Getting calves off to a good start is vital if we want to have a calf to wean in the fall.
Research shows that 70 percent of calf mortalities occur within the first 96 hours of life.
Almost two-thirds of these losses are directly attributable to dystocia, or calving difficulties.
Too much time spent in the birth canal can kill a calf because of a lack of oxygen.
However, calving problems also cause indirect losses by increasing the susceptibility of surviving calves to infectious disease.
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Calves that have difficult births are often slower to get up and start sucking, which results in poor colostrum intake and lower immunity.
Those that survive dystocia are 2.4 times more likely to become sick during the first 45 days of life. Calving difficulties may be the root cause of many outbreaks of infectious diseases encountered in cow-calf herds.
We’ve made great strides in reducing calving difficulties over the last 20 years, but it continues to be a priority because they are such an important risk factor for calf mortality.
There are steps producers can take to prevent dystocia :
Select bulls for low birth weights
Birth weight is the most important factor contributing to dystocia. It is a function of genetic and environmental factors and is moderately heritable.
Producers should select a bull with a low birth weight or a low expected progeny difference for birth weight when breeding heifers.
Adequate nutrition for replacement heifers
The risk of dystocia is greatest in replacement heifers.
As a result, heifers should reach 85 percent of their mature weight at calving time.
This often means feeding heifers separately from cows during winter.
Heifers have increased nutritional demands because they are still growing and have difficulty competing against mature cows for feed.
Avoid overconditioning heifers so that they don’t lay down excessive fat inside their pelvic canal.
Adequate nutrition for cows
Thin cows often have trouble calving because their energy reserves are low.
Calves from cows in poor condition often don’t perform as well.
Also, mismothering is more common in cows that are thin at calving. Thin cows will be slower to start cycling after calving and less likely to get pregnant.
Aim to have cows calving with a body condition score of 2.5 to three on a five point scale.
Provide assistance when needed
Early assistance in the calving process affects a dam’s subsequent reproductive capacity.
It can also result in a nine percent increase in the number of animals cycling at the onset of the breeding season and a 14 percent increase in the fall pregnancy rate.
As well, early assistance will greatly increase the chance of producing a live calf if an animal does have dystocia.
Good facilities such as maternity pens and a calving squeeze makes a huge difference in producers’ ability to provide assistance.
Heifers tend to take a little longer to give birth than cows. As a result, it is important to understand the normal birth process when providing assistance.
Guidelines on when to provide assistance include:
• if a cow has been straining for 40 minutes and no progress has been made;
• if 90 minutes have elapsed since the first water bag appeared and no progress has been made;
• if the legs emerge with the surface of the hoofs pointing up, which probably means a backward calving;
• if only the head or tail emerges;
• if cow at calving time demonstrates four to five hours of anxiety and walking with the tail extended, which means it should be examined to ensure that a breech presentation has not occurred.
Producers should calve heifers separately two to three weeks before the mature cow herd to allow for concentrated surveillance of the high risk group for dystocias. It also allows heifers to calve in a clean calving area with no pathogen buildup.
As well, it provides a few extra weeks for heifers to recover and start cycling so that they are not behind in subsequent years.
John Campbell is head of Large Animal Clinical Sciences at the University of Saskatchewan’s Western College of Veterinary Medicine.
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