Early recognition and treatment of kidney disease in cattle often has a very favourable prognosis. Catching it early is the trick. The capacity of the kidneys is so great that we often do not see any specific clinical signs of disease until two-thirds of the kidneys are already damaged.
There are many causes of toxic damage to kidneys but this article will focus on the infectious causes resulting in what veterinarians call pyelonephritis (pus and infection in the kidneys). The infection results from common bacteria that gain access to the kidneys via the bloodstream. Kidneys are essentially blood filters.
The other means of access is up the urinary tract, and urinary retention from a partial blockage encourages the growth of bacteria that leads to infection.
Kidney infections generally show up in individual animals. Cows with a history of infection from a retained placenta, mastitis, pneumonia etc. are prone to the problem since the earlier infection suppresses the immune function allowing bacteria to gain access to the kidneys.
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 kidneys of a pregnant cow must do double duty, essentially filtering her blood and the fetus’s blood. This taxes the kidneys and leaves them open to infection. The problem is compounded in cows carrying twins.
Any time there is extreme weight loss for no apparent reason you should have the animal checked by your veterinarian. They can palpate the left kidney and the ureter (the tube going from the kidney to the bladder). A urine sample can be checked for blood, bacteria, pus cells and other parameters necessary to rule out kidney infection. Blood samples can be taken to see if the white blood cell count is up.
These tests can catch the infection before it becomes too advanced. Other parameters such as blood urea nitrogen (BUN) only go up once the kidneys are severely damaged. By then the prognosis is poor. My experience has been if cattle are still eating and drinking when kidney disease is diagnosed the prognosis is very favourable with treatment. If appetite has been suppressed the BUN is too high and often in spite of vigorous treatment such as intravenous fluids there is a much lower chance of success.
There are many more cases of kidney infection out there than we realize. This has been made evident to me by the large number of diseased kidneys I have seen when autopsying cows under the BSE testing program. Often both kidneys are 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 stopped eating and died shortly thereafter.
Most of these cows could have been saved and gone on to lead productive lives if caught early enough.
Some of the other early symptoms producers may notice are 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). In cattle there are many causes of red urine from bacillary hemoglobinuria (redwater), phosphorus deficiency to a red dye excreted when cattle are on clover pastures. This can sometimes make a specifidiagnosis more difficult.
Once diagnosed, treatment is a simple matter. The most common bacteria causing kidney infection in cattle is very responsive to penicillin.
There are two keys to treatment. First, the earlier the better, before the kidney is permanently damaged. Second, the length of treatment must be long enough to completely remove the infection to avoid a relapse. At least 14 days, in my experience, will most often avoid relapses. This entails treating daily with procaine penicillin for the first few days until there is noticeable improvement, followed by several long acting shots at the proper intervals for the remainder of the two weeks.
A common mistake is to stop treating animals as soon as their attitude improves and the urine clears. This is a smouldering infection and it will come back if not completely cleared. As with any relapse, the second treatment is much more difficult as the infection has already become deeply seeded.
If an animal remains thin long after treatment it probably has permanent damage to the kidneys. These cattle are like time bombs. With impaired kidney function they are unlikely to reproduce and could succumb to kidney failure at any time. It might be best to cull them before the condition worsens.
Kidney infections occur sporadically 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 animals. Even when labour is included it is a cheap fix.
— Dr. Roy Lewis, DVM
Roy Lewis is a large animal veterinarian in practice at Westlock, Alta.