Bioscientifica Proceedings

The introduction of high-density SNP arrays in livestock species has enabled genomic evaluations on a scale not possible just a few years ago. Faster genetic gains are realized from application of genomics in pigs by increasing the accuracy of selection. This is especially important for lowly heritable reproductive traits, where female selection candidates have not yet expressed a phenotype at the point of selection and male candidates have no phenotype at all. Litter si...

All reproductive processes involve one or more of the protein hormones secreted from the anterior pituitary gland: LH, FSH, prolactin, growth hormone, ACTH and thyroidstimulating hormone (TSH). Primary hormones of reproduction, such as LH and FSH, directly regulate a reproductive activity. For example, LH and FSH stimulate follicular growth and the associated secretion of oestradiol in sows. In contrast, secondary hormones of reproduction such as TSH are permissive and re...

Although mouse embryonic stem cells have been used widely for over a decade as an important tool for introducing precise genetic modification into the genome, demonstrating the great value of this technology in a range of biomedical applications, similar technology does not exist for domestic animals. However, the development of somatic cell nuclear transfer has bypassed the need for embryonic stem cells from livestock. The production of offspring from differentiated cel...

Transplantation of germ cells from fertile donor mice to the testes of infertile recipient mice results in donor-derived spermatogenesis and transmission of the donor haplotype to offspring of recipient animals. In the pig, germ cells can be transplanted to a recipient testis by ultrasoundguided cannulation of the rete testis with delivery of cells by gravity flow. It is important to note that germ cell transplantation was successful between unrelated, immuno-competent p...

The autocrine and paracrine role of the insulin-like growth factors (IGFs) and epiderrnal growth factor (EGF)-related peptides in pig ovary are reviewed. For convenience, each of these regulatory systems is divided into several interactive components: regulated expression of the growth factors, growth factor reception at the cell surface and intracellular action of the growth factors. In addition, the concept of regulated bioavailability and targeting of growth factors in...

The resumption of ovarian follicular development during lactation and after weaning in sows is a complex process that ultimately determines rebreeding efficiency of sows. Ovarian follicular development before weaning is heterogeneous because multiple patterns of development are observed when individual sows are compared. Sows can have relatively inactive ovaries before weaning with follicles of < 2 mm in diameter. Other sows have nonovulatory follicular waves in which...

In this paper we review three intra-luteal factors and their roles in the corpus luteum (CL). Insulin-like growth factor (IGF)-I, together with its receptor and IGF-binding proteins (IGFBPs), represent an important control system in the CL. IGF-I is a product of small luteal cells and has steroidogenic (i.e. luteotrophic) actions on large luteal cells via the type I receptor, while IGFBPs (e.g. BP-2 and 3; small cells) generally inhibit IGF-Is actions. IGF-I is particula...

Summary. Behavioural responses can have direct effects on reproduction when the performance of the behaviour contributes to productivity (e.g. achievement of copulation). Alternatively, there are indirect effects where a behavioural change is insufficient to allow adaptation to an environmental change and so the animal has to resort to physiological mechanisms with potential adverse effects on productivity.Boar contact has substantial ...

The occurrence of puberty in the female is due to the interplay of central and peripheral mechanisms in which the hypothalamic-pituitary-ovarian axis regulates growth and gonadal function, as well as adipocyte hormone secretion. Hypothalamic GnRH mRNA expression increased at 3.5 months of age and declined by 6 months of age. Concomitant with the age related reduction in the oestrogen negative feedback on LH secretion was a decline in hypothalamic oestrogen receptor-&alph...

Abstract unavailableKeywords: gene transfer; gene modification; gene expression; livestock; transgenic animal© 1991 Journals of Reproduction & Fertility Ltd...