Every dairy producer’s goal is to have uncomplicated calving. But their practices aren’t always conducive to reducing dystocia risk. Eutocia, or normal birth, requires prevention and preparation and is dependent upon many factors.
Reducing incidents of dystocia in the dairy herd is a long-term goal.
Dr. Harry Momont, University of Wisconsin – Madison, presented a workshop on calving assistance at the 2016 Cornell Calf and Heifer Congress. In a follow-up interview, he further addressed these practices, and the best measures – both short-term and in the long run – to take to decrease dystocia.
Knowing whether or not a birth is progressing normally, as well as when and how to intervene, means recognizing signs of maternal and calf distress. Knowing when to call in the professionals to prevent further trauma is an important part of dystocia management.
“When it comes to calving, there are a couple of issues that I see over and over again,” Momont said. “The first applies mostly to heifers and that is pulling too hard, too soon. It’s often tempting to help her along, but heifers require a little more time to dilate the caudal portion of the birth canal and pulling too soon can injure both the heifer and her calf.
We need to understand that calving stress, trauma and subsequent pain are significant problems for the transition cow and heifer and do everything we can to avoid them.”
During the first stage of labor, uterine contractions and cervical dilation are occurring. The calf should be in position for birth. The heifer will be off feed, leak milk, have the tail up and appear restless.
If delivery is delayed, something is wrong. Delayed delivery is defined by a first stage of labor lasting longer than six hours or a second stage lasting more than three. Lack of progress after 30 to 60 minutes in the second stage can also indicate an issue.
Signs of a difficult birth include excessive straining, hemorrhage or abnormal odor or appearance of the membranes. If there are not two feet showing, or if there are two feet but no head, the birth is not normal.
The second stage of labor involves active uterine efforts to move the calf into the birth canal, and the rupture of the allantochorion (water bag). This will last for up to four hours in heifers, but it is much quicker – often 30 minutes or up to one hour – in multiparous cows.
If second stage labor is not progressing normally, forced extraction is the goal. Sanitation – using warm water and disinfectant soap, and wearing sleeves – is important. A water-based methyl cellulose or powder lubricant should be used.
The number and position of calves should be determined prior to taking action. Two people should be available for proper pulling.
“I like two long chains and two handles,” Momont said. “They don’t break and they’re easy to clean and sanitize between calvings. A detorsion rod is useful if you are unable to manually correct a uterine torsion.”
While many dairy farms have a mechanical calf-puller (fetal extractor), Momont warns against their use except by trained personnel, due to the excessive force applied to the calf and the dam.
“The other issue I see is the tendency to continue working at correcting a dystocia or pulling a calf even if we are not making any progress,” Momont said. “If you aren’t making significant progress, if there is no light at the end of the tunnel after 30 minutes, call for professional assistance.”
After repulsion, dystocia calves are assumed to need help, Momont said. Normal calves will be upright within a few minutes, will stand within an hour and be actively sucking within two hours. Dystocia calves may require assistance keeping a normal body temperature of 100 to 102ºF, may need to be propped upright and may need resuscitation.
Pouring ice water over the head, a straw in the nose and briskly rubbing the calf while it is in a sitting position can all stimulate respiration.
There are practices that can help to decrease the prevalence of dystocia. A sound nutrition program, combined with the proper age at first calving, is a good place to start.
“Excessive body condition results in fat deposition in the birth canal and can increase the effort and time needed to deliver a calf. This can lead to stillbirths and injuries to the birth canal,” Momont said. “A body condition score of 3.25 to 3.75 is my preference.”
Monitor feed program results via withers and hip height, heart girth and calf weight.
Waiting too long to breed heifers is another common practice that increases dystocia risk. Momont recommends targeting the age at first freshening at 22 to 24 months.
“As heifers age, they tend to gain more fat than lean, increasing the risk for excessive body conditions to interfere with normal delivery,” Momont said. “Reducing the age at first calving puts more stress on the feeding program to assure heifers have adequate pelvic size but are not too fat.
Measuring height at the hips or withers allows us to assess growth more completely, making sure heifers are not just getting fat but are growing as we desire them to.”
Added gestational time also results in much larger calves, which increase the risk of birthing difficulties. Using sexed semen can reduce this risk.
“The impact of longer gestation on dystocia begins with the fact that bull calves are at increased risk for dystocia and are carried one to three days longer than heifer calves,” he said. “Dystocia and stillbirths are more common when gestation length is significantly longer or shorter than normal.
The line between short gestation and late-term abortion is a blurry one, and similar disease processes are involved in both.”
Daughter Calving Ease (DCE) measures the ability of a heifer to deliver a calf easily and her tendency to produce a calf born with a calving ease score of 1, 2 or 3 on a 5-point scale. DCE measures the impact of the heifer’s sire, not the sire of the calf.
This measure, rather than Service Sire Calving Ease (SSCE), provides a better measure to improve dystocia in the herd. Using calving ease sires and sexed semen can provide short-term benefits to the herd.
“In the long term, the dairy industry should consider placing more emphasis on DCE as a selection criteria when developing genetic indexes,” Momont said. “Keep in mind that SSCE selection provides a one-time benefit to the heifer. When selecting for DCE, each resulting heifer will benefit every time she has a calf for as long as she lives.”
Tamara Scully, a freelance writer based in northwestern New Jersey, specializes in agricultural and food system topics.