G L Williams

Summary

Publications

  1. ncbi Physiological regulation of maternal behavior in heifers: roles of genital stimulation, intracerebral oxytocin release, and ovarian steroids
    G L Williams
    Animal Reproduction Laboratory, Texas A and M University Agricultural Research Station, Beeville, Texas 78102, USA
    Biol Reprod 65:295-300. 2001
  2. ncbi Leptin and its role in the central regulation of reproduction in cattle
    G L Williams
    Animal Reproduction Laboratory, Texas A and M University Agricultural Research Station, Beeville 78102, USA
    Domest Anim Endocrinol 23:339-49. 2002
  3. ncbi Chronic administration of recombinant ovine leptin in growing beef heifers: effects on secretion of LH, metabolic hormones, and timing of puberty
    M N Maciel
    Animal Reproduction Laboratory, Texas A and M University Agricultural Research Station, Beeville 78102, USA
    J Anim Sci 82:2930-6. 2004
  4. ncbi Regulatory roles of leptin at the hypothalamic-hypophyseal axis before and after sexual maturation in cattle
    D A Zieba
    Animal Reproduction Laboratory, Texas A and M University Agricultural Research Station, Beeville, Texas 78102, USA
    Biol Reprod 71:804-12. 2004
  5. ncbi Effects of leptin on basal and GHRH-stimulated GH secretion from the bovine adenohypophysis are dependent upon nutritional status
    D A Zieba
    Animal Reproduction Laboratory, Texas A and M University Agricultural Research Station, Beeville, Texas 78102, USA
    J Endocrinol 178:83-9. 2003
  6. ncbi Evidence that lamprey GnRH-III does not release FSH selectively in cattle
    M Amstalden
    Animal Reproduction Laboratory, Texas A and M University Agricultural Research Station, Beeville, Texas 78102, USA
    Reproduction 127:35-43. 2004
  7. ncbi Age at puberty, total fat and conjugated linoleic acid content of carcass, and circulating metabolic hormones in beef heifers fed a diet high in linoleic acid beginning at four months of age
    M R Garcia
    Animal Reproduction Laboratory, Texas A and M University Agricultural Research Station, Beeville 78102, USA
    J Anim Sci 81:261-8. 2003
  8. ncbi Evaluation of vaginal electrical resistance as an indicator of follicular maturity and suitability for timed artificial insemination in beef cows subjected to a synchronization of ovulation protocol
    J F Zuluaga
    Animal Reproduction Laboratory, Texas A and M University Agricultural Research Station, Beeville, TX 78102, USA
    Anim Reprod Sci 109:17-26. 2008
  9. ncbi Continuous administration of low-dose GnRH in mares II. Pituitary and ovarian responses to uninterrupted treatment beginning near the autumnal equinox and continuing throughout the anovulatory season
    S M Collins
    Animal Reproduction Laboratory, Texas A and M University Agricultural Research Station, Beeville, TX 78102, USA
    Theriogenology 68:673-81. 2007
  10. doi Presynchronization with gonadotropin-releasing hormone increases the proportion of Bos indicus-influenced females ovulating at initiation of synchronization but fails to improve synchronized new follicular wave emergence or fixed-time artificial inseminat
    J F Zuluaga
    Animal Reproduction Laboratory, Texas AgriLife Research, Beeville 78102, USA
    J Anim Sci 88:1663-71. 2010

