Showing papers in "Theriogenology in 1997"

TL;DR: It is believed that a 5-point lameness scoring system that assessed gait and placed a novel emphasis on back posture effectively identifies lame cows and should trigger corrective interventions.

TL;DR: The final oocyte maturation up to metaphase II after LH stimulation of the ovulatory follicle is the culmination of the previous processes and equips the oocyte with a haploid chromosomal compartment and the cell biological apparatus specialized for fertilization and initial embryonic development.

TL;DR: In this paper, the authors present summary information from 30 data sets obtained worldwide (WW) on IVP and nuclear transfer in different cattle breeds, plus the preliminary results from a highly controlled field study (FS) undertaken by Holland Genetics (HG) on Holstein-Friesian IVP calves.

TL;DR: In this article, the authors used ultrasonography on cows and heifers of the Nelore breed of Bos indicus cattle to study the growth of the follicle in the first and second stages of the natural or prostaglandin-induced estrous cycle.

TL;DR: The nature of emergence and deviation of follicles during follicular waves in cattle was studied in 3 experiments and it was suggested that the follicle selected to become dominant, as manifested by deviation, is the first follicle to develop to a decisive stage.

TL;DR: Ascorbic acid has protective effects on sperm membrane integrity in diluted stallion semen, which is limited by its relatively short-term fertilizing capacity.

TL;DR: Analysis of the field fertility per cycle results when mares were bred with 300 or 150 x 10(6) total spermatozoa at different frequencies until ovulation indicated that mares that were inseminated 2 times or more per estrus show an improved fertility in comparison with mares inSEminated only once.

TL;DR: Analysis of specific sperm swelling patterns showed that those patterns considered to reflect maximal sperm swelling were indicative of high fertility, and correlation coefficients among the various sperm characteristics and fertility of bulls were highly significant.

TL;DR: Results show the successful in vitro penetration of pig oocytes in a chemically semidefined medium without added bicarbonate, and although BSA and caffeine can modulate the rate of sperm penetration, calcium seems to be an important regulatory ion.

TL;DR: Maternal plasma progesterone concentrations were correlated with interferon-tau production by the conceptuses, suggesting that higher maternal progester one may provide a more suitable environment for the developing conceptus.

TL;DR: The optimal time for insemination was found to be in the interval 28 h before to 4 h after ovulation, with the lowest frequency of non-pregnant sows and the highest total number of piglets born per sow found after insemination.

TL;DR: The addition of Equex STM paste significantly increased the proportion of spermatozoa having an intact plasmalemma immediately after thawing compared with the control and increased the longevity of the thawed spermatozosa, prolonging the maintenance of both motility and plasma membrane integrity.

TL;DR: The side of ovulation was determined correctly in 262 of 286 heifers (92%), and pregnancy rates were nearly identical for ipsilateral and contralateral inseminations.

TL;DR: It is demonstrated that buffalo have estrous cycles with 1, 2 or 3 follicular waves; that 2-wave cycles are the most common; and that the number of waves in a cycle is associated with the luteal phase and with estrous cycle length.

TL;DR: In sheep this has now been achieved with the birth of live lambs from an embryo derived, epithelial like cell line, which will herald a new era in the germ line modification of farm animal species.

TL;DR: It is suggested that bovine oocytes have acquired full meiotic competence at a diameter of 115 microm but not yet attained full developmental competence to blastocysts, and that oocytes has acquired full developmental Competence at aiameter of 120 microm.

TL;DR: Greater lactation feed intake improved the 4 measures of reproductive performance, and longer lactation length and farrowing-to-conception interval were associated with larger subsequent litter size and larger litter weight at weaning.

TL;DR: In vivo-matured porcine oocytes were fertilized in vitro with X and Y chromosome-bearing spermatozoa, and sorted for sex on the basis of DNA content by flow cytometry, and developmental competence of the sexed embryos was determined through established pregnancies after embryo transfer.

TL;DR: It was concluded that transrectal ultrasonographic examination to assess the CTUP and the echogenicity of the fetal fluids is superior to the transabdominal approach and should be added to current diagnostic tools during late gestation.

TL;DR: The findings suggest that HOST is a sensitive and reproducible test to assess the functional integrity of boar sperm membranes after incubation under hypoosmotic stress conditions and may be a useful tool for detecting subpopulations of subviable spermatozoa when used in conjunction with another type of membrane integrity test.

TL;DR: Oocytes cultured in groups are developmentally more competent and suggest that for optimum development oocytes need some undefined paracrine activity that is absent from the culture medium in addition to coculture with granulosa cells, which enhances development to the blastocyst stage of both group and singly cultured oocytes.

TL;DR: The data suggest that differences in the dimensions of sperm heads may exist between fertile and subfertile stallions.

TL;DR: A combination of permeating and nonpermeating cryoprotectants were more effective in preserving rabbit spermatozoa than acetamide alone and that analyzing multiple sperm characteristics, by flow cytometry, can assess sperm damage not detected by analyzing sperm motion characteristics.

TL;DR: Following a modified freezing protocol, epididymal spermatozoa can easily be frozen in small containers for IVF, with higher resultant motility and fertilization rates than with ejaculated semen.

TL;DR: Potential intracellular mechanisms leading to a reduction in PGF 2α secretion are discussed, as are current prospects for manipulating the dialogue to improve embryo survival.

TL;DR: The state of the art on the action of endocrine and paracrine factors that affect the in vitro maturation of bovine oocytes either directly or mediated by cumulus cells are presented.

TL;DR: The fertilization rate of frozen-thawed spermatozoa was significantly lower than that of fresh semen, but it increased with sperm concentration, and the process of cryopreservation significantly decreased intracellular ATP content.

TL;DR: Embryos derived from prepubertal lamb oocytes have reduced developmental potential in vitro but, of those which do reach the blastocyst stage, they have equal capacity to develop to term as embryos derived from adult sheep.

TL;DR: Results indicate that ICSI can be applied successfully to in-vitro matured equine oocytes to increase the fertilization rates and that in vitro cytoplasmic maturation of oocytes issuing from a compact cumulus may not be complete enough to lead to a successful fertilization.

TL;DR: In conclusion, estrus synchronization with the double PG system can reduce fertility, while P4 supplementation for 5 d before the second PG can improve estrous response and overall reproductive performance.