Understanding the Calving Process for Timely Intervention
Whether you are a dairy producer or a beef producer, raise your animals on pasture or in confinement, or prefer crossbreds to purebreds, at the end of the day, a bovine is a bovine. Regardless of your goals or operation size, calving is a universal process and its physiology is essentially the same for all bovines. Understanding the physiology of calving can help you better understand when and if intervention is necessary to ensure the health and wellbeing of your cows and calves.
Stages of Calving
The calving process is broken down into three stages and the end of each stage is marked by a significant event.
Stage 1: Dilation of the Cervix. This is the longest stage of the calving processes and generally lasts anywhere from 2 to 12 hours. Cows often progress through stage 1 faster than first-calf heifers. During this stage, the cervix dilates and softens and the pelvic ligaments relax, which will allow for the calf and fetal membranes (afterbirth) to pass during the later stages of calving. Uterine contractions also begin to occur in this stage and push the amniotic sac and calf against the cervix. Signs of stage 1 are very subtle and difficult to detect but include: decreased feed intake, decreased rumination activity, lifted tail, increased restlessness, and increased efforts to seek isolation. Stage 1 is complete when the cervix is fully dilated and the calf begins to pass into the birth canal.
Stage 2: Delivery of the Calf. This stage of calving is the most obvious because progress can be observed more visually than in stage 1. Stage 2 begins when the calf passes through the birth canal and the amniotic sac (i.e., water bag) becomes apparent at the vulva. This stage typically lasts anywhere from 1 to 2 hours for cows and 2 to 4 hours for heifers. Stage 2 is complete when the calf is completely delivered.
Stage 3: Delivery of the Placenta. This is the final stage of calving where the placenta is expelled. Normally, this process takes less than 24 hours. After the placenta is passed, stage 3 is complete.
Determining when and if Intervention is needed
At some point or other, it is likely that you will need to assist with a calving. Proper timing of intervention is critical to the health and wellbeing of the cow and the calf. Intervene too early and you risk causing undue stress or injury to the cow; intervene too late and the pair may sustain devastating injury or even death. So when should you intervene? The answer is that it depends on several factors, including the stage of calving.
During stage 1, cows and heifers should be checked frequently (approximately every 2 hours) for signs of progress. It can be helpful to set an alarm on your phone to remind you to check the cow regularly. If progression from stage 1 to stage 2 is not made within 4 to 8 hours of the onset of stage 1, conducting a vaginal exam can help determine if there is a problem. Determining when to intervene at this stage can sometimes be a difficult call since the exact time when stage 1 began can be a bit obscure. Activity monitors or calving sensors can be extremely useful in helping you determine the onset of stage 1, and thus, when intervention may be needed. Problems that may prolong stage 1 include improper calf presentation, inadequate cervical dilation, and uterine torsion (twisted uterus).
During stage 2, there are several instances when intervention may be necessary. If the amniotic sac or feet are visible for more than 65 minutes without any apparent progression, the cow has been straining for more than a half hour without progress, the cow stops trying for more than 20 minutes after a period of progress, or if you think the calf is not positioned properly (e.g., only one leg is coming out, the back legs are coming first, the tail is coming first, etc.), then you should intervene. Signs of calf distress also indicate a need for assistance. A calf in distress may have a swollen nose or tongue and may be stained yellow from passing meconium (i.e., the first manure) in utero. In this case, the calf should be delivered as quickly as possible and additional measures may be needed to revive the calf after delivery.
After the calf is delivered, the cow should complete stage 3 within 24 hours. Failure to pass all of the placental membranes within 24 hours after the calf is born results in what is referred to as a “retained placenta,” a condition that can sometimes lead to infection and subsequent fertility issues. Cows that experience a difficult calving or deliver multiples are more likely to develop a retained placenta. The retained membranes should never be manually removed from the cow because this can worsen the problem or damage the reproductive tract. If the cow has a retained placenta and appears ill, she will likely require antibiotics so it is important to communicate with your veterinarian to determine the course of treatment if this situation arises.
Use a Vaginal Exam to Inform Intervention Strategies
Not only is a vaginal exam recommended to help determine if and when intervention is needed during stages 1 and 2, but it can also help you decide the type of intervention that may be necessary. Observations made during the vaginal exam can also make communicating with your veterinarian much easier in the event that you call them for advice or assistance. The goal of the vaginal exam is to determine 1) the extent of cervical dilation; 2) the presentation of the calf; and 3) if the calf is alive. You should discuss with your veterinarian how to properly conduct a vaginal exam. Proper technique and sanitation is necessary to avoid injury to the cow and calf and prevent the introduction of harmful pathogens into the reproductive tract that can cause infection.
Don’t Be Afraid to Call for Help
Being proactive and having a good relationship with your veterinarian is a must for anyone who will be calving in cows or heifers. It is important to know how to reach your veterinarian after hours should you determine that you need help assisting with the delivery of a calf. If you do decide to intervene during calving and you have tried to correct an issue for more than 30 minutes without making progress, or if you don’t know what the problem is or how to fix it, ask for help. No one has all the answers and there is no shame in admitting that you need help. Doing everything in your power to ensure the health and wellbeing of the cow and calf includes your ability to acknowledge when you are in over your head.
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