It is important for dairy cows to have a live calf every year. Ohio State University has uncovered one method of helping that happen.

In the publication, The Bovine Veterinarian, Maureen Hanson, Ph.D., states that “dry” cows allowed to lie down and rest prior to calving are more likely to give birth to a live calf than those that do not rest. The dry period refers to the three weeks before calving and the three weeks after calving when dairy cows are not milked.

Ohio State University published results of an evaluation of resting dairy cows from three Ohio dairies in The Journal of Dairy Science. In the evaluation, electronic data keepers were used to measure and record the lying-down time and frequency of over 1,000 cows, beginning 14 days before the expected calving date.

The regularity of the cows’ resting sessions was monitored daily, which was called the coefficient of variation. Researchers performed blood analysis one and two weeks prior to calving, testing for non-esterified fatty acid concentration, (NEFA), which involves molecules from triglycerides that provide portions of body fat and energy. NEFA values were evaluated again 48 hours after calving to measure total blood calcium. Higher serum NEFA concentrations prior to calving have been related to higher levels of some diseases found in dry cows.

The study included heifers giving birth to their first calf as well as older cows. Stillbirths, defined as calves that were born dead or died within 24 hours of birth, were also included.  

Stillbirths made up almost 5% of the calves’ studied. Cows that gave birth to live calves had more lying-down time in the seven days leading up to calving than those with stillbirths. Heifers and cows that delivered live calves rested almost one hour longer daily than those that had stillbirths. Older cows with stillbirths had higher concentrations of NEFA prior to calving compared to cows with a live calf, although this was not the case with first-calf heifers.

Improving the factors that allow cows to lie down and rest prior to calving could result in more live births in dairy cows.