Vet on call: Ignore washing cattle against ticks at your own peril

Friday July 10 2020
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Beatrice Inyange watches as her dairy cows graze in a farm in Elburgon, Nakuru County. When animals are vaccinated against lumpy skin disease (LSD) some of them may still come down with mild disease due to insufficient development of immunity. PHOTO | JOHN NJOROGE | NATION MEDIA GROUP


Two weeks ago, I got an interesting call from a fellow professional – Dr Kamau from Kiambu. Interestingly, he is also a farmer with about 50 dairy cattle, which he treats when sick. 
There was a lumpy skin disease (LSD) outbreak on his farm and he thought he was on top of it until the affected cows started dying.
He explained that the LSD did not appear very serious since he had vaccinated the animals for the year. 
The nodules on the skin were small-sized to moderate and did not overlap in what we medically call coalescing. 
In severe infections, nodules will normally be large and fuse with each other, making the skin look generally swollen. Such animals look very ill and their temperature rises above 41 degrees centigrade.
Dr Kamau further told me his infected cows would eat well but at some point, they would start salivating. 
The animals would then stop eating altogether, became dull and die. The last dead animal had a lot of froth in the airways.
I questioned the farmer about treatment and he explained he had used the recommended antibiotic and anti-inflammatories. 
To that level of briefing, I was convinced the doctor had done the necessary treatment, but then, mild LSD does not kill cattle or even stop them from eating. Froth is also not found in the airways.
When animals are vaccinated against LSD, some of them may still come down with mild disease due to insufficient development of immunity. 
Out of the 50 cattle, only five had shown the infection. They were recovering well until the new development. 
Two weeks had elapsed since the last case. It, therefore, meant that the other animals were likely to be fully protected from the disease.
Now, the big question was why some of the infected cows were coming down with a complication that had already killed two. 
Dr Kamau requested me to visit his farm. I found all the affected animals on the farm were pregnant heifers. 
Fortunately, none had aborted. LSD may cause abortion due to elevated temperature. The anti-inflammatories given had worked well to maintain the temperature just above normal at 39.9 to 40.5 degrees centigrade.
The first thing I noticed in the pen with the sick animals was pelleted droppings. Two of the animals answered my inquiry by voiding normal dung. The farmer and his workers had not identified the cow that had voided the unusual dung.
I examined the less sickly cows first. They had a fever of 39.9 and 40.5 degrees centigrade and reduced feeding. 
They were also slightly salivating. The external lymph nodes were all heavily swollen - a finding expected with LSD infection. 
I took a blood smear sample from the cow with the higher temperature for laboratory examination.
The sickliest heifer had a temperature of 40.6 degrees centigrade. It was very dull and had not been eating for the past two days but was drinking water.
The eyes were beginning to sink into their orbit. The rumen was stagnant and the heart had a loud pounding beat. 
I could also pick the heart beat from a wider than normal chest area. Breathing was a bit laboured and shallow. It had more salivation than the other two.
I did rectal examination and encountered pelleted faecal material. Such an occurrence happens when a cow has a blood parasite called anaplasma that causes the disease anaplasmosis. 
The disease lowers intestinal and stomach movement, causing hardening and pelleting of the dung to look like donkey droppings.
The lymph nodes of the last heifer were enlarged to the size of a medium-sized mango. There were no bleeding spots on the gums. 
I took a blood sample smear to later examine in the laboratory. The blood of this cow was thinner than normal. The finding corresponded with pale mucous membranes of the eyes and gum.
From the clinical examination findings, I diagnosed possible complication of LSD with diseases spread by ticks.
Back in the office, I found the two cows I had examined first had east coast fever (ECF) in the early stages. 
Their red blood cells had small blue dots that signify the parasites. The sickliest cow had both ECF and anaplasma parasites.
The anaplasma parasites were responsible for thinning of the blood. To defend itself, the body destroys red blood cells that contain the parasites. 
As the disease progresses and more cells are destroyed, the blood becomes watery and the mucous membranes become pale due to low blood supply. Destroyed blood cells are converted into bile that is stored in the gall bladder.
Towards the terminal stage of the disease, the bile produced is too much and it fills the gall bladder. 
Excess bile remains in the blood and causes the mucous membranes and urine to turn yellow. Animals in that stage have poor to low chances of recovery.
I informed Dr Kamau of the findings and advised him to treat all the animals for the combination of tick-borne infections I call “the three musketeers”. They are ECF, anaplasmosis and babesiosis. They can quickly exterminate your cattle especially when they come in combination.
From my experience, Dr Kamau’s case evaded easy detection because of two main reasons. First LSD and ECF both cause fever and swelling of external lymph nodes. 
Therefore, Dr Kamau was hoodwinked by the obvious signs of LSD. When ECF set in, the lymph nodes could not swell any further. 
Second, the tetracycline antibiotic that Dr Kamau used at the beginning of the infection suppressed ECF parasites but it is known not to kill them. When the infection re-emerged, it did not have all the signs of the disease.
Tetracycline treats anaplasmosis fully. That would explain why the first two cows had no anaplasma parasites in the blood. 
The third cow must have got infected with anaplasma parasites after the drug had already cleared from the system.
I advised treatment for the three musketeers because when one of the parasites is detected, it is likely that the animals are exposed to the other two.
Dr Kamau regretted having stopped washing his animals weekly against ticks. It is the best way of controlling the three musketeers. He had argued that his cows were safe since they were fully zero-grazed.