Response to Therapeutic Abortion in Lactating Dairy Cows Carrying Dead Twins during the Late Embryo/Early Fetal Period.

Fernando López-Gatius

doi:10.3390/ani11092508

Abstract

Simple SummaryThe presence of dead embryos/fetuses can be precisely detected around 60 days post-insemination in dairy cattle. Little information on the fate of dead twins has been published. Practitioners usually apply a therapeutic abortion using prostaglandin F2α (PGF2α) or its analogs to reduce the associated extended interval to estrus. This study evaluated the dose–response effect of PGF2α inducing abortion in cows with two dead twins at pregnancy diagnosis 28–34 days post-AI (late embryonic period) or at confirmation of pregnancy 49–55 days post-AI (early fetal period). An increased PGF2α dose had no influence on the induction of abortion and the induced abortion rate was inversely associated with milk production during the late embryonic period, whereas an increased PGF2α dose was found to offer improvements during the early fetal period.This study examined the dose–response effect of prostaglandin F2α (PGF2α) when used to induce abortion in cows with two dead twins at pregnancy diagnosis 28–34 days post-AI (late embryonic period: LE) or at pregnancy confirmation 49–55 days post-AI (early fetal period: EF). The study population consisted of 415 cows receiving a single PGF2α dose (PG1 group: 254 LE and 161 EF cows) and 200 receiving a 1.5 × PGF2α dose (PG1.5 group: 121 LE and 79 EF cows). The induced abortion rate was significantly lower (chi-square test; p < 0.0001) in the EF (34.6%) than LE cows (88%), and was also reduced (p = 0.001) in the EF PG1 group (28%) compared with the EF PG1.5 group (48.1%). High milk production (≥45 kg) was the only factor influencing the induced abortion rate in LE cows (odds ratio 0.2; p < 0.0001), whereas the odds ratio for induced abortion of PG1.5 cows was 2.3 (p = 0.005) in EF cows. In conclusion, an increased PGF2α dose had no effect on abortion induction during the late embryonic period and its rate was inversely associated with milk production. This higher PGF2α dose did, however, offer benefits during the early fetal period.

Highlights

IntroductionMainly occurs before day 60 of gestation [1,2,3,4], when implantation is firmly established [5,6]
In cattle, pregnancy loss after its diagnosis 28–34 days post-artificial insemination (AI)mainly occurs before day 60 of gestation [1,2,3,4], when implantation is firmly established [5,6].During this time interval covering the late embryo/early fetal period, the chances of losses are much lower [1]
An increased prostaglandin F2α (PGF2α) dose had no effect on abortion induction during the late embryonic period and its rate was inversely associated with milk production

Summary

Introduction

Mainly occurs before day 60 of gestation [1,2,3,4], when implantation is firmly established [5,6] During this time interval covering the late embryo/early fetal period, the chances of losses are much lower [1]. In high producing dairy herds, the incidence of pregnancy loss can exceed 20% [2,3,4] and has a major economic impact [8] This means that a pregnancy assessment following its diagnosis is usually scheduled for around 60 days post-AI. An important problem is that gestation markers are lost in most cows, and a cow is recorded as non-pregnant when the second diagnosis is negative During this period, the presence of dead embryos/fetuses can be precisely detected, in multiple pregnancies. To reduce the extended interval to estrus associated with conceptus death, practitioners usually treat cows with prostaglandin

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