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

North American perspectives for cattle production and reproduction for the next 20 years

Ruminant species are important to human society due to their ability to convert human-inedible sources of energy and protein to human-edible food. Greater efficiency of meat and milk production will require the management of the complex reproductive biology of many cattle with a limited capacity and limited budget within a smaller, hotter, and more climatically erratic land area. The over-riding drivers of new reproductive technologies in North America will be smaller economic margins, larger herd size, fewer agricultural workers per farm, and a greater reliance on automation to offset the reduced agricultural labor force. Climate change and the possibility that consumers may dictate the procedures used for animal reproductive management may present additional challenges. The successes of the past 20 years (timed AI, genomic selection for fertility in both bulls and cows, automated estrus detection, chemical and ultrasonographic pregnancy diagnosis, and gender selected semen) will be improved upon in the next 20 years as most of these technologies can be optimized further. Improving embryo technologies and increasing our understanding of embryonic loss may provide the greatest challenges for the future. Researchers must attempt to devise practical methods to release more follicles from the primordial follicle pool so that a greater number of oocytes and embryos can be harvested from individual animals. Embryonic loss continues to be an unsolved question that cuts the total number of potential offspring by nearly one-third. The identification of fertile embryos in vitro, better methods of cryopreservation, and the optimization of methods of transfer into recipient animals may improve the efficiency of advanced embryo technologies. The derivation of oocytes, sperm, and embryos from pluripotent stem cells may yield a vast supply of gametes and embryos from genetically superior animals and radically change the reproductive management in the future.

Advances in Dairy Cattle Reproduction-A Foreword

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

Evaluation of a Commercial Pregnancy Test Using Blood or Plasma Samples in High-Producing Dairy Cows

This study evaluated a commercial pregnancy-associated glycoproteins (PAGs)-based pregnancy test using whole blood or plasma samples during early pregnancy (28-55 days of gestation) in high-producing dairy cows. Transrectal ultrasonography was used as the gold standard method. The study population constituted of 284 cows. False positive diagnoses were recorded from Day 60 to 89 and from Day 60 to 99 postpartum in blood and plasma samples, respectively. In early pregnancy screening, correct positive diagnoses were recorded in 75% and 100% of blood and plasma samples, respectively. High milk production was associated with negative results in blood samples and with the lowest test line intensity in plasma samples. False positive or negative diagnoses were recorded in 0% of both types of samples in cows previously diagnosed as pregnant and showing signs of estrus. In conclusion, the use of plasma was more effective than the use of blood in early pregnancy diagnosis. In cows previously diagnosed as pregnant and showing signs of estrus, both types of samples showed the same results. Because of large individual variations, normal single pregnancies could not be differentiated from twin pregnancies, from pregnancies with a recently dead conceptus, or from pregnancies that experienced subsequent pregnancy loss.

Recent advances in early pregnancy loss diagnosis in dairy cows: New approaches

Early pregnancy loss is a primary cause of low reproductive rates in dairy cows, posing severe economic losses to dairy farming. The accurate diagnosis of dairy cows with early pregnancy loss allows for oestrus synchronization, shortening day open, and increasing the overall conception rate of the herd. Several techniques are available for detecting early pregnancy loss in dairy cows, including rectal ultrasound, circulating blood progesterone, and pregnancy-associated glycoproteins (PAGs). Yet, there is a need to improve on existing techniques and develop novel strategies to identify cows with early pregnancy loss accurately. This manuscript reviews the applications of rectal ultrasound, circulating blood progesterone concentration, and PAGs in the diagnosis of pregnancy loss in dairy cows. The manuscript also discusses the recent progress of new technologies, including colour Doppler ultrasound (CDUS), interferon tau-induced genes (ISGs), and exosomal miRNA in diagnosing pregnancy loss in dairy cows. This study will provide an option for producers to re-breed cows with pregnancy loss, thereby reducing the calving interval and economic costs. Meanwhile, this manuscript might also act as a reference for exploring more economical and precise diagnostic technologies for early pregnancy loss in dairy cows.