N C Rawlings

Summary

Affiliation: University of Saskatchewan
Country: Canada

Publications

  1. ncbi request reprint Effects of the pesticides carbofuran, chlorpyrifos, dimethoate, lindane, triallate, trifluralin, 2,4-D, and pentachlorophenol on the metabolic endocrine and reproductive endocrine system in ewes
    N C Rawlings
    Department of Veterinary Physiological Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada
    J Toxicol Environ Health A 54:21-36. 1998
  2. ncbi request reprint Ovarian responses in gonadotrophin-releasing hormone-treated anoestrous ewes: follicular and endocrine correlates with luteal outcome
    P M Bartlewski
    Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada
    Reprod Fertil Dev 13:133-42. 2001
  3. ncbi request reprint Does injection of prostaglandin F(2alpha) (PGF2alpha) cause ovulation in anestrous Western White Face ewes?
    K L Davies
    Department of Veterinary Biomedical Sciences, WCVM, University of Saskatchewan, