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This article was published in 1982
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Report on Mortality in Calves
J.A. Macfarlane, B.V.Sc., Veterinary Inspector, NARRABRI
'If a job's worth doing, it's worth doing badly' (O. Wilde)!
SITUATION
2000 hectare property North West of Narrabri on the black soil plains. Of this about 1100 hectares is dry land farmed for agriculture every year.
WEATHER & PASTORAL CONDITIONS
Weather for 1981 was generally hot and dry. There was significant rain in May resulting in germination of burr medics and winter annuals e.g. turnip weed. This dried off early following the dry winter and spring. Further rains fell in late September and through October. Although some Mitchell grass germinated and regrowth of existing plants occurred the main bulk of feed is summer annual herbage e.g. yellow vine, pig weed, roly poly, along with some summer grasses.
LIVESTOCK CONDITION & MOVEMENT
1. Sheep: Border Leicester stud of about 300 ewes.
2. Cattle: At the end of 1980, cattle consisted of 96 cows with first calf. 54 of these were all that remained of the owners herd after the drought, and 42 were purchased from a local cattle herd. Cows were re-joined April 1980. Four (4) bulls were used although only two at any one time. Due to poor seasonal conditions (made worse by the fact that the cows were first calf heifers) fertility was low and only fourteen (14) calves were born in January 1981. Calving continued throughout the year and the owner decided on all year round joining until seasonal conditions improved.
The cattle were moved to agistment in May 1981 to allow some pasture growth following the rain (by which time there were 32 calves) and returned in mid June (by which time there were 54 calves). The first crop of calves were now weaned and 30 remained as steers on the farm all year.
STOCK DISEASE & LOSSES
Late September, early October: Cattle were in top North West paddock which has a long boundary with a cotton farm.
On 7.10.81 a dead calf was taken into the local practitioner for post-mortem.
The history was given as follows:
26.9.81
Two (2) 3-4 month old calves were found dead and had been for a day or two.
28.9.81
One calf 3-4 months old noted standing reluctant to move with nasal and oral clear discharge, trembled when disturbed and died within 24 hours.
7.10.81
A calf was presented dead to the local practitioner for post-mortem with similar clinical signs, with evidence of diarrhoea as well.
Post-mortem - only finding consisted of petechial haemorrhages on abomasum and heart.
Laboratory findings - fresh and formalised samples forwarded to the laboratory were unrewarding, 'it was not possible to offer a diagnosis in this case.' Unfortunately brain was not sent. Practitioner suggested S.B.E. based on history (and certainly it was common at this time in this area), with the alternative of a poisoning of unknown origin (not unreasonable especially next to a cotton farmer of questionable spraying practices).
The owner rang a few days later and it was suggested to move his cattle away from the cotton farm, (to avoid any possible chemical poisoning) and treat all sick calves with Terramycin (for S.B.E.).
On the 15.10.81 the owner again rang stating two (2) more calves were found dead (making the total 18 ex 65 at this time). I visited the property and ascertained the following:
Clinical signs of the sick calves were basically similar although there was some variation.
Calves were restless and trembled or shivered when disturbed. Later they were reluctant to stand at all. Some nervous signs of wandering aimlessly, apparently blind and head pressing were seen. Some were seen to stand in the dam although animals generally were not significantly pyrexic. There was excessive salivation and lacrimation and nasal discharge. A grey coloured, foul smelling watery diarrhoea was present to a variable degree.
Many were just found and nearly all died within 24 hours.
of the two (2) calves found dead on 15.10.81 one was about five (5) months old and the other three (3) days old, Both had been dead some time before post-mortem.
Post-mortem - Intestinal lesions, some intestinal congestion, no evidence of peritonitis. Liver was pale.
Thoracic lesions - some petechial haemorrhages on heart walls.
Brain - some congestion.
Laboratory Findings - similar to before.
Bacteriology - no significant organisms.
Histopathology - basically related to congestion and autolysis.
Comment - poisoning or exotic disease.
The owner went on two weeks holiday, sick of the whole business and left it to his neighbour to contact us if any further problems arose.
I rang him a week later and he said 'Oh well, you've got to have stock to have losses!'
On 30.10.81 (Saturday morning) the owner returned and reported that while he was away:
Five (5) 3 - 5 month old calves and two (2) young calves had died, making a total of 25 now dead.
Two aged cows died while he was away and he had a further two (2) sick calves, and a sick bull.
The sick ones were about three (3) months and one (1) week old, with similar symptoms to the others. I collected serum, E.D.T.A.. samples, blood slides, nasal and eye swabs, faecal samples.
The bull was obviously suffering the after effects of a disagreement with one of his counterparts.
Of the samples the laboratory did not return, no significant findings were noted.
The cows were moved again to the South East end of the property adjoining a T.S.R.
The Veterinary Inspector went on two weeks leave sick of the whole business. On 12.11.81 one Lee Cook visited the property and reported:
Another ten (10) calves had died, mostly much younger (i.e., about 2 - 10 days) with similar signs and the diarrhoea was now the most pronounced sign. Old mate (the bull) had also thrown in the towel. Serum E.D.T.A. samples, smears and plants were taken.
Laboratory findings:
blood samples from two (2) suspect calves - within the normal range
'smears' in keeping with an inflammatory reaction although the sites of the collection are not clear
plants - unsuitable for identification
virology results - not yet to hand.
At this stage Lee Cook and I decided it was time to co-ordinate investigations and arrangements were made to transport sick calves to Armidale and other places (various), agronomists were going to check for poisonous plants, samples were going to Lismore, Rydalmere etc.
The owner checked the cattle three (3) times daily for two (2) weeks and no sick calves were noted.
No further mortalities or sickness have since been noted.
CONCLUSION
A total of thirty five (35) calves died between 26.9.81 and 12.11.81. The clinical signs were similar but not specific with an age variation of about two (2) days to six (6) months, with mostly younger calves dying towards the end.
The cause of the mortality remains unknown.