Pregnancy and stillbirth losses in dairy cows with singleton and twin pregnancies

Abstract

The aim of this study was to examine the effect of twin pregnancy, fetal laterality, the number of corpora lutea (CL) and cavitary CL on pregnancy losses in Holstein-Friesian cows with a positive pregnancy diagnosis based on ultrasonography between days 29–42 after AI. Pregnancy was confirmed by transrectal palpation between days 57–70 after AI and at the time of drying-off as well. Twin pregnancy rate was 8.4% at the time of the early pregnancy examination. Pregnancy loss did not differ between singleton- and twin-carrying animals either between days 57–70 of gestation or at drying-off. More losses occurred in singletons between days 29–42 and 57–70 in cows with cavitary than in cows with noncavitary CL (12.1% vs. 3.6%; P < 0.05) and in cows with double CL than in cows with single CL (7.3% vs. 3.6% %; P < 0.05). Between days 57–70 of gestation and drying-off this difference was still significant (20.7% vs. 3.7%; P < 0.001), while it was non-significant between cows with one CL (5.7%) vs. double CL (3.7%). Cavity occurrence was not affected by hormone therapy prior to AI (either PGF2α or OvSynch; 4.4% vs. 5.4%, respectively); however, the number of CL was reduced by the treatments (11.6 vs. 19.6%; P < 0.0005). In twin pregnancies there was no difference in the pregnancy losses between bilateral and unilateral pregnancies at any time point. The length of gestation was 278.2 ± 10.5 (singleton) and 267.4 ± 31.2 (twin) days, respectively (P < 0.01). The stillbirth ratio was higher in twin carriers than in singleton carriers (19.5% vs. 5.3%; P < 0.001).

Factors Affecting Pregnancy Rate Per Embryo Transfer of In Vivo Produced Embryos in Recipient Holstein Heifers

“…On the other hand, Alkan et al, (2020) reported that cavity-containing corpora lutea resulted in higher pregnancy rates in heifers receiving fresh in vivo produced embryos. In addition, that, Szelenyi et al, (2019) found that pregnancy losses in Holstein-Friesian cows examined by ultrasonography between days 29-42 after insemination were higher among cows with cavity-containing corpora lutea The present investigation cleared that PR/ET was significantly higher in embryo recipient Holstein heifers in which estrus or heat was induced using PGF2 alpha, as compared to recipient heifers with spontaneous heat. In accordance with our results, in his review, Hasler (2014), documented that PR/ET was higher in recipient heifers with induced estrus after PGF2 alpha, as compared to those with natural estrus.…”

Ultrasound Characteristics of the Cavitary Corpus Luteum after Oestrus Synchronization in Heifers in Relation to the Results of Embryo Transfer

“…Until now, the prevailing view [3] was that in the case of ET, no differences were found in the effectiveness of both morphological types of the CL in recipients. Additionally, more recent studies of the cavitary CL [25] did not suggest a significant relationship between the morphological form of the CL and the pregnancy rate or indicated that the cavitary CL may have a negative impact on the pregnancy rate [32]. It should also be noted that the slightly lower overall pregnancy rate (39%) compared to that reported by other authors [3] could have been caused by a relatively late pregnancy examination.…”

Noninfectious Causes of Pregnancy Loss at the Late Embryonic/Early Fetal Stage in Dairy Cattle

“…An initial diagnosis of a twin pregnancy indicates an increased risk of pregnancy loss [4]. An incidence of twinning among all pregnancies in dairy animals as high as 20% has been reported [5].…”

“…In around 10% of all pregnancies, cows carrying singletons show an additional corpus luteum [27]. At the time of pregnancy diagnosis, 99% of singleton pregnant animals have one corpus luteum ipsilateral to the gravid uterine horn [4]. However, the transuterine migration of embryos has been confirmed and low numbers of contralateral corpora lutea detected in singleton pregnancies can be explained by migration of the oocyte [37].…”

“…Hereafter, the general rate of losses under clinical circumstances ranges from 5% to 20% until day 60 of pregnancy [3], and thereafter, losses range from 1% to 5% [3]. Nevertheless, stillbirths can dramatically contribute to reproductive losses [4]. Risk factors for pregnancy losses are broadly classified into infectious and noninfectious.…”