Collaborators

Detail Information

Publications26

  1. ncbi Physiological regulation of maternal behavior in heifers: roles of genital stimulation, intracerebral oxytocin release, and ovarian steroids
    G L Williams
    Animal Reproduction Laboratory, Texas A and M University Agricultural Research Station, Beeville, Texas 78102, USA
    Biol Reprod 65:295-300. 2001
    ..Combinations of hormonal, sensory, olfactory, and visual cues observed previously to induce maternal behavior in nulliparous ewes do not appear adequate for induction of maternal behavior in nulliparous heifers...
  2. ncbi Leptin and its role in the central regulation of reproduction in cattle
    G L Williams
    Animal Reproduction Laboratory, Texas A and M University Agricultural Research Station, Beeville 78102, USA
    Domest Anim Endocrinol 23:339-49. 2002
    ..Additional work to more fully characterize these roles is clearly warranted and could lead to the development of novel strategies for modifying reproductive potential in food-producing species...
  3. ncbi Chronic administration of recombinant ovine leptin in growing beef heifers: effects on secretion of LH, metabolic hormones, and timing of puberty
    M N Maciel
    Animal Reproduction Laboratory, Texas A and M University Agricultural Research Station, Beeville 78102, USA
    J Anim Sci 82:2930-6. 2004
    ..Characteristics of GnRH-induced release of LH were not affected by treatment. In summary, chronically administered leptin failed to induce puberty or alter endocrine characteristics in beef heifers nearing the time of expected puberty...
  4. ncbi Regulatory roles of leptin at the hypothalamic-hypophyseal axis before and after sexual maturation in cattle
    D A Zieba
    Animal Reproduction Laboratory, Texas A and M University Agricultural Research Station, Beeville, Texas 78102, USA
    Biol Reprod 71:804-12. 2004
    ..However, leptin-mediated augmentation of LH concentrations and pulse amplitude in the nutritionally stressed, mature female are associated with modifications in GnRH secretory dynamics...
  5. ncbi Effects of leptin on basal and GHRH-stimulated GH secretion from the bovine adenohypophysis are dependent upon nutritional status
    D A Zieba
    Animal Reproduction Laboratory, Texas A and M University Agricultural Research Station, Beeville, Texas 78102, USA
    J Endocrinol 178:83-9. 2003
    ..In fasted cows, oleptin had no stimulatory effect on GHRH-induced GH release. Results show that leptin can act directly at the anterior pituitary level to modulate GH release, and this effect is dependent upon nutritional history...
  6. ncbi Evidence that lamprey GnRH-III does not release FSH selectively in cattle
    M Amstalden
    Animal Reproduction Laboratory, Texas A and M University Agricultural Research Station, Beeville, Texas 78102, USA
    Reproduction 127:35-43. 2004
    ..001) LH but not FSH. These findings suggest that lGnRH-III may act as a weak competitor for the mGnRH receptor and do not support the hypothesis that it selectively releases FSH in cattle...
  7. ncbi Age at puberty, total fat and conjugated linoleic acid content of carcass, and circulating metabolic hormones in beef heifers fed a diet high in linoleic acid beginning at four months of age
    M R Garcia
    Animal Reproduction Laboratory, Texas A and M University Agricultural Research Station, Beeville 78102, USA
    J Anim Sci 81:261-8. 2003
    ..Results indicate that diets high in linoleic acid fed to growing beef heifers beginning early in life have little or no effect on total carcass fat, circulating leptin, or age at puberty despite measurable increases in CLA accumulation...
  8. ncbi Evaluation of vaginal electrical resistance as an indicator of follicular maturity and suitability for timed artificial insemination in beef cows subjected to a synchronization of ovulation protocol
    J F Zuluaga
    Animal Reproduction Laboratory, Texas A and M University Agricultural Research Station, Beeville, TX 78102, USA
    Anim Reprod Sci 109:17-26. 2008
    ....
  9. ncbi Continuous administration of low-dose GnRH in mares II. Pituitary and ovarian responses to uninterrupted treatment beginning near the autumnal equinox and continuing throughout the anovulatory season
    S M Collins
    Animal Reproduction Laboratory, Texas A and M University Agricultural Research Station, Beeville, TX 78102, USA
    Theriogenology 68:673-81. 2007
