– Dr. Michelle Arnold, UK Veterinary Diagnostic Laboratory
Every year, the UKVDL receives calves that died suddenly in the first week of life, usually with few or no symptoms. Often the owner will describe the situation this way: “calves will nurse, be 2-3 days old and found dead” or “calf was 3-5 days old, lying around more than normal and nursing very little, found dead the next day”. At necropsy (an animal “autopsy”), the pathologist will find no milk within the calf’s digestive tract. Further laboratory testing will find bacteria can be grown (cultured) from several organs such as liver, kidney and lung. These deaths are diagnosed as “septicemia” which means the calf died from an infection in the blood (usually a Gram negative bacteria such as E. coli along with the “toxins” or poisons the bacteria produce) that damages all the major organs of a calf, resulting in death. Affected calves respond poorly to antibiotic treatment and those that survive often develop one or more swollen joints. These calves are also at greater risk for diseases such as diarrhea, pneumonia, and meningitis in the coming months. Most grow poorly and die prior to or at weaning. The question is often asked “what should I have treated this calf with to save it” but the real question that needs to be addressed is “why did this happen in the first place and how can I prevent it?”.
Preventing septicemia and other neonatal calf diseases like scours begins long before birth of the calf. Excellent cow nutrition during and after gestation, a quick calving process, and biosecurity management factors to decrease environmental contamination all contribute to a successful start. The following list of management practices are crucial to calf health.
- Don’t allow pregnant cows to lose weight during gestation. The dams’ diet must provide adequate energy, protein and trace minerals to meet her needs during gestation and lactation, especially during cold or wet winter weather. Remember up to 80% of fetal growth occurs in the last 50 days of gestation and cows are also producing colostrum during the final 4-6 weeks of pregnancy. New research has identified the role of “fetal programming of the immune system” during pregnancy as a major factor affecting calf vitality after birth. In fact, the latest research has proven there is no safe time during gestation to “short” a cow of her nutrient needs (including trace minerals) that will not impact the health of her unborn calf. A nutritionally deprived cow will produce poor quality and quantity of colostrum, have less energy to deliver her calf quickly, and she can lose a substantial amount of weight during her lactation so she will be slow to rebreed. Calves born to energy deficient dams will have less of the brown fat needed for energy to stand and nurse.
- Don’t wait to assist a cow or heifer having difficulty in labor. If a cow or heifer is in active labor for 1-1.5 hours and making no progress, calving intervention is indicated. Assist with calving as early as possible, especially with heifers. Don’t hesitate to call for help if you don’t know what the problem is, if you know what the problem is and what the solution is but you can’t do it, or if you have been trying to correct the problem for 30 minutes but have not made progress. EARLY INTERVENTION IS KEY to saving a calf and the dam.
- Colostrum is key to calf survival. Make sure calves start nursing after calving, keeping in mind that calves should stand within 30 minutes of delivery and nurse within 30 minutes of standing. If in doubt that the calf will be able to stand and nurse within an hour, the producer must take over to ensure the calf is warm and then use a good quality colostrum replacer (not a colostrum supplement) or milk the dam and feed the calf at least 2 quarts during the first 6 hours of life. Most septicemic calves had inadequate colostrum intake, either because the dam did not produce enough good quality colostrum, or the calf was unable to suckle enough to provide good protective immunity. In either case, this situation is called “failure of passive transfer of antibodies” or “FPT”. The calf may be born weak and does not get up quickly or nurse aggressively, however, FPT may also be due to bad teat conformation (shape) and the calf simply could not latch on or reach them. Other factors that impair calf immunity include lack of calories (dam provides little or no milk), selenium and copper deficiencies present at birth, and lack of protection from harsh weather.
- Don’t calve out cows in a mudhole. Poor sanitation, cold, wet weather and overcrowding in calving areas also contribute to a higher risk of disease. Septicemia in calves is most often the result of a bacterial infection acquired around the time of birth. The bacteria may enter the newborn through several routes including the navel (umbilical stump), through the mouth or nose, or through an open wound. Calves born in dirty, muddy, manure-covered areas such as around hay rings or in a run-in shed have a wet, exposed navel cord lying in contact with massive numbers of bacteria as soon as they hit the ground. Once the calf gets up, mud or manure-covered teats provide the next opportunity for bacteria to enter the neonatal calf. Even with adequate colostrum, the immune system can be overwhelmed by the sheer numbers of bacteria, viruses and parasites in the environment. Newborns produce little gastric acid during the first week of life which makes them especially vulnerable to infections that enter through the digestive system. If cows are dragging their udders through mud to reach feeding areas, move to a new area with good drainage to feed. If clean pasture is available, pregnant cows close to calving should be rotated there while cow-calf pairs remain on the current pasture. If calving in a barn or shed, the calving pen should be kept clean and dry with frequent changes of bedding to remove the build-up of organisms. Make every effort to get the cow and newborn calf out of the barn quickly to lessen the chances of infection.
- Don’t bring in a new disease. Purchasing animals, cows or calves, and bringing them home to the farm is likely the single most dangerous time for introduction of new diseases into a herd. Purchasing a calf to put on a cow that lost her calf is an excellent way to start a scours outbreak among newborn calves. Newly purchased animals should not be mixed into a group of calving cows. Any newly purchased animals should be isolated either off the farm or in a well-segregated area for at least 2 weeks (3-4 weeks is better) and observed for any signs of illness. During the period of isolation, a veterinarian should be consulted to appropriately test and vaccinate new arrivals. The best practice is to purchase animals from herds of known health status that will provide a vaccination history. Even show animals returning to the farm from events should be isolated for 2-3 weeks to prevent introduction of disease when they re-enter the herd. Introduction of an animal with a disease such as Johne’s or a BVD persistently infected (PI) animal could have devastating, long-term effects on the health of the cow herd.
There will always be exposure to infectious agents, despite the best farm biosecurity measures. The immune system of cattle is well-designed to intercept infectious agents and neutralize their effects as long as immune cells are functioning correctly and the number of infectious organisms does not become overwhelming in the environment. With newborn calves, survival depends on colostrum intake, but it is also the development of the immune system during gestation or “fetal programming” that plays an important role in overall calf vitality. In short, prevention of disease is far more than vaccine and deworming protocols; it is largely the result of day-to-day management practices instituted on the farm to keep adult cows healthy, well-fed, and clean.