Calves on the ground. When the sale of calves is your primary source of revenue most years, it's important the birthing process goes smoothly. Accordingly, we are always attentive when we have expecting cows or heifers. Ideally, we know which animals are close to birthing so we can keep an eye on them. Usual gestation for cattle is 282 days (approximately 9 1/2 months). We have selected a breed, and cows and bulls within the Angus breed, that usually don't have any problems calving. Other than heifers, we may have to help one cow out of a hundred during our calving seasons.
Our cows usually begin to spring (swelling of the vulva) about a week to ten days prior to delivery. Most cows' utters will also begin to swell, but that is an unreliable predictor of how close she is to birth--especially in heifers. A few hours before delivery, most cows will leave the herd and lay down and get back up several times. During this time, you will begin to see uterine contractions, usually ten to fifteen minutes apart. The water sac may also be expelled during this time--which is a normal process. We usually "start the clock" at the beginning of the next stage--when the calf enters the birth canal.
Typically, you can see feet when the calf enters the canal prior to birth. If we are there when this happens, we give the cows about an hour to deliver the calf naturally. Another sign this stage has started is the timing of the uterine contractions, which begin occurring every two minutes. During this period, it is normal for a cow to lay down and clear the front shoulders and head. It's natural to want to intervene and help, but often allowing the cow to do this step on her own means giving her some space and peace. In most cases, if we see a couple feet and a nose, we'll give the cow an hour to pass the front shoulders of the calf. After this happens, she usually stands up and expels the calf. Within a day of delivery, she has typically passed all afterbirth.
The difficult cases to call are those in which you arrive mid-process and have no idea how long the calf has been in the birth canal. Further, in our experience, there's a problem if you see one or two feet facing up, or you see one hoof and a nose, or if you can tell the hind end of the calf is coming out first. If you attempt to assist the cow yourself, remember it's very easy to cause nerve damage during the process--so be as gentle as you can. Among others, Mississippi State University has a good article on assisting a cow during calving (see below link).
Ruby Cattle Company
East Texas Angus Producers