    ..Continuous infusion of low-dose GnRH, beginning soon after autumnal equinox and continuing until just after vernal equinox, failed to prevent the occurrence of or to hasten transition from seasonal anovulation...
  10. doi Presynchronization with gonadotropin-releasing hormone increases the proportion of Bos indicus-influenced females ovulating at initiation of synchronization but fails to improve synchronized new follicular wave emergence or fixed-time artificial inseminat
    J F Zuluaga
    Animal Reproduction Laboratory, Texas AgriLife Research, Beeville 78102, USA
    J Anim Sci 88:1663-71. 2010
    ..4). Presynchronization increased the proportion of females ovulating after GnRH-1, but this did not increase synchrony of new follicular wave emergence or ovulation after GnRH-2, and did not improve TAI pregnancy rates...
  11. ncbi Leptin attenuates the acute effects of centrally administered neuropeptide Y on somatotropin but not gonadotropin secretion in ovariectomized cows
    M R Garcia
    Animal Reproduction Laboratory, Texas A and M University Agricultural Research Station, Hwy 59E, Beeville, TX 78102 9410, USA
    Domest Anim Endocrinol 26:189-200. 2004
    ..Treatments had no effect on FSH secretion. Results confirm suppressive and stimulatory effects of NPY on LH and GH secretion, respectively, and indicate that leptin can attenuate the acute effects of NPY on GH secretion in cattle...
  12. ncbi Effects of leptin on gonadotropin-releasing hormone release from hypothalamic-infundibular explants and gonadotropin release from adenohypophyseal primary cell cultures: further evidence that fully nourished cattle are resistant to leptin
    M Amstalden
    Animal Reproduction Laboratory, Texas A and M University Agricultural Research Station, Beeville, TX 78102 9410, USA
    Anim Reprod Sci 85:41-52. 2005
    ..Results support the hypothesis that leptin has limited effects on the release of GnRH and gonadotropins in full-fed cattle and reiterate important species differences in responsiveness to leptin...
  13. ncbi Leptin prevents fasting-mediated reductions in pulsatile secretion of luteinizing hormone and enhances its gonadotropin-releasing hormone-mediated release in heifers
    M N Maciel
    Animal Reproduction Laboratory, Texas A and M University Agricultural Research Station, Beeville, Texas 78102, USA
    Biol Reprod 70:229-35. 2004
    ..Results indicate, for the first time, that exogenous leptin can prevent fasting-mediated reductions in the frequency of LH pulses and modify GnRH-mediated release of LH in intact, prepubertal heifers...
  14. ncbi Leptin acts at the bovine adenohypophysis to enhance basal and gonadotropin-releasing hormone-mediated release of luteinizing hormone: differential effects are dependent upon nutritional history
    M Amstalden
    Animal Reproduction Laboratory, Texas A and M University Agricultural Research Station, Beeville, Texas 78102, USA
    Biol Reprod 69:1539-44. 2003
    ..These observations support the hypothesis that leptin modulates the secretion of LH in mature cows, to a large extent, by its direct actions at the AP. Differential manifestations of these effects are dependent upon nutritional history...
  15. ncbi Central infusion of recombinant ovine leptin normalizes plasma insulin and stimulates a novel hypersecretion of luteinizing hormone after short-term fasting in mature beef cows
    M Amstalden
    Animal Reproduction Laboratory, Texas A and M University Agricultural Research Station, 3507 Highway 59 E, Beeville, TX 78102, USA
    Biol Reprod 66:1555-61. 2002
    ....
  16. doi Reproductive seasonality in the mare: neuroendocrine basis and pharmacologic control
    G L Williams
    Animal Reproduction Laboratory, Texas AgriLife Research, Beeville, TX 78102, USA
    Domest Anim Endocrinol 43:103-15. 2012
    ..However, its practical exploitation continues to await the development of a commercially acceptable delivery vehicle...
  17. ncbi Ovarian, hormonal, and reproductive events associated with synchronization of ovulation and timed appointment breeding of Bos indicus-influenced cattle using intravaginal progesterone, gonadotropin-releasing hormone, and prostaglandin F2alpha
    J P Saldarriaga
    Animal Reproduction Laboratory, Texas A and M University Agricultural Research Station, Beeville 78102, USA
    J Anim Sci 85:151-62. 2007
    ....
