In 2001, Paul Fricke, Ph.D., of the University of Madison-Wisconsin wondered if it were possible to put together a list of management strategies to mitigate twinning in lactating dairy cows.
Looking into the topic, he realized there was a significant lack of literature on how to manage and/or prevent twinning and then set out to change that.
Recently, at the 2016 Dairy Cattle Reproduction Council (DCRC) annual meeting in Columbus, Ohio, Dr. Fricke addressed a crowd of over 200 dairy producers and veterinarians at a breakfast sponsored by Merial, the meeting’s platinum sponsor, with a presentation on the management of twinning in lactating dairy cows. Below is summary of his presentation. *
Dr. Fricke began with a look back at twinning across time in the Holstein population with one of the largest data sets ever examined on twinning, consisting of almost 2.3 million calving events. He saw the yearly reported rate of twinning was increasing, rising to over 7% in older lactating cows.1
While twinning may mean an extra calf born, it’s not exactly a “two for the price of one” deal. Twinning can have negative impacts on cows, including an increased average days open after calving and higher risks for abortion and dystocia. Due to higher calf mortality rates and instances of birth abnormalities, twinning decreases the number of replacement heifers, according to Fricke.
While Dr. Fricke has been studying the hormonal changes responsible for twinning, he also has looked at what level of milk production cows are most likely to twin. Cows with high milk yields near the time of ovulation have double ovulation rates three times greater than cows with lower production.1 As the dairy industry has selected genetics in Holsteins for high milk production, it has also seemingly selected for twinning. The primary mechanism responsible for the increased twinning over time in lactating cows is double ovulation resulting from decreased progesterone concentrations.1 High-producing cows, according to a hypothesis proposed by Dr. Milo Wiltbank at the University of Wisconsin-Madison, have a high feed intake, which helps them produce more milk but also creates a higher rate of blood flow to the liver and a higher metabolism of progesterone that can lead to twinning.1
Farmers and their veterinarians can help mitigate twinning in their high-producing cows by being vigilant in observing cows. Helping to identify those cows with high risks will help lessen the loss of fetuses and place less stress on the cow. Fetal loss is three times higher in unilateral twin pregnancies, where both fetuses are forming either in the left or right uterine horn, than bilateral twin pregnancies.1
Dr. Fricke discussed the popular notion that reproductive protocols get blamed for higher twinning rates, when in fact data from several studies supports the opposite. According to Dr. Fricke, fertility programs such as Double-Ovsynch can help reduce double ovulations in high-producing dairy cows by increasing progesterone during the follicle selection process.
Dr. Fricke’s advice to veterinarians and producers was to properly administer a Double-Ovsynch program while closely monitoring high-producing cows for proper hormonal manipulation to decrease twinning. He encouraged producers to work closely with their veterinarians for a Double-Ovsynch protocol where appropriate.
Source – Dairy Herd