4 minute read
Herd Health
Early recognition and treatment of kidney disease in cattle can often have a very favourable prognosis. The capacity of the kidneys is great, so often we may not see any specific clinical signs until two thirds of the total kidneys’ capacity are damaged.
There are many causes of toxic damage to the kidneys but this article will focus on the infectious causes of kidney disease resulting in what veterinarians call pyelonephritis (pus and infection in the kidneys). The infection results from common bacteria which gain access to the kidneys from the bloodstream. Kidneys are essentially blood filters. The other area of access is up the urinary tract and urinary retention from partial blockage will encourage growth of bacteria and infection. Kidney infections are generally individual animal problems and cows may have the history of a prior infection from a retained placenta, mastitis, pneumonia etc. These infections suppress the immune function and allow the seed of bacteria to gain access to the kidneys.
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In cattle one of the very first clinical signs is weight loss. I see more of these cases in late pregnancy or right after calving. The pregnant cow must essentially filter both hers and the fetus’s blood. This taxes the filtering ability of kidneys, which is why this is the most common time to acquire kidney infection. Cows carrying twins have this problem compounded. Any time there is extreme weight loss for no apparent reason, have the animal checked by your veterinarian. They can palpate the left kidney and the ureters (tubes going from the kidneys to the bladder). A urine sample can be obtained and checked for blood, bacteria, pus cells and other parameters necessary to rule in or out kidney infection. Blood samples can be taken and the white blood cell count may be up. Other parameters such as blood urea nitrogen (BUN) only go up once the kidneys have been severely damaged and by then the prognosis is very poor. My experience has been if cattle are still eating and drinking well and kidney disease has been diagnosed prognosis with treatment is very favourable. If appetite has been suppressed the BUN is too high and often in spite of vigorous treatment like intravenous fluids prognosis is very poor.
There are many more cases of kidney infection out there than we realize. This has been made evident to me by the large number I have seen when autopsying cows under the BSE testing program. Both kidneys will be severely infected and have very little normal function left. The common history is the farmer noticed weight loss but no other symptom and then the cow quit eating and died shortly thereafter. Most of these cows can be saved and go on to lead productive lives if caught early enough. I am sure a number of these cows died on producers’ farms with no diagnosis prior to the BSE testing.
Producers may notice increased frequency of urination or pain at urination. Look closely at the urine, especially at the end of the urination process for signs of pus or blood (red coloured). This will provide a clue kidney infection may be advancing. In cattle there are also many causes of red urine from bacillary hemoglobinuria (redwater), phosphorus deficiency to a red dye excreted when on clover. All these and many other causes of red urine can sometimes make the specific diagnosis more difficult.
The most common bacteria causing kidney infection in cattle is very responsive to penicillin. There are two keys in treatment. First the earlier the better before more permanent kidney damage is done. Secondly the length of treatment must be adequate to completely clear the infection to avoid a relapse. Treatment periods for at least 14 days, in my experience, most often will avoid the relapses. This most definitely will entail treating daily with procaine penicillin for the first few days until there is noticeable improvement. Then several long acting shots the required days apart will stretch treatment out to the two weeks. A common mistake is stopping treatment too early when attitude improves and the urine clears. This is a smouldering infection and will come back if not completely cleared. As with any relapse, the second time treatment is much more difficult as the infection becomes deep seeded. If the cattle remain thin long after treatment there has probably been permanent damage to the kidneys. These cattle are like time bombs and with impaired kidney function are unlikely to reproduce and could eventually succumb to kidney failure. They might be best being culled before the condition worsens.
Kidney infections are sporadic occurrences across the prairies. Every herd experiences them from time to time, but with careful observation, early intervention and correct treatment the results are often gratifying. Penicillin is still a very effective drug as it is concentrated and excreted through the kidneys and subsequently the urine. Let’s try and treat more of these conditions as they are – even with labour included – a cheap fix.
