COLUMNS


Scours in Beef Calves

By Dr. Michael J. Baker


According to the 2011 USDA National Animal Health Monitoring System report "Cattle and Calves Nonpredator Death Loss in the United States," 2010 nonpredator calf losses on beef farms due to scours and related intestinal diseases accounted for 10.4 percent of total losses. This is down from 19.2 percent in 1991. In 2010, herds with fewer than 50 cows had a lower rate (8.3 percent) compared to larger herds, indicating that better prevention and care is being provided.

Regionally, the Northeast is about in the middle of the pack, losing 13.3 percent to scours and intestinal disorders compared to the Northwest, North Central and Southwest regions (14.5 to 15.1 percent) and the South Central and Southeast regions (5.4 to 7.5 percent). The good news is that death loss due to scours has been on the decline, but it still accounts for significant loss. In fact, reducing death loss due to scours by 5 percent is equal to a 5 percent increase in weaning weight. Reducing scours is something you can do now; improving weaning weight by genetics will take 16 to 18 months. Imagine the financial return when reducing scours and increasing weaning weight. Even if the scouring calf doesn't die, research has shown weaning weight and carcass quality are negatively affected. In addition, there are the financial and labor costs of treatment.

Cause

Calves become infected when exposed to infective agents in the environment. Dirty bedding, udders and mud are easy routes of infection for the young calf. Potentially dangerous organisms also occur naturally in the gut. A calf becomes infected when its resistance is lowered by stress, enabling the infective agent to multiply. Every calf is repeatedly and often unavoidably subjected to stress: fatigue of birth, chilling from wind and/or wetness, severe temperature extremes, underfeeding and overfeeding.

The most common infective agents are bacteria, including E. coli, salmonella and Clostridium perfringens; viruses such as rotavirus and coronavirus; and protozoa such as cryptosporidium and coccidia.

Bacteria typically attack the intestines by pumping excess water into the intestines or producing toxins, while viruses kill intestinal cells, thereby reducing absorption. Either way, the result is runny, watery manure known as scours. Note: When handling scouring calves, it is important to understand that E. coli, salmonella and cryptosporidium can cause serious disease in humans; treat all scouring calves with caution to prevent infecting yourself.

There's one other factor related to environment and time. The environment becomes increasingly contaminated as the calving season progresses. This is the concept behind the Sandhills Calving System. Basically, after a group of calves is 1 week old, the cows that have not calved are moved to a clean pasture or paddock. This reduces the risk of exposing 1 to 2-week-old calves, which are most susceptible to scours, to infective organisms being shed by older calves. For small herds this may not be practical, but if scours is a problem, the results of implementing this system have been significant. For more details, visit http://bit.ly/NvSw5W.

Detection

Despite your best efforts, scours will sometimes occur. Calves that are bouncing around the pasture are probably OK, even if they're excreting runny yellow or white manure. Obvious signs are lethargy, droopy ears, slowness in getting up, and a manure-covered tail. Calves that are scouring are dehydrated. If you pinch the skin and it does not go back to normal quickly, this is an early sign. In severe cases, the eyes will be sunken. The nose and eyes might be dry. The temperature of sick calves will often be less than 100 degrees Fahrenheit. Also watch for cows with distended udders, which indicate that they have not been nursed. Keep a close eye on first-calf heifers, as the quality of their colostrum is lower than that of colostrum from mature cows, and their mothering instincts are not as strong.

Treatment

Scouring calves will go down quickly, and if not treated they will die. First, use a rectal thermometer to determine body temperature. If it's below 100 degrees Fahrenheit, the calf must be warmed up before starting therapy. Then, replacing lost fluids is the first line of attack. Most likely the calf will not nurse, so administering fluids via esophageal feeder or stomach tube will be necessary. Warm, balanced electrolytes given at a rate of 1 to 2 quarts three times in 24 hours and up to 4 quarts of warm milk (preferably from the dam, but milk replacer can be used) in 24 hours are recommended. Treatment may take several days.

In severe cases, a saline solution with bicarbonate and dextrose will be given intravenously. Unless you're experienced in this procedure, veterinary assistance will be necessary. Some recommend the use of antibiotics to prevent secondary infection; this should only be done in consultation with your herd veterinarian. A calf coat may protect the weakened calf from further chilling.

Summary

Michael J. Baker, PAS, Ph.D., is a beef cattle extension specialist with Cornell University and a new columnist for Farming magazine.