Weak Calf Syndrome
There have been many reports of weak calves born this year from producers and veterinarians. Unfortunately, there is not a simple solution for the weak calf syndrome. There are multiple potential factors that are involved with the weak calf syndrome including nutrition and BVD virus. Additionally, the inciting cause of many cases of weak calf syndrome is not diagnosed. Typically, weak calves are born alive but die shortly after birth. Many of these calves never stand and nurse by themselves. If they do stand they are very slow in getting up and never do well, usually dying within 3 days. With intensive management these calves can be nursed along but some will die no matter how exhaustive the therapy.
One important factor this year is the increased concern about weak calf syndrome is the severe winter seen throughout Iowa this year. Pre-partum nutrition is key for preparing the calf for life outside the uterus. Up to 80% of fetal growth occurs in the last 50 days of gestation. Therefore the dam needs adequate nutrition to support the tremendous required growth in the fetus and supply enough additional nutrition to for the calf to have enough reserve to be able to stand and survive after birth.
Protein is one of the biggest nutritional components necessary for fetal development. Calves born from protein restricted dams have decreased calf vigor, decreased thermal heat production, and increased time from birth to standing. A good rule of thumb is that late gestation cows need 2 lbs of protein per day.
Energy is also important for the fetal calf. Fetal brown fat supplies the energy needed for the calf to survive until adequate colostrum and subsequently milk is ingested. Cows need at least 11 Mcal of energy per day. However, during extreme cold weather this requirement increases. Producers need to adapt and feed their cows to fit the environmental conditions. It is important to recognize that although pregnant cows can be roughed through much of the winter, this practice should not include late gestation. Calves born to cows that were losing weight during late gestation will have lower energy stores and longer interval from birth to calving. Additionally, these cows will take longer to breed back.
BVD virus has also been associated with weak calves. This virus is capable of causing multiple congenital problems depending upon the stage of development that the calf was infected. Calves that have had an in utero BVDV infection have been reported to have hydrocephalous, immature, dummies, or weak in general. If BVDV is suspected contact your veterinarian so that a targeted testing program can be instituted.
Producers should also focus on good management practices during calving. Birth in general is a traumatic event for the calf and dystocia can further exacerbate problems. Dystocia calves will also have decreased calf vigor, weaker and a longer interval from birth until standing. As always a clean dry calving environment helps the calf get off to right start. A calf that is born into a cold wet environment is going to have to spend more energy keeping itself warm before it ever has a chance to stand and nurse.
The biggest problem with weak calf syndrome is that there is little that can be done at this stage. The cold weather is coming to an end and the nutritional program during late gestation has already been instituted and we are now dealing with the ramifications. Additionally, any affect that BVDV had on the fetus occurred months ago. Weak calf syndrome is something that has to be prevented with good animal health and nutritional programs well in advance of the calving the season. If you are experiencing weak calves pay close attention to close up females and minimize dystorcia. Newborn calves should be kept in a clean dry environment. If calves have not stood and nursed within 6 hours the dam should be restrained, milked out and the colostrum fed to the calf.
