Difficult calf birth: the Causes and how can it be avoided

Dear Daktari, I am Josephat Karanja from Naivasha. My cow recently had a difficult birth and I was forced to call a veterinary doctor to assist with the process. It was successful but it left me with more questions than answers. Did I do anything wrong in terms of nutrition, animal health, or negligence? Could you write about what causes this and how it can be prevented or reduced? Thanks, [Josephat Karanja - Karagita, Nakuru County]

Dystocia is the term used for a difficult birth that requires assistance for the delivery of the calf. Dystocia is one of the factors affecting the survival of a calf. It can result in injuries to the dam or the calf, weakness or death of the calf, and reduced subsequent reproductive performance. Therefore, it is important to try as much as possible to reduce the chances of dystocia.

What Causes Dystocia?

Maternal/Fetal Disproportion is the main cause of dystocia. This simply refers to a mismatch between the size of the fetus and the size of the dam. In this case, the calf is larger than the birth canal of the cow, making it difficult for the calf to pass through during birth, thus causing dystocia. There are many causes of this, and some of them, along with preventive measures, are discussed below.

Higher Calf Birth Weight

Maternal and fetal disproportions often result from calves with relatively higher birth weights, which might be attributed to dietary intake, breed differences between the dam and the sire, or genetic traits of the parents. To address this, farmers should pay special attention to breed selection during breeding to avoid cases of maternal/fetal disproportions. Some animals have relatively smaller pelvic diameters, and such heifers should be culled before reaching breeding age to reduce the incidence of dystocia.

Prolonged Gestation

Sometimes cows tend to go past the estimated date of delivery by a few days. This presents a difficult birth risk as the birth weight increases by 135 to 370 grams per day. Gestation length is a genetic trait, and some animals have shorter or longer gestation periods. The sex of the calf is another factor that can determine whether a cow will experience a difficult birth. Normally, bull calves have higher weights, partly because most dams carrying bull calves tend to have prolonged gestations, leading to an increase in weight. The likelihood of dystocia in dams carrying male calves is twice that of those carrying female calves.

Age and Parity of the Dam

Parity refers to the number of times a dam has previously given birth. The incidence of difficult births decreases as the dam’s parity and age increase. First-time calvers experience the highest rate of dystocia because the birth canal is relatively smaller. In adults, the lower incidence of dystocia can be explained by the fact that as the cow matures, so does its body size and pelvic area compared to heifers. Adult cows can develop and give birth to heavier calves due to their larger birth canals.

Breed of the Dam or Sire

Larger breeds of cattle, like Friesians, have larger pelvic areas and can produce calves with heavier birth weights than smaller breeds. Smaller cows, like Jerseys, when mated with larger breeds like Friesians, can easily be predisposed to dystocia due to maternal/fetal disproportion. This can be controlled at mating through proper selection.

[Dr. Othieno is a veterinary surgeon and currently the head of communications at the Food and Agriculture Organization of the United Nations Kenya. The views expressed here are not necessarily those of FAO but his own]