The loss of a calf is only the beginning of the negative impacts of stillbirths, Michael O’Connor noted in Penn State’s Dairy Digest. Longer-term consequences include increased incidence of postpartum disorders, including prolapsed uterus, uterine infection and displaced abomasum. These events result in prolonged days to conception and increased cull rate.
Cows that had stillbirths were 41% more likely to be culled, according to 2007 Cornell University research, which studied 13,608 calvings on seven dairy herds. The research also found cows with stillbirths had a 24% lower rate of becoming pregnant, and a difference in mean days open of +26 days compared to cows giving birth to live calves.
If there was just an occasional stillbirth, the problem might not cause such concern. But a 2000 Iowa State study including data from 666,341 births on U.S. farms found 7% of Holstein calves die within 48 hours of birth, O’Connor wrote.
The Cornell and Iowa State research identified parity and calving ease as major risk factors for stillbirths. In the Cornell study, the incidence of stillbirths on seven dairies was 6.6%, ranging from 4.1% to 10%. Stillbirths among first-parity cows was 10.7%, compared to 3.6%, 5% and 4.2% for second, third and fourth parities, respectively.
The rate of stillbirths by calving ease ranged from 3.6% to 60.1% in the Cornell study. The odds of stillbirths were 88% lower for unassisted calvings compared to assisted calvings.
“Since calving ease score is significantly related to stillbirth, any management intervention to reduce the incidence of difficult births should reduce the incidence of stillbirth,” O’Connor said. Use sire and daughter calving ease information when selecting sires to breed heifers to reduce the risk of dystocia.
Other tips include:
• Review calving procedures to ensure proper timing and calving assistance techniques are used.
• Post standard operating procedures for calving.
• Evaluate feeding management so heifers and cows are in the best condition possible at calving.
• Provide enough space and clean, dry bedding to minimizes stress.