In large pasture situations, beef cows tend to leave the herd and seek more isolation shortly before calving. This behavior has several advantages for the cow and her newborn calf. Isolating herself from the herd allows a cow to calve in seclusion, and the mother-offspring bond can be formed without disturbance by other cows.
While the behavior initially seems advantageous, it can prove risky in areas with predators. Casey Anderson, manager of the OX Ranch near Boise, ID, experienced such predation loss firsthand in 2009 when 72 calves and five cows were killed by wolves.
Cows spend most of their time in social groups of several animals, which allows a group defense in chasing away predators. When calving, however, a cow tends to isolate herself, thus increasing her, and her calf’s, exposure to predation.
A Colorado State University study conducted in spring 2011 found that individual cows differ in their vigilance level toward their surroundings after calving (Flörcke et al., 2012). And those differences in vigilance were correlated with the spiral hair whorl (HW) pattern on the cows’ foreheads. Cows with HWs appearing higher on the forehead, as well as cows with multiple HWs, were more vigilant compared to cows with other physical HW traits.
A Closer Look: Study Examines Cow’s Protection Behavior
A follow-up study analyzed individual cows’ separation distance during parturition from the herd and a possible correlation with cow age or HW position. The study also was conducted in Colorado in spring 2011 on a Red Angus beef cow operation.
The cows ranged from 3-6 years of age. Researchers measured the distance of separation from the herd during the calving of 333 animals in a pasture size of 320 hectares (790 acres). To collect data on the separation distance, each cow and her newborn calf were approached within the first 24 hours after parturition and GPS coordinates were recorded for each cow-calf pair.
Data was collected while the main herd would aggregate around the feeding area in the morning; only cows that recently calved or that would calve that day remained separated from the main herd. The separation distance of each cow-calf pair in relation to the main herd at the feeding area was calculated.
The results indicate that the cows preferred sandy soil and cover by bushes for calving. Overall, 88% of cows separated from the main herd by more than 100 meters when calving, and the age of a cow greatly influenced the separation distance for parturition.
The three-year-old cows calved at random places all over the pasture (Figure 1). Meanwhile four-year-old cows actively separated furthest from the herd, which may be a coping mechanism to guarantee undisturbed calving without interference by older cows and to assure a well-developed mother-calf bond. On average, the five- and six-year-old cows calved much closer to the main herd. Researchers concluded that the HW position did not affect the separation distance.
Social dominance hierarchy
The results likely represent the social dominance hierarchy within the cowherd. Five- and six-year-old cows are full grown and thus more dominant than younger cows. These cows can chase away other individuals that approach during calving.
Another Perspective: Survey Shows Producers Tolerate Aggressive Cows
Meanwhile, three-year-old cows are still rather inexperienced and calve in random places. Four-year-old cows retreat furthest from the herd, probably to avoid encounters with older, more dominant cows while calving.
These findings were rather surprising to the rancher. Cows were fed every morning and it was expected that younger cows would stay in close proximity to the herd and the feeding area.
The predicament that arises is that younger cows, which lack experience, subject themselves to increased predation pressure when they calve further away from the main herd. The bottom line is that in areas with predation, ranchers should keep their parturient cows in pastures in close proximity to the barn and monitor them frequently.
Cornelia Flörcke is a Colorado State University graduate research assistant.