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

Advances in Dairy Cattle Reproduction-A Foreword

Dairy cattle have played an important role in economic development since the beginning of agriculture [...].

Histopathology of fused triplet placenta in rat

A fused triplet placenta was observed in a Wistar Hannover rat on gestation day 15. Each placenta (referred to as PL-A, PL-B, and PL-C) of this fused placenta was attached to one fetus each, but their fetal weights were lower than that of the fetus attached to the only normal placenta (referred to as PL-N) in this dam. Histopathologically, thinning of the trophoblastic septa and dilatation of the maternal sinusoid in the labyrinth zone were observed in PL-B and PL-C, but not in PL-A or PL-N. The points of placental fusion were at the junctional zone derived from each side of the placenta without connective tissues, and the septum was composed of trophoblastic giant cells. Although PL-A had a solitary metrial gland, PL-B and PL-C shared one metrial gland with one spiral artery terminus branching towards each labyrinth zone.

Clinical management of pregnancy-related problems between days 28 and 60 in the dairy cow

The biological and economic impacts of pregnancy loss in dairy herds are well recognized. This review examines clinical aspects of late embryonic/early fetal loss of non-infectious cause in the dairy cow. The period of interest spans from shortly after observation of at least one embryo with a heartbeat upon pregnancy diagnosis, at around Day 28 of pregnancy (late embryonic period), until approximately Day 60 of pregnancy (early fetal period). This last time point is when pregnancy is firmly established and beyond which the risk of pregnancy loss is greatly reduced. We particularly focus on the role of the clinician in managing a pregnancy and discuss findings to predict the viability of a pregnancy, available therapies for expected pregnancy problems and possible implications of the newer technologies.

Meta-analysis of the incidence of pregnancy losses in dairy cows at different stages to 90 days of gestation

Pregnancy losses are a biological challenge and economically important in dairy herds. A meta-analysis was conducted to quantify losses in 4 periods from 19 to 90 d of pregnancy corresponding to the physiological development of gestation in dairy cows. A total of 19,723 diagnostic records from 46 studies were included. Pregnancy losses averaged 27%, 13%, 7%, and 2% in the early embryonic (19 to 32 d), late embryonic (30 to 45 d), early fetal (45 to 60 d), and later fetal (60 to 90 d) stages. These results provide a formal synthesis of the incidence of pregnancy losses in dairy cows.

Ovarian response to prostaglandin F2α in lactating dairy cows: a clinical update

Prostaglandin F_2α (PGF_2α) and its analogs are used to induce luteolysis in estrus synchronization programs to terminate unwanted pregnancies or to promote ovulation in certain cow subpopulations. In the past few decades, the luteolytic dose of PGF_2α has remained unchanged. This review explores the clinical implications of increasing the standard dose for these applications in high-producing dairy cows. Ultrasonography may assist in selecting the most appropriate PGF_2α dose and improve the results. A reference has been used for PGF_2α for promoting ovulation in herds showing poor reproductive performance.