The process of parturition in a beef cow involves 3 phases. Phase one is labour, the process of progressive contractions of the uterus. This causes the dilation of the cervix. Phase two is delivery. The event where the calf is expelled from the cow's uterus into the world. Phase three, the often forgotten stage, is the expulsion of the placenta. Stage three can often be forgotten as the likelihood of complications is low with good management and nutrition. However, the retention of this placenta can cause major health problems for the cow. The symptoms can range from bad odour to uterine infections leading to toxins in the bloodstream causing illness and death.
Retrained placenta (RP) can present differently depending on the situation. The most common presentation involves discoloured membranes hanging from the vulva. However, in some cases, the membranes may not appear outside of the vagina. These cases are more difficult to detect and will be indicated by foul-smelling discharge and abnormal cattle behaviours, such as being off-feed. The placenta is considered retained if it has not been expelled 6 to 12 hours after giving birth. If the cow is behaving normally, mothering her calf, and remaining on feed and water, most veterinarians recommend monitoring that cow instead of intervening. However, as soon as symptoms of an illness appear, consult a veterinarian. There is some controversy If the placenta is not expelled in 3 to 4 days after giving birth, interference is recommended. Giving an injectable antibiotic at this 3 or 4 day mark can help to prevent/fight infection. It is suggested to never manually remove the placenta, this increases the risk of causing secondary, severe infections, damaging the endometrium (uterine lining), and reducing white blood cell function.
There are some management factors that can increase the risk of retained placenta. Poor mineral program management can result in cattle with vitamin and mineral deficiencies, which will increase the risk of RP. Trace minerals deficiencies of selenium, copper, cobalt, and zinc have been linked to the increased risk. Vitamin A, D, and E requirements need to be fulfilled prior to, during, and following calving to ensure all three stages of parturition proceed without complication.
There are factors in the delivery phase that factor into the cow's ability to clean (expel the placenta). Dystocia, or calving complications, can increase the risk of RP. Other risk factors include giving birth to a dead calf, having a cesarian section, and artificial induction of parturition. All these processes are related to the initiation of a hormonal cascade involved in giving birth and expelling the placenta. Twins can also increase the risk of retained placenta.
RP affects the production of the cow, which in turn reduces calf performance. If the cow is sick or off-feed, her milk production will decrease. The cow's fertility may also be affected if the infection becomes more severe or spreads to other organs. Therefore, it is in the rancher's best interest to ensure a good mineral program, selection of low birth weight bulls, and reduced interference in the induction of labour.
Getting your feed tested is an important step in understanding your herd's mineral program. Taking liver biopsies is another great way to test mineral and vitamin levels in cattle. Especially if you have a cow die for other reasons, it is a good practice to get the vet out to perform a post-mortem and take liver samples. This will help determine where the rest of the herd stands on their requirements and if you need to adjust your supplement. Please contact me if you have any questions about mineral requirements or any of our products!
Canadian Cattlemen: The Beef Magazine; March 2023