By Dr. Rob Tremblay
Down dairy cows, or ‘downers’, are not common but they are a challenge to deal with for dairy farmers and veterinarians. Downers can be a lightning rod for tension when they don’t respond quickly to nursing care and get up.
The causes of downer cows are quite varied, anywhere from injury to metabolic disease. One key to making good decisions about downer cows is to try to get a better understanding of why the cow is down. A recent report from the veterinary school in St. Hyacinthe, Quebec, listed what caused cows to be down when they were brought to the veterinary school. The large animal hospital at the school offers flotation service, so they tend to see many down cows. Between 1995 and 2014, they admitted more than 1,100 down cows. They ended up using a flotation tank to assist all but about 150 of those cows. Just about 50 % of the cows survived. This is about twice as many cows that were observed to recover in a recent study from Australia.
Many of the non-survivors at St. Hyacinthe had serious injuries that would have made recovery difficult or impossible. It pays to have downer cows examined by a veterinarian to see if the reason the cow is down is an injury that cannot be successfully treated. Cows that have damage to the nerves that control their legs or have injuries like dislocated joints are much less likely to stand again. It is best to investigate what is wrong so you can make better decisions. Cows that have mastitis or metritis, but have no injuries, are much more likely to recover.
The Australian study reported that one of the biggest predictors of whether downer cows would successfully stand again was the quality of the nursing care they received. One good reason that so many cows survived at St. Hyacinthe is likely the quality of care. The Australian researchers also found that cows that were down for longer than 24 hours carried a lower probability that they would eventually stand up and be productive again. That finding was pretty much the same as a study of U.S. dairies. They found that cows down for longer than 24 hours were three times less likely to become productive cows again.
The welfare research group at the University of British Columbia recently investigated downer cows too. They had access to a flotation tank owned by a local veterinary clinic. They also concluded that good nursing care improved the chances that a cow would stand again.
What are the take homes from all this research? Well, first it is good to try to figure out if the cow is injured. Then, it is important to provide nursing care right from the start. That would include addressing any metabolic abnormalities including dehydration, and providing a protected, dry and well-bedded area with good footing. Cows that are repositioned frequently, including using flotation tanks, are also much more likely to recover.
The following are some of the components of good nursing care as listed in the Australian Veterinary Journal.
Treatment: Have the cow appropriately treated for the primary cause of the recumbency (being down). Then appropriately treat for any secondary conditions.
Location: Down cows should be cared for in a small, sheltered area within a shed or barn. For cows that are unable to stand but can walk after being lifted: Keep them away from slippery surfaces. Isolate them from other cattle. Lift them once or twice daily and closely monitor them.
Bedding: Use deep, soft bedding of suitable material: 40–50 cm of hay, straw or 20–30 cm of sawdust, rice hulls or sand or appropriate depth of equivalent substrate.
Cow only to be lifted in these circumstances: The cow is able to take some of its own weight after being lifted and not hanging from the lifting clamp or within the frame. Or the lifting is supervised by the care provider so the cow can be lowered when observed to be no longer standing effectively.
Use barriers to restrict cows crawling more than two to three metres. Use barriers to prevent cows from crawling off the suitable bedding. Cows that are unable to change sides by themselves should be rolled off the down leg several times daily. Offer the cow access to good quality feed at all times. Provide suitable drinking water. Do teat disinfection twice daily. Milking is optional unless leaking milk. Protect the cow from adverse weather conditions, including excessive cold and heat.
Dr. Robert Tremblay is a veterinarian for Boehringer-Ingelheim and lives near Guelph.