Showing papers in "Animal Reproduction Science in 2000"

TL;DR: Evidence for new approaches for improving the performance of cryopreserved semen is offered and factors affecting the proportion of survivors and functional status of survivors are reviewed.

TL;DR: Nutritional interactions resulting in poor fertility of high producing dairy cows include the antecedent effects of NEBAL and effects of high dietary protein.

TL;DR: The problems, aspects and methods of liquid storage and freeze-thawing of boar semen are discussed and a review is given on examination of spermatozoa by the recent fluorescent staining methods.

TL;DR: Factors influencing the fertility of stored semen and methods used for improvement are discussed, and fertility results of long-term frozen stored ram semen are given.

TL;DR: The possible roles of cryoprotectants and additives are considered in the context of their putative interactions with the sperm plasma membrane and modern approaches to the laboratory assessment of spermatozoa after freeze-thawing are discussed.

TL;DR: It is suggested that a variety of endocrine regulatory points exist whereby stress limits the efficiency of reproduction, and endocrine evidence to show that stressors interfere with precise timings of reproductive hormone release within the follicular phase.

TL;DR: This review summarizes the ways in which the functioning of various parts of the reproductive system of cows exposed to HS is impaired, including altered follicular dynamics, suppressed production of follicular steroids, and low quality of oocytes and developed embryos.

TL;DR: Suggested control measures focus on programs to reduce the number of congenitally infected animals retained in the herd and to minimize the opportunity for postnatal transmission from the environment.

TL;DR: The historical and current methods used for storage of bovine semen are described and the essential physiological differences between liquid and frozen semen are addressed.

TL;DR: High milk yield, high parity, and calving in winter were risk factors for several reproductive disorders, which delayed insemination and conception in dairy cows, and some of them increased the risk of culling.

TL;DR: A review is given on the use of frozen-thawed semen for artificial insemination (AI) in spontaneous and induced oestrus and factors influencing the fertility.

TL;DR: This review attempts to explain the reasons for the lack of widespread application of vitrification in domestic animal embryology and discusses the theoretical and practical differences between the two technologies as well as their commercial prospects.

TL;DR: Six-day-old non-surgically recovered bovine ova/embryos have been used to evaluate compensable and uncompensable seminal deficiencies as well as to test reproductive strategies, allowing the separation of reproductive failure by fertilization from that by embryonic development.

TL;DR: A coordinated management approach involving herd managers, nutritionists and veterinarians is required to obtain high reproduction efficiency in dairy cows.

TL;DR: Sexed sperm on demand over the next several years will provide livestock producers with many options in seeking to improve efficiency of production and improve quality of products to enhance consumer acceptability.

TL;DR: It is concluded that the alphaT inclusion in the boar semen diluent increased cell viability through its prevention of an oxidative reduction in the levels of the major polyunsaturated fatty acids, namely 22:6n-3.

TL;DR: Methods of semen collection and artificial insemination in poultry, requirement for diluents, methods of liquid and frozen storage of avian semen and evaluation of spermatozoa after storage for fertilizing ability are reviewed.

TL;DR: Compounds such as ethylenediamine tetraacetic acid (EDTA), NaN(3) and 2,4-dinitrophenol have been shown to increase embryo development and quality of resulting embryos, demonstrating that the process of ATP production is a key regulator of in vitro embryo development.

TL;DR: It is postulated that the essence of selection of a dominant follicle in these two species is a close two-way functional coupling between changing FSH concentrations and follicle growth and development.

TL;DR: Results provide new information indicating that most embryo losses in heifers have occurred before day 14 after insemination, which is a major source of financial loss to livestock producers.

TL;DR: The TMR did not correlate with estimated motility but mostly was higher than the latter, which is postulated to be caused by the mobilizing effect of the countercurrent in the transmigration apparature.

TL;DR: Recent reports of prostatic intraepithelial neoplasia (PIN) in a high percentage of older male dogs, with and without prostatic adenocarcinoma, suggests that PIN may be a precursor to adenOCarcinomas in the dog as it is believed to be in man.

TL;DR: How BVDV influences reproductive function, the potential for viral transmission during breeding and the measures that must be taken to avoid the spread of infection to susceptible cattle populations via semen, embryos, culture fluids and infected cows are discussed.

TL;DR: Improvement of IVM, in vitro fertilization (IVF) and embryo culture coupled with ovarian tissue grafting, cryobanking of follicles, oocytes, semen, or embryos, with subsequent ET into surrogate females, may render this technology feasible for use in endangered wild felids.

TL;DR: A plea was made for intensified research efforts, farmer education and quality control of vitamin-mineral pre-mixes, in order to improve micronutrient nutrition, and, consequently, the reproductive performance and overall productivity of farm animals in developing tropical countries.

TL;DR: Ovarian function is central to ovarian function in Bubalus bubalis, particularly, in relation to seasonal changes, and efforts may be directed at understanding the process and temporal pattern of follicular dynamics using techniques which permit serial assessment of changes occurring over time.

TL;DR: Efficiency of spermatogenesis is the estimated number of spermatozoa produced per day per gram of testicular parenchyma, influenced to the amount of germ cell degeneration, pubertal development, season of the year, and aging of humans and animals.

TL;DR: Assays based on in vitro fertilization (IVF) and related techniques such as zona pellucida (ZP) binding assays and oocyte penetration tests, which can provide valuable information about a semen donor, an insemination dose or a method of semen preservation are presented.

TL;DR: In the later stages of an epidemic, there may also be an increase in the number of mummified fetuses, but their prevalence is likely to be far less than during an epidemic of PPV-induced reproductive failure, and a timely and reliable laboratory diagnosis of either disease can be made.

TL;DR: This review has attempted to summarize, based on recent data obtained in the laboratory and elsewhere, the current understanding of the regulatory mechanisms of seasonality and discuss the implications with regard to treatment strategies to advance the onset of cyclic reproductive activity in the early spring.