Manual Rupture Versus Transvaginal Ultrasound-guided Aspiration of Allanto-amniotic Fluid in Multiple Pregnancies: A Clinical Approach to Embryo Reduction in Dairy Cattle

Abstract

Abstract.To avoid the problems associated with twinning in dairy cattle, one of the embryos may be eliminated. This study compares the effect on pregnancy maintenance of two embryo reduction techniques, manual rupture (MR) and transvaginal ultrasound-guided aspiration (TUGA) of allanto-amniotic fluid, in Holstein-Friesian cows with multiple pregnancies. In the first experiment, 61 lactating cows bearing unilateral twins (n=27), bilateral twins (n=30) or triplets/quadruplets (n=4) were subjected to MR (n=45) or TUGA using a 17-G neddle (n=16) on day 28-34 of gestation. In 21 and 10 cows undergoing MR and TUGA embryo reduction, respectively, pregnancy loss occurred before day 90 (46.7 vs. 62.5%, P= 0.28). Through binary logistic regression, the type of pregnancy was identified as the only variable significantly affecting pregnancy maintenance (P=0.03). Based on the odds ratio, the risk of pregnancy loss was 4.1 times higher for unilateral twins than for bilateral twins (70.4 vs. 36.7%, respectively, P=0.01). No effect was detected on pregnancy maintenance of the technique used (P=0.17) or of the interaction technique by type of pregnancy (P=0.22). In the second experiment, a 22-G needle was used to perform TUGA on 22 lactating cows. The pregnancy loss rates were 44.4% (4/9), 18.2% (2/11) and 50% (1/2) for cows bearing unilateral twins, bilateral twins and triplets, respectively. The total pregnancy loss rate following TUGA using the 22-G needle tended to be lower than that using the 17-G needle (31.8 vs. 62.5%; P=0.06). Our results suggest that TUGA using a 22-G needle could be the method of choice to perform embryo reduction in cows carrying multiple pregnancies. M ultiple pregnancies (twins or higher-order pregnancies) are undesirable in dairy herds. Whilst cows carrying triplets and quadruplets are unlikely to maintain their pregnancies to term [1], cows delivering twins are more likely to suffer peripartum diseases and to be culled [2]. Twinning increases not only the risk of pregnancy loss [3,4] but also the risks of dystocia, stillbirth and calf mortality [5][6][7][8]. Over the past 20 years, twinning rates in dairy cattle have increased alongside milk production [2,5,9]. Estimates currently run at 9%, with rates of 0.3% to 12% reported among herds [10], and it is foreseeable that this twinning rate will continue to increase.Transforming a multiple pregnancy into a singleton pregnancy by inducing embryo reduction should in theory avoid the negative effects of multiple pregnancies in dairy cattle. However, the embryo reduction technique itself may carry an additional risk of pregnancy loss. Embryo reduction by manual rupture (MR) of the amniotic vesicle during the late embryonic/early fetal period has been assessed in unilateral [11,12] and bilateral twin pregnancies [12]. In these studies, pregnancy loss rates of 28.6 to 100% were reported. Transvaginal ultrasound-guided aspiration (TUGA) is an alternative method to MR for embryo reduction in twin-pregnant mares [13][14][15], although as far as we know, TUGA...

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

“…The presence of a dead co-twin may be detected at the time of pregnancy diagnosis and its incidence could be as high as 16% [6]. Similar results have been obtained for the methods transvaginal allanto-amniotic fluid aspiration and manual amnion rupture [10,36]. Since the aspiration-based method is ultrasound guided and requires two people, we prefer to induce embryo reduction by manual rupture of the amniotic vesicle of bilateral and some unilateral twin pregnancies within our weekly visit program in controlling reproduction.…”

Luteal activity following follicular drainage of subordinate follicles for twin pregnancy prevention in bi-ovular dairy cows

“…Other proposed approaches to reduce twinning in cows on Days 28-41 of gestation consist of manual rupture of the amniotic vesicle and transvaginal ultrasound-guided aspiration of allanto-amniotic fluid or intra-luteal instillation of PGF2α in one of the two corpora lutea (López-Gatius, 2005;Andreu-Vázquez et al, 2012c;López-Gatius and Hunter, 2016). However, although inducing twin reduction avoids the negative effects of twinning, these interventions may increase the risk of pregnancy loss.…”

Effect of elevating luteinizing hormone action using low doses of human chorionic gonadotropin on double ovulation, follicle dynamics, and circulating follicle-stimulating hormone in lactating dairy cows

“…Although the results of this study did not result in a practical approach to decreasing DOV and twinning in lactating dairy cows, it did provide physiologic information that may focus future studies in this impor-tant area. Future studies may focus on reducing DOV through increasing circulating P4 during preovulatory follicle development using protocols such as Double-Ovsynch (Cunha et al, 2008;Wiltbank et al, 2012;Martins et al, 2018), genetic selection for reduced twinning or DOV (Lett and Kirkpatrick, 2018), aspiration of codominant follicles to increase likelihood of SOV (López-Gatius and Garcia-Ispierto, 2020), or use of embryo reduction (Hanrahan, 1983;Andreu-Vázquez et al, 2012b;. In regard to follicle aspiration, we have recently demonstrated that follicle aspiration can be used to reduce number of DF and ensure ovulation of a single DF in each ovary to increase bilateral twinning rates in beef cattle that are carriers for the high fecundity Trio allele (Madureira et al, 2020).…”