“Two for the price of one” is a common marketing scheme to tempt consumers to buy a product. After all, who wouldn’t want twice the value at half the cost? Unfortunately, in the case of dairy cow twinning, it’s a very bad deal. Cows were not designed by nature to routinely carry, deliver and raise two calves simultaneously. While it can and does happen with frequency, twinning in dairy cows is not a desired outcome of a successful breeding program.

Cows carrying twins tend to calve with insufficient body condition, retain their placenta, experience dystocia and take longer to breed back.

“Fortune favors the prepared” is a common adage that suggests that having knowledge beforehand tends to encourage positive outcomes. Helping cows to successfully transition through a twin pregnancy begins with an accurate diagnosis.

If you’d like to get two veterinarians in a heated discussion, ask them if the diagnosis of twin pregnancies is important. It is generally accepted that twinning in dairy cows is bad news. Twins comprise up to 15 percent of freshenings on the average dairy.

As I’ve just stated, there is ample evidence that carrying and delivering twins commonly results in negative health issues such as retained placenta, ketosis and left displaced abomasum (lda). Historically, twin (or triplet or more) pregnancies have been diagnosed by rectal palpation and, with greater frequency lately, ultrasound.

While neither of these diagnostic methods detects all of the multiple fetuses, the majority can be picked up by a skilled palpator or ultrasonographer. More recently, laboratory tests have been developed and commercially promoted that diagnose pregnancy based on the detection of PAG (pregnancy associated glycoprotein) in blood or milk.

While these tests claim to be accurate as well as labor-saving and time-saving, in my opinion they have one major deficiency: They do not detect the presence of twins and triplets. The debate is: Does this matter economically and from an animal welfare standpoint?

I would argue that it matters very much, both to the cow and ultimately to the dairyman’s bottom line. Why is the diagnosis of multiple fetuses, most commonly twins, important? One of the most important values of knowing that a cow is carrying twins is the ability to assist her at calving.

Dystocia, or difficult birthing, is often due to twins being presented at the birth canal simultaneously. Often, one calf will be in a posterior or breech presentation.

Unless every fresh cow is checked for a twin in the maternity facility, the cow may present as a dystocia later, or not at all. If the second calf is missed and not delivered, the resulting mummified fetus can be difficult or impossible to remove.

The result is a once-promising cow relegated to DNB (do not breed) status and milked off. If the remaining, dead twin becomes infected, the cow’s health and reproduction may suffer as well. Knowing beforehand to check for a twin is extremely valuable information that will allow critical intervention at calving.

Cows with twins are more likely to abort. Twins can be present in each uterine horn (bicornual) or the same horn (unicornual). Both presentations can result in a higher than average abortion rate, unicornual twins especially so.

Consequently, it is doubly important that any cow known to be carrying multiple fetuses be rechecked after initial pregnancy diagnosis to ensure that she has not had an unobserved abortion.

During herd health exams, I often note that twins are produced at different rates through the year. The plane of nutrition that the cow is on, especially changes in energy status, are believed to play a role in producing multiple ovulations at estrus. If twins are being produced erratically in your herd, I’d recommend having your advisory team look at ration issues. A sudden increase in twins can be a bellwether for feed delivery or nutrient content issues.

Twins take a physiological toll on the dam. Often she will have difficulty regaining body condition during late lactation and maintaining body condition during the dry period.

While scientific data supporting giving cows carrying twins extra care are conflicting, it may make sense at your dairy to consider either drying cows with twins off early (they tend to calve two weeks earlier than expected, on average) or putting the cow directly into the close-up group instead of a far-off dry pen. Consult with your nutritionist on the feasibility of placing cows in the close-up group for extended periods, especially if anionic salts are being fed to prevent milk fever.

It is common practice to “pinch-off” or eliminate one of the twin fetuses in horses, another species designed to carry only one fetus, early in gestation. This can result in the birth of a normal foal with minimal risk to the dam.

Unfortunately, cattle possess a different type of placental attachment than horses. Attempting to eliminate one fetus may also result in the abortion of both.

Also, unless good records are kept of the procedure, in the situation of mixed sexes, it may result in the birth of a single heifer that is actually an infertile freemartin. While it will be diagnosed eventually as the heifer ages and does not demonstrate estrus, mixed twins noticed at birth can be checked much earlier, thus saving money on feed and housing.

Dairymen place a lot of faith in bull proofs. To assure this confidence, information acquired about daughters must be accurate.

Collection of daughter information begins with the birth and accurate identification of the heifer calf. This process can become confused with the simultaneous birth of multiple calves. The maternity pen or barn on a large, modern dairy can be a busy place.

On a typical 2,000-cow dairy, for example, an average of five cows will calve in a day. In reality, there may be days with no calvings and others with 10 or more. The days with a flush of fresh cows can make properly assigning the correct calves to dams a challenge. The unobserved birth of unexpected twins can cause confusion and incorrect data entry.

If a sire is incorrectly assigned to a heifer calf, her production and other traits will make a bull’s reliability information inaccurate.

For me, the allure of dairy practice lies in the differences among my clients. As in skinning cats, there is more than one way to produce milk.

Whatever method you choose to use for pregnancy diagnosis, I ask that you consider the pros and cons associated with it. I feel that using a pregnancy diagnosis methodology that detects twins, and thereby allows the dairyman to take positive action, is of value to the cow, and ultimately to the farm operation. PD

Paul Biagiotti is a veterinarian with Basin Bovine Practice in Jerome, Idaho. Click here to email him.