Today, I talk about abortions in cattle; but let me first respond to two questions from farmers, emanating from two recent articles.
One farmer notified me that I had provided valuable information that triatix or amitraz does not kill fleas but I never advised on the recommended chemicals for killing fleas.
The troublesome insects are killed by products of various chemical groups. Pyrethrins are natural pyrethrum insecticides that are effective against fleas and have very low toxicity on other animals and humans. However, they are highly toxic to fish, lobsters and oysters.
I recall a client who sprayed her cat with pyrethrins next to her open fish aquarium. All the fish died from contamination with the insecticide.
Organophosphorus chemicals are effective against fleas but can also be toxic to humans and animals if improperly used. They can reach poisonous levels in the blood if ingested, inhaled or absorbed through the skin. Cats are particularly sensitive to the chemicals.
Use of the chemicals in the species is not recommended. I have treated many cats poisoned by the chemicals even in very small quantities.
Another group is pyrethroids. These are the synthetic forms of pyrethrins. They are much more potent than pyrethrins. Right mixes with water should be used to avoid poisoning the animals. Poisoning by the chemicals has no specific antidote.
Carbaryls also kill fleas and they are mainly used in powder form. They are often used to dust birds, the animals’ living environment and animals where one may not use liquid insecticides such as animals with multiple wounds.
Finally there is fipronil and closely related phenylpyrazole chemicals. These are mainly used as skin application or swallowed. Therefore, there are enough choices of the chemicals one can use to kill fleas in animals.
I have avoided to give specific commercial brands of the insecticides because I cannot list all of them and would not wish to be construed to be promoting some brands.
We now return to the question of why cattle abort. I visited a farmer in Ruiru last week to flush the uterus of a repeat-breeder cow.
Once I finished, the farmer told me there was a cow which appeared to have some pink tissues protruding from the vulva but was not due to calve down.
The problem had started in the morning but there had been very little progress in discharging the pink material. According to the farmer, the animal had not strained and was eating well. It also had not been visibly sick.
On examining the cow, I found it had normal vital parameters comprising mucous membranes colour, body temperature, heartbeat, breathing rate and rumen contraction.
There were some fluid-containing membranes protruding from the vulva.I confirmed the animal was aborting. From the records and observation of the placenta buttons called cotyledons, the cow was about three months pregnant.
Further, the cow was not straining but the uterus kept contracting gently to evacuate the contents of the pregnancy.
From the observations, I concluded the foetus had died three to seven days earlier and was now being expelled together with the uterine fluids, placenta and its membranes.
I decided to leave the cow to complete the abortion without any interference in order to minimise the chances of injury to the uterus and infection. A major clinical policy is to not interfere with any natural process if it is progressing well on its own to avoid introducing complications.
I advised the farmer to monitor the cow and inform me if the abortion would not have been complete by the following morning. I would then return to the farm to help the cow complete the abortion.
The farmer asked me what could have caused the abortion and what causes abortions in cattle. She also wanted to know if other pregnant cows in the herd would abort.
To start with, the history of the aborting cow had absolutely no information on possible causes of the abortion.
The cow had been inseminated artificially and hence infection by the semen was unlikely.
As to whether other cattle could abort, it was again not possible to tell or speculate.
I only consoled the farmer that most pregnancies are uneventfully carried to term.
Finally, I addressed the question on why cattle abort. The risk of abortion is always there wherever there are pregnancies. There are many causes of abortions. They may be due to physical injury of the mother and foetus as occurs in falls, fights, rough vehicle rides or squeezing through hard narrow spaces.
With physical injuries, the foetus may be damaged to death or the foetal membranes may be damaged to a level that compromises blood and nutrient flow to the foetus.
In most cases, once a foetus dies, it is rejected by the body and expelled from the uterus.
In some cases, the foetus may be incompatible with the mother and the uterus rejects it. Death of the foetus due to extreme malformation may also cause abortions. Abortion investigation is usually more successful when a number of animals in a herd are affected.
