Bioscientifica Proceedings

Summary. Synchronization of ovulation and subsequent timed artificial insemination became a popular practice in modern, large scale, dairy and beef commercial operations. Popularity was because it became a serious option to eliminate a laborious and low efficiency activity in the industry: checking cows for heat. Synchronization protocols involve the sequential administration of reproductive hormones to manipulate the estrous cycle to provide a fertile oocyte ...

In the current review the main fundamental biological differences in reproductive function between Bos taurus and Bos indicus cattle are discussed. Breed differences regarding puberty, estrous cycle patterns, estrous behavior, acquisition of ovulatory capacity, ovarian structures and reproductive hormones are presented. The main physiological differences that Bos indicus cattle present relative to Bos taurus cattle include: delayed age at pu...

Reduced reproductive efficiency has been reported in high-producing dairy cows. Sources of reproductive inefficiency include decreased expression of estrus, increased diameter of the ovulatory follicle and reduced fertility when cows are inseminated after estrus, increased incidence of double ovulation and twinning, and increased pregnancy loss. To overcome some of these inefficiencies, reproductive management programs have been developed that synchronize ovulation and enable ...

In some situations, the pig has advantages over the mouse as a model in biomedical research. The availability of pluripotent cell lines is likely to broaden this appeal. Here we review progress in the derivation and characterization of embryonic stem cells (ESC) and induced pluripotent lines (iPSC) from pigs. Until recently, most porcine ESC failed to meet the full criteria for pluripotency, but that may be changing as more becomes known about the culture conditions requ...

It is well established that the interferon τ (IFN-τ) family of proteins play a major role in preventing the regression of the corpus luteum during early pregnancy in ruminants, such as cattle, sheep and goats, but not in other mammals. These interferons, which are structurally and functionally related to type I interferon, such as IFN-α and -ω, arose from a duplication of an IFN-ω gene approximately 36 million years ago. The IFN-τ genes have conti...

The second week of pregnancy is a particularly critical period for embryonic survival in pigs. Within that time, conceptus oestrogen synthesis is initiated, spacing and final placement of conceptuses is completed, and the signal for extending the functional lifespan of the corpora lutea is received by the mother. There is also a marked increase in blood flow to the uterus and the uterine endometrium produces and secretes nutrient histotrophe. Coneeptus-derived oestrogen h...

Summary. Ovine and bovine trophoblast protein-1 (oTP-1 and bTP-1) have been strongly implicated as antiluteolytic agents and responsible for maternal recognition of pregnancy in sheep and cattle, respectively. Both are interferons (IFN) belonging to the IFN-α family, but their length (172 residues versus 166 for most IFN-α) places them in an unusual subclass (the IFN-αII). The various isoforms of oTP-1 and bTP-1 produced by trophoblas...

Abstract. During the last decade, transcriptome profiling has emerged as an efficient approach to describe and study cellular functions. The potential to survey transcript abundance for all genes offers promise to shed light on mammalian early embryogenesis. Furthermore, the report of aberrant phenotypes following the application of reproductive technologies also fueled the need to understand how embryos react, cope and adapt to their surrounding microenvironm...

Summary. The progress in understanding the metabolism of the ruminant cumulus-oocyte complex (COC) from large antral follicles has progressed significantly in the past decade. In particular, new insights in the importance of lipid metabolism, ß-oxidation and its relationship to oxidative phosphorylation within oocytes have emerged. This provides opportunities for tapping into the potential yield of ATP from lipid metabolism, as ATP content is a major dete...

Summary. Reproductive traits can range from lowly to moderately heritable. Genomic technologies provide a powerful tool for improving selection for traits that are lowly heritable, sex-linked, or not expressed until later in life. Therefore, as genomic technologies become a part of selection decisions, there is a critical need to understand how specific gene variants affect reproductive traits in cattle. Both classical quantitative genetics approaches and geno...