (2, 3, 5, 6, 7, 9)
Morton et al. reported that milk in the udder of dairy cows seemed to have a protective effect from fire and that springing dairy heifers had a high risk of subsequently developing mastitis.(7)
In the Ournie- Tooma fire we were dealing with beef cattle rather than dairy cattle, and heifers in early pregnancy. These beef heifers had difficulties with teat patency that could be identified and dealt with well before calving, not the problems with mastitis reported in the dairy heifers. (7)
Lactating cows with burnt udders had difficulties raising calves at foot. The culling process left calves without dams and cows without calves. It was observed during the survey work that growth rates in some calves had been affected.
Bushfires do not occur regularly in the same place and under exactly the same weather conditions. The effects on livestock can be highly variable depending on the class of stock impacted, the fuel load, the timing of management procedures and weather conditions on the day.
We were fortunate that the wind dropped on the night of the 17th December 2009, allowing the fire to be brought under control.
Thanks to David Hall and Chris Miller for involving and assisting us in this project, David Hall for his excellent photographic record, and to those producers who allowed us to go through their cattle one by one.