By Heather Smith Thomas – The most common illness in young calves is cattle scours (diarrhea). There are many causes, including intestinal infection because of bacteria, viruses, or protozoa. Whether calves get sick depends on multiple factors such as exposure to pathogens, poor immunity, and/or stress. Good weather, clean ground, and stress reduction — shelter from bad weather and minimizing confinement — helps reduce the incidence of cattle scours.
There are two important strategies in scours prevention — helping the calf become more resistant to the pathogens, and trying to reduce the number of pathogens the calf is exposed to that cause cattle scours.
Boosting immunity starts with adequate colostrum for newborns. There must be a high level of antibodies in the cow’s colostrum and the calf must suckle enough colostrum, very quickly after birth, to be adequately protected. Pregnant cows can be vaccinated for common pathogens that cause cattle scours. If vaccinated a few weeks before they start calving, the antibody level in their colostrum will be highest. For viral diarrheas like rotavirus and coronavirus, and for E. coli bacteria (all of which tend to affect calves early in life), the vaccines work fairly well. Calves are then protected if they ingest enough colostrum soon after birth.
Make sure the cow is in good body condition before calving, so she can produce the best colostrum. If cows are too thin, they don’t produce adequate colostrum. As a rule, first-calf heifers’ colostrum is never quite as good because they haven’t had as much chance to become exposed to as many things or build as strong immunity as an older cow.
Many people think vaccination can prevent all problems, but it should just be the icing on the cake after other good management strategies. There are many reasons a cow’s immune system might not respond to vaccines and this is why body condition is important. A healthy animal in good condition can more readily mount a good immune response. Also, the calf must obtain colostrum quickly, to get the necessary immunity. Calves born to thin cows may not be strong, and slower to get up and nurse.
Even if you vaccinate the cow so she produces protective colostrum, this has no benefit if the calf can’t or doesn’t nurse enough or soon enough. The tricky question is whether calves got enough colostrum soon enough. This varies, depending on exposure to pathogens. If cattle are out on grass, it may not matter so much.
If you need to give a calf colostrum (if he can’t nurse for some reason), it should be as much colostrum as possible and as fast as possible. This means about six pints in the first six hours (preferably within one to two hours of birth) and another six pints in the following six hours. You can use frozen colostrum or some from another cow, or milked from the calf’s own mother. Second best is a commercial colostrum replacer.
Preventing exposure is the other part of the battle, making sure the calving area is as clean as possible. You don’t want cows in a wet, sloppy environment where they have manure all over their teats. It’s always a race between pathogens and the antibodies in colostrum, regarding which gets to the gut first. If the calf is trying to suckle a dirty cow, nuzzling her brisket or flank or a dirty teat before he latches on, pathogens get a head start in this race.
Calve in a different area than where you wintered the cows. A new cattle pasture will be cleaner, with less contamination. There are various strategies, such as the Sand Hills system where people keep moving the herd to clean ground. You move the cows to a clean calving area just before calving, then keep moving the ones that haven’t calved — every two weeks — to new pasture, away from the ones that have already calved. Then there’s no manure buildup or calf scours in the new area. If you can keep the youngest calves from being exposed to older calves that may have already been sick, you prevent problems.
If you are still feeding hay and using bale feeders, move them frequently so cows aren’t standing in manure. Moving feeders or changing location of your feed-ground every day can help keep cows and udders clean.
Cattle scours outbreaks are usually because of heavy loads of contamination. Calves may become sick even if cows were vaccinated and calves obtained colostrum. If the weather is bad and calving areas are muddy and dirty, the pathogen level may be so high that the calf’s immunities are overwhelmed.
Some diseases like coccidiosis, salmonella, or cryptosporidiosis can’t be prevented by a vaccine. Keeping calving areas clean, and preventing exposure to manure or animals that may shed these pathogens, are the main ways to protect calves. When tubing sick calves, clean and disinfect equipment between calves. Shelter and bedding are also important to reduce stress and keep calves clean and dry. If you use shelters, keep the bedding clean, and move shelters frequently to clean areas.
If a calf gets sick, treat early. A calf will recover much faster if you can treat him before he is dehydrated and weak. Giving fluids is crucial, no matter what the cause of the diarrhea. Dehydration is generally what kills a calf that dies from cattle scours. If you can give enough fluids to prevent or reverse dehydration, the calf stays stronger and is more able to fight off the infection.
If cattle scours occurs in the first week of life, antibiotics may be needed, since it’s likely because of bacteria. If calves are older, it’s common to have scours caused by a virus or a parasite such as cryptosporidia. When calves are three weeks old or older it might be coccidiosis. With these causes, antibiotics do no good and fluids are the best treatment.
It won’t help to just give pills or boluses. A dehydrated calf won’t benefit from those; he mainly needs fluid and electrolytes. If calves can stay with their mothers and continue nursing occasionally, this will be adequate to provide energy. If he’s weak and not nursing, use an electrolyte product that contains energy.
Most labels recommend giving electrolytes twice a day. That may be fine in some situations, but if a calf has severe diarrhea and is losing a lot of fluid and electrolytes (especially a very young calf), it’s better to give fluid/electrolytes four times per day, every six hours. Give fluid by tube; electrolytes don’t taste good and the calf will refuse to suckle if you try to bottle-feed fluid — especially a calf that isn’t feeling well and off feed anyway.
Sick calves may be helped by anti-inflammatory medication. If a calf is miserable and you want to keep him nursing, a non-steroidal anti-inflammatory drug like Banamine can help. It only takes a small dose for a young calf. This can help him feel well enough to keep nursing and not become so weak and dehydrated, recovering faster, with fewer treatments. Some types of diarrhea are more painful than others. With certain types of enterotoxemia (toxin-forming bacterial infection in the intestine) calves may have acute gut cramping and pain relief can be a huge factor. Pain medication may also help a calf with coccidiosis if he’s constantly straining because of the irritated intestine and rectum.
Discuss treatments with your local veterinarian on a case-by-case basis.
Oral or IV Fluids?
Oral fluids, given often enough, can reverse dehydration unless the calf has gone past the point where he can absorb fluids through the gut. If he becomes too dehydrated, the gut shuts down. A rule of thumb: if the calf can still stand and walk, give oral fluids. If he is too weak to get up, has poor suckle reflex and can’t raise his head, he needs an IV. At that point he is going into shock; he’s lost so much body fluid that blood volume is low. The gut can’t absorb fluids because the body is trying to get blood to vital organs instead. You won’t save the calf without an IV; take him to your vet immediately.
Signs of serious dehydration include lethargy and weakness, sunken eyes, and cold extremities. If the calf is gaunt and eyes are sunken, he probably needs IV fluids. If the calf is not responsive, becoming weak and cold, he definitely needs an IV.
What illnesses have you had to deal with when raising calves?