Monitoring the suckle reflex in calves

Some recent research has revealed a test that easily predicts which calves should receive supplemental colostrum at only a few minutes old.

It was the result of some work by Dr. Elizabeth Homerosky, a veterinarian at the faculty of veterinary medicine at the University of Calgary, as she was comparing various testing procedures to determine weak calves. These may be calves that are simply weak at birth, ones that have undergone a hard pull, and even those that underwent a delayed calving and are possibly anoxic at birth.

Of all the tests she looked at, the most predictive in terms of weak calves was coincidentally the easiest to do: assessing the suckle reflex.

All it involves is inserting a couple of fingers into the mouth of a newborn calf 15 minutes after it is born to determine how vigourously it can suck.

We’ve all done this and can attest that many of the calves we end up tubing often have a very poor suckle reflex.

It’s not a complicated test. The reflex is either vigourous or weak. The result is usually fairly obvious and when in doubt I would call it weak.

These are the calves that should be given supplemental colostrum, as they are likely slow to rise and thus slow to nurse. Essentially the suckle reflex determines their vigour and when one is questioning whether to give supplemental colostrum it makes that decision extremely easy.

The rule on many farms is any assisted calves get colostrum. The reasoning is the cow is already caught so it only takes a few minutes to milk her in a good maternity pen and you are then assured the calf has adequate colostrum early in life. If the birth has been harder than normal or delayed, start checking the suckle reflex on these assisted births and see where they stand.

Some calves are simply vigourous enough that even with a harder pull they will rise quickly, but generally speaking the harder the pull the slower the calf is to rise. In these cases non-steroidal anti-inflammatory drugs prescribed by your veterinarian can help.

If you consistently check your calves within 15 minutes of birth it will be easy to identify the sluggish ones. The beauty is we now know partial failure of passive transfer accounts for many of our problems down the road and if we can go one step further to eliminating this, then great.

It also helps that there are some excellent colostral products out there today such as Headstart from the Saskatoon Colostrum Company. Make sure and read the label to know how much immunoglobulin you are giving the calves as not all colostrum substitutes are created equal. You want to get a minimum 100 grams into them early. Then you need to determine whether the colostrum substitute or natural colostrum will provide the entire source, if you figure the mother will still provide a percentage with her fresh colostrum.

When checking the suckle reflex use latex gloves or wash your hands well before and in between checks. You don’t want to be the main cause of unwanted organisms being spread between calves. For much the same reason we need to clean our esophageal feeder every time it is used, especially the oral tube.

By identifying weaker calves easily we can administer colostrum and provide other treatments early enough to enhance calf survival. The suckle reflex test is easy for producers to do, has no cost associated with it and relies on their own skilled judgment.

There are a few cases where we can still be fooled, such as calves that appear vigourous but don’t rise because of a bad back or other developmental issues.

Then there are calves born to cows with large coke bottle teats who gain little colostrum even with vigourous suckling. There are always a few calves born to cows with blocked or scarred teats or those who simply don’t produce enough milk. When in doubt, supplement.

Calves suffering a partial failure of passive transfer of immunity at birth are more susceptible to diseases like scours and pneumonia. It starts with these calves and then spreads to others in your herd. I guarantee, if we all start to check the suckle reflex it will be time well spent. When you think it will only really take a few seconds to accomplish, it seems a small effort to gain a healthier calf crop.

It’s hard to understand why it took so long for someone to document a strong vigourous suckle reflex with a more vigourous and, ultimately, a healthier calf, but I’m glad Dr. Homerosky pursued this investigation.

Now we all need to develop our own treatment plan so we’re prepared to act when we encounter a slow suckle reflex. If in doubt, try comparing these calves to healthy ones in the same herd and you will soon become expert at determining those calves that need a little more TLC, which must include colostrum.

Have a great spring and hopefully we can end up with fewer sick calves than in past years.

About the author

Contributor

Roy Lewis is an Alberta-based veterinarian specializing in large-animal practice. He is also a part-time technical services vet for Merck Animal Health.

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