Calving is one of the most stressful events a dairy cow will experience during a production cycle. During this time, the cow must be able to cope with a painful labor along with changes in its environment, regrouping with other cows, and separation from its calf. When cows are unable to cope with these changes, they are at risk for painful conditions such as dystocia (a difficult calving requiring assistance), which may lead to lower milk production and illness after calving.
According to the 2007 USDA National Animal Health Monitoring System (NAHMS), producers reported that 17.2 percent of cows required assistance while giving birth. A difficult calving negatively affects the cow and calf’s health, production, and fertility (see the table). Therefore, it is important to understand normal calving behaviors and the labor process to be able to recognize cows that are experiencing dystocia, to avoid illness after calving, and potentially prevent dystocia.
Signs of normal calving
The cow’s welfare can benefit from farm personnel understanding the normal calving process and behaviors. Labor is described as occurring in three stages.
During Stage I, the cow’s cervix dilates, the uterus begins to contract, and the calf rotates into position for expulsion. This stage is thought to last between four to 24 hours, but can only be confirmed with palpation of the cervix. Indirect physical cues from the cow provide an indication that the cow is in the first stage of labor. These cues include an engorged udder, relaxation of the pelvic ligaments, and discharge from the vulva.
The second stage of labor begins with the breaking of the amniotic sac and abdominal contractions in the cow, as the calf moves into the birth canal. At this stage, it is clear that the cow is in labor because it is actively pushing and the amniotic sac is broken or present outside the vulva. According to researchers at The Ohio State University, after approximately 70 minutes (give or take 40 minutes), this stage ends with expulsion of the calf.
Stage III is characterized as expulsion of the placenta. That is followed by involution of the uterus.
In conjunction with physical changes, a normal calving can also be recognized using behavioral cues. The time at which the cow’s behavior begins to change varies based on the cow’s environment at calving.
Research from the Swedish University of Agricultural Sciences reported that cows housed in an extensive, pasture-based system began to show signs of labor on the day of calving by isolating themselves from the herd. In their study, dairy and beef cows sought out a secluded area that was dry (dried leaves) and had natural forage cover (trees and bushes). This isolation behavior is thought to promote bonding between the cow-calf pair without interference from other cows, and it may be an anti-predator strategy.
Changes in behavior during labor may be less obvious for cows housed indoors at calving. However, some cows that are housed indoors may still try to express the same isolation-seeking behavior. Researchers from University of British Columbia’s Animal Welfare Program found that some cows calving indoors isolated themselves from other cows starting about eight hours before giving birth when a hiding space (shelter) was provided in the maternity pen.
Other behavioral cues during labor may be more subtle, but have been detected in studies housing cows indoors where we can keep close watch. For example, researchers from University of British Columbia’s Animal Welfare Program found that feeding time fell from approximately 200 minutes to 135 minutes on the day of calving.
Researchers from the University of Edinburgh found that the number of times a cow transitioned from standing to lying went from 16 bouts three days before calving to 24 bouts during the six hours leading up to calving. Cows also raised their tail 59 times during the six hours before calving compared to an average of 19 times three days before calving.
Furthermore, researchers at Aarhus University reported cows turned their head to their abdomen 16 times during the final two hours of labor as compared to only two to three times during the two to 12 hours before calving. Farm personnel can use these physical and behavioral indicators to ensure calving is progressing normally.
Using clues to identify dystocia
Additionally, researchers from the University of Edinburgh found that cows requiring assistance became more restless (as indicated by more frequent transitions from standing to lying) two to four hours before calving compared to unassisted cows. Also, cows raised their tail more frequently and for a longer period of time beginning six hours before calving compared to unassisted cows. Being able to recognize these deviations from normal calving behaviors can allow farm personnel to closely monitor cows that are more likely to experience dystocia. This will help personnel intervene and provide assistance at the necessary time.
It is critical that farm staff intervene only when necessary. Cows are motivated to find a quiet place to calve, and labor will stall when they are disturbed. Researchers at The Ohio State University suggest that cows in labor should be checked every 15 to 20 minutes for signs of labor progress (progressing from signs of abdominal contractions to the presence of calf feet, for example). Cameras viewing the maternity pen are an option to allow for frequent viewing without constantly disturbing them.
If progression is not apparent, the position of the calf needs to be assessed along with an estimation of calf size by palpation for feasibility of moving through the birth canal. Ohio State University researchers suggest cows should be assisted 65 minutes after feet are seen if no further progress has been made. It is critical for farm personnel to be properly trained by experienced individuals or a veterinarian in calving assistance for the safety of the cow and calf.
Calving behaviors matter
Calving affects the cow and calf’s health, production, and fertility. The cow is vulnerable to the stress and changes it experiences around the time of calving, which makes it more susceptible to contracting illness after birth. A long and stressful labor also has negative impacts on the health and future potential of calves that survive the process.
Research of calving behaviors has taught us that cows want a secluded quiet place to calve, so less disturbance during this time is ideal. The ability to recognize normal and abnormal calving behaviors can provide great value when monitoring the calving process, as it provides personnel with the ability to determine when assistance is necessary.
