Weak Calf Syndrome
Weak Calf Syndrome (WCS) is a herd problem that typically describes calves that are born alive, but lack normal vigor. Many of these calves die shortly after birth. Often, affected calves cannot stand and nurse by themselves. There are multiple factors that may contribute to WCS during gestation including suboptimal dam nutrition, mineral deficiencies, and infectious diseases. Ultimately, optimal dam nutrition is the best management intervention to prevent WCS. Prepartum nutrition is essential for preparing the calf for life outside the uterus. Up to 80% of fetal growth occurs in the last 60 days of gestation.
Maternal nutritional deficiencies related to WCS may include lack of energy, protein, and vitamins and minerals. Additionally, severe cold will increase cow maintenance requirements as they burn calories to keep warm, and this should be accounted for when considering nutrition. A good rule of thumb is to manage the feeding program so that cows are at a Body Condition Score (BCS) of 5 (6 for heifers) prior to calving. Heifers are more prone to producing weak calves and their BCS and nutrition program should be carefully monitored and adjusted if needed.
Protein is a critical nutritional component necessary for proper fetal development. Calves born from protein restricted dams have decreased calf vigor, decreased thermal heat production, and increased time from birth to standing. Late gestation cows need 2 lbs. of protein per day.
Energy is also important for the fetal calf. Normally, cows need at least 11 Mcal of energy per day. However, producers should increase energy intake during extreme cold weather. Calves born to cows that were losing weight during late gestation will have lower energy stores and longer interval from birth to standing.
Selenium and iodine deficiency may also be associated with WCS. Supplemental sources of selenium may be necessary in areas where selenium is deficient; however, excessive selenium can be toxic. Other minerals may also be involved so regularly evaluating your mineral program is essential.
Vitamin A and E deficiency has also been associated with weak and stillborn calves. Harvested forages have decreased levels of vitamin A and E compared to green, standing forage. Furthermore, in comparison to high quality harvested forage, low quality forages such as mature or rained-on hay, as well as hay made during drought, and cornstalks have inadequate concentrations of vitamin A and E. Therefore supplemental vitamin A and E are likely needed during the winter months in area where these forages are utilized.
Infectious causes of WCS include Bovine Viral Diarrhea Virus (BVDV) and leptospirosis. BVDV is capable of causing multiple congenital problems in calves. Stillborn calves that are found dead without evidence of dystocia should be investigated by you and your veterinarian. If any of these organisms are suspected, contact your veterinarian to ensure that the correct diagnostic samples are submitted and the test results are used to re-evaluate your herd health program.
Dystocia and Weak Calf Syndrome
Producers should also focus on good management practices during calving. Dystocia calves will usually have decreased calf vigor, appear weaker at birth, and take longer to stand and nurse. Additionally, excessive hypoxia (low blood oxygen) during the birthing process can cause temporary or permanent injury to the central nervous system that may prevent normal activity such as standing or nursing. Histological examination of weak calves indicated that 46% of weak calves had evidence of dystocia and/or hypoxia. Therefore, dystocia may be the biggest factor associated with weak calves, especially when nutrition is adequate.
More information on Weak Calf Syndrome
Center for Food Security/Public Health