Bovine Health: Why do cows die?

Death loss on dairies is always concerning to the producer and management team. There are obvious financial losses as well as public perception of animal welfare challenges. Every cow or calf death on a dairy should tell us something. In order for it to tell a story, it needs to be properly recorded. The cause, or suspected cause, of death should be identified as well.

Do you have a problem? The value in recording death loss on dairies is to see if you can find meaningful trends, therefore allowing meaningful interventions. Every cow and calf death must be recorded. Even if the cause is unknown, the comment should be added to the herd management software so the veterinarian and other consultants can understand what is happening.

So what are reasonable goals regarding death loss? The most common benchmark for adult cows is less than 5% annually. The benchmark for calves 24 hours to 60 days old is less than 3%. Goals should be herd specific and attainable.

What are the reasons? It is critical to ascertain trends involving cow and calf deaths. Calf deaths are typically fairly predictable, with diarrhea and pneumonia involved in the majority of cases. Adult cow deaths can be much more variable, ranging from transition cow diseases, mastitis, injury and/or herd outbreaks of certain diseases such as Salmonella.

Sometimes it is not acceptable to simply make the excuse “The weather is hot, and we have cows dying from mastitis.” Understanding what is causing mastitis, or other disease for that matter, is the first step in preventing the next case. As an example, in the case of severe mastitis, don’t assume it is caused by E. coli and there’s not much you can do. Occasionally Klebsiella or other pathogens can be involved that require different management steps to control.

What are steps to reduce death? Deaths of cows and calves are inevitable; however, many deaths can be preventable if proper steps are taken. Again, determining trends in causes of death is a critical step to this prevention. One common reason for cows to die is injury. This can sometimes be accepted as normal and not considered preventable. If cows are being severely injured, have you ever thought about the underlying cause? Are people trained well enough in how to properly move cows? Are the barn floors or holding pens slick? Where are cows falling? Is there a particular area where cows are being injured?

Another common cause of death is mastitis. There is certainly an acceptable level of mastitis to be expected in a dairy herd; however, death due to mastitis should be minimal. If mastitis deaths are occurring with frequency, there are questions that should be asked. Have mastitis cases been cultured to determine the cause? Has the vaccine protocol been reviewed to ensure gram-negative mastitis prevention is adequate? Have milkers been recently trained in proper technique? Are bedding protocols being followed? Are cows clean? If not, how can cleanliness be improved.

These two examples should give an idea of the types of conversations that should occur when trends in death loss start to appear.

What are the steps to monitor? Recording death loss should occur after every death event. The frequency of monitoring of death rate is largely dependent on the size of the herd. Larger herds will be able to glean meaningful data fairly frequently simply due to a larger sample size of cows. In smaller herds, where death is more infrequent due to less cows, it may take several months to really gauge if death loss numbers are improving or not. It may also be valuable to look at year over year data due to seasonal fluctuations in death loss.

Death of cows and calves should not be accepted as normal. Record and investigate the causes. Better results help the bottom line of the business, and also help improve the industry’s public perception.

by Gabe Middleton, DVM

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