Twins in Dairy Herds. Is It Better to Maintain or Reduce a Pregnancy?

Abstract

Multiple ovulations and so multiple pregnancies have increased recently in dairy cattle. The incidence of the double ovulation impact in high producers at insemination may be over 20%. Twin pregnancies are undesirable as they seriously compromise the welfare and productive lifespan of the cow and herd economy. Clinical problems extend from the time of pregnancy diagnosis to pregnancy loss, abortion or parturition. Early pregnancy loss or abortion of multiple pregnancies lead in most cases to culling. In cows reaching their term, mean productive lifespan is up to about 300 days shorter for cows delivering twins than for cows delivering singletons. While there is an urgent need to address multiple pregnancy prevention procedures in the foreseeable future, the incidence of twin pregnancies continues to rise in parallel with increased milk production. Herein, we review two contrasting measures proposed for the time of twin pregnancy diagnosis: (1) gonadotropin-releasing hormone treatment for pregnancy maintenance, or (2) embryo reduction. These options are discussed in terms of their implications for individual animal health and herd economy. Our main conclusions find that manual twin reduction has proven to be the best management option, whereas the use of prostaglandin F2α for inducing abortion may be a better option than doing nothing.

Genomic Prediction for Twin Pregnancies

“…Previously, Fricke (2015) [ 30 ] has proposed a two-pronged approach including (1) using a Double Ovsynch protocol before artificial insemination, and (2) selective reduction of unilateral twins/selective maintenance of cows with bilateral twin pregnancies. Lopez-Gatius (2020) [ 31 ] outlined using gonadotrophin-releasing hormone treatment for pregnancy maintenance and embryo reduction preferentially using PGF2 depending upon multiple factors such as genetic merit and stage of lactation. We propose a hybrid approach in which genetic merit information is utilized to differentially inform management decisions for cows, using a selection index value as the first consideration, followed by the TWIN trait merit, and subsequent management protocols.…”

“…Once diagnosed, current intervention and management practices for twin pregnancies include (1) GnRH treatment to maintain the gestation, (2) induced embryo reduction through aspiration of the allanto-amniotic fluid or manual rupture, (3) induced abortion using PGF 2α , and (4) culling. Limitations of these methods include an increased likelihood of pregnancy loss in the embryo that was not selected for manual reduction, and in the case of pregnancy maintenance, the aforementioned periparturient diseases and abortion, stillbirth, calf mortality, and dystocia [ 11 , 12 , 27 , 30 , 31 ]. Opinions differ on what is the optimal way to manage females carrying twin calves, with some advocating manual embryo reduction [ 27 ], and others suggesting selective culling and selective maintenance of pregnancy, depending on the value of the cow and calf(ves) as the preferred alternative [ 12 ].…”

Thermal Mechanisms Preventing or Favoring Multiple Ovulations in Dairy Cattle

“…However, the most immediate question that needs addressing is how to reduce the risk of twin pregnancies and twinning. To this end, the transfer of a single embryo or drainage without suction of co-dominant follicles are recently proposed strategies [59,60], whereas once a cow becomes pregnant, management of twin pregnancies has also been discussed [61]. The follow-up of multiple ovulations following insemination is mandatory for optimizing reproductive management in dairy cattle.…”

Twin Pregnancies in Dairy Cattle: Observations in a Large Herd of Holstein-Friesian Dairy Cows

“…This figure most likely exceeds the breakeven point to maintain this type of pregnancy in a dairy herd. Interest (or absence of interest) of twin reduction has been discussed in a recent commentary [ 42 ]. To improve herd economy, induced twin reduction is the best management option and the use of a luteolytic agent to induce abortion upon a diagnosis of twins that may be a further suitable option [ 6 ], but, more effectively, would be to prevent twin pregnancies via transfer of a single embryo or drainage of subordinate follicles at insemination [ 43 , 44 ].…”