  18. doi Secretion of luteinizing hormone into pituitary venous effluent of the follicular and luteal phase mare: novel acceleration of episodic release during constant infusion of gonadotropin-releasing hormone
    I C Velez
    Animal Reproduction Laboratory, Texas AgriLife Research, Beeville, TX 78102 8571, USA
    Domest Anim Endocrinol 42:121-8. 2012
    ..These observations appear to be unique to the horse. Further studies that exploit this experimental model are likely to reveal novel mechanisms regulating the control of gonadotrope function in this species...
  19. doi Pharmacologic application of native GnRH in the winter anovulatory mare, II: accelerating the timing of pregnancy
    J F Thorson
    Animal Reproduction Laboratory, Texas A and M AgriLife Research, Beeville, Texas, USA Department of Animal Science, Texas A and M University, College Station, Texas, USA
    Theriogenology 81:625-31. 2014
    ....
  20. ncbi Regulatory roles of leptin in reproduction and metabolism: a comparative review
    D A Zieba
    Animal Reproduction Laboratory, Texas A and M University Agricultural Research Station, 3507 Hwy 59E, Beeville, TX 78102, USA
    Domest Anim Endocrinol 29:166-85. 2005
    ..Future therapeutic uses for recombinant leptin that exploit states of nutritional hypersensitization, and identification of genetic markers for genotypic variation in leptin resistance, are currently under investigation...
  21. ncbi High-pressure steam sterilization of previously used CIDR inserts enhances the magnitude of the acute increase in circulating progesterone after insertion in cows
    J F Zuluaga
    Animal Reproduction Laboratory, Texas A and M University, Agricultural Research Station, 3507 Hwy 59E, Beeville, TX 78102 8571, USA
    Anim Reprod Sci 107:30-5. 2008
    ..6+/-0.5) and DIS (2.7+/-0.3) markedly. Autoclaving may be the best option when re-using CIDR inserts because it creates greater concentrations of P4 immediately after insertion and reduces maximally the risk of disease transmission...
  22. doi Gene expression in the arcuate nucleus of heifers is affected by controlled intake of high- and low-concentrate diets
    C C Allen
    Animal Reproduction Laboratory, Texas AgriLife Research, Beeville 78102
    J Anim Sci 90:2222-32. 2012
    ..In summary, dietary treatments shown previously to accelerate the timing of pubertal onset in heifers increased ruminal propionate, promoted enhanced metabolic hormone secretion, and altered gene expression in the ARC...
  23. ncbi Comparison of three approaches for synchronization of ovulation for timed artificial insemination in Bos indicus-influenced cattle managed on the Texas gulf coast
    S W Williams
    Animal Reproduction Laboratory, Texas A and M University Agricultural Research Station, Beeville 78102 9410, USA
    J Anim Sci 80:1173-8. 2002
    ..However, in nulliparous Brahman-influenced heifers that are confirmed to be pubertal, NP may be superior to the other two treatments for timed AI...
  24. doi Pharmacologic application of native GnRH in the winter anovulatory mare, I: frequency of reversion to the anovulatory state following ovulation induction and cessation of treatment
    J F Thorson
    Animal Reproduction Laboratory, Texas A and M AgriLife Research, Beeville, Texas, USA Department of Animal Science, Texas A and M University, College Station, Texas, USA
    Theriogenology 81:579-86. 2014
    ..This will improve the likelihood of a normal interovulatory interval after treatment withdrawal. ..
  25. ncbi Continuous administration of low-dose GnRH in mares I. Control of persistent anovulation during the ovulatory season
    G L Williams
    Animal Reproduction Laboratory, Texas A and M University Agricultural Research Station, Beeville, TX 78102, USA
    Theriogenology 68:67-75. 2007
    ..Thereafter, cumulative ovulation frequency (85%), pregnancy (72%) and cycles/conception (1.3+/-0.2) were similar between groups; however, interval to conception was reduced (P<0.01) by 10.3 d in GnRH/GnRH compared to Control/GnRH...
  26. ncbi Serum leptin and its adipose gene expression during pubertal development, the estrous cycle, and different seasons in cattle
    M R Garcia
    J Anim Sci 80:2158-67. 2002
    ..Seasonal effects on circulating leptin observed in mature cows from winter to summer could also plausibly account for a portion of the prepubertal rise in serum leptin observed in heifers...