Cows that are staggering or down are close to being dead cows. A typical beef operation should maintain a less than 1 percent death rate for productive cows. Anything greater should trigger a managerial review to target any potential cause.
The other day, after a nice, wet spring, the alarm went off. Two cows were staggering after a day of sorting and working the cow-calf pairs. Cows shouldn’t stagger, so any indication of instability in a nursing cow is an emergency situation.
The same as having cardiac pads available in human environments, cattle operations should have quick access to a veterinarian for consultation and care in this situation. The two probable causes that came to mind were ketosis (sometimes confused with milk fever at calving) and hypomagnesaemia tetany (commonly called grass tetany or grass staggers). Although there are other metabolic disturbances in cattle, given the setting and time, these two causes came to mind immediately.
Ketosis probably is unlikely because it usually is associated with reduced intake of carbohydrates or more simply, inadequate feed to support the nutritional requirements of a lactating cow. The pastures are adequate but the cows were confined for the work day. Also, there was the added stress of removing cows that had just calved from pasture.
Given the lush forage from recent rains, the more likely problem was grass tetany. Grass tetany must be a concern when the grass is fresh and lush. When the additional demand of lactation is added to the cow, the nutritional requirements and needed absorption of magnesium is critical. Lush grass tends to open the door to an imbalance with other nutritional elements, thus the potential crisis.
The cow initially responds to these metabolic challenges with nervousness and irritability that generally is not apparent to the typical watchful eye. However, due to the rapid onset of the problem, even in well-managed cows, a quick response and treatment is critical. The involuntary contraction of muscles caused by tetany is noticeable to the astute eye, especially when cattle are moved.
Even when challenging a cow to get out of the way, any sign of slight staggering should bring an immediate response when conditions for grass tetany are right. Again, be on high alert when dealing with lush grass, calving, high-milking cows or any management activities that may add stress to the cows and calves.
The other day, the Dickinson Research Extension Center had all the right conditions for the onset of grass tetany. The center just switched to May calving, so the cows were freshly calved and producing good to excellent milk. Recent rains had produced lush grass, so the cows needed to be sorted and moved to native grass. To further complicate the day, rain prevented the cow-calf pairs from being returned to fresh pasture, so they were fed in the lots and returned to pasture the next morning.
If we had a crystal ball, there would have been no clouding. The message would say loud and clear that the potential for grass tetany was there. The additional night in the lots should have declared a further notation: Grass tetany emergency highly probable.
Sure enough, the next morning, the cows were let out to their respective pastures, but two cows showed tetany symptoms and eventually went down. Immediate veterinary intervention was obtained and the cows responded.
The remaining cows where put on high alert and additional pasture inspections were made. Unfortunately, even with the increased observation, one cow died. She was found dead in the morning, so thus the cry of the dead cow.
Unfortunately, cattle monitoring is not an exact science. Oftentimes, due to the predator-prey response, cattle will hide their real feelings during any observation. Metabolic issues are critical and are fatal without intervention.
There always are lessons to be learned. The management team did review and discuss the need for a spring grazing mineral. Providing a mineral with magnesium in the pasture is standard for the ranch.
Next year, the center will continue to provide a mineral but will look for a mineral specific for spring pasture grazing and that has more magnesium. In addition, in consultation with the local veterinarian, all needed supplies will be on hand. One of the two treated cows had early signs of pneumonia on Friday, which was four days after treatment, so follow-up observation and appropriate veterinary care is required.
It’s been a nice spring, but there always is something to keep life interesting.
May you find all your ear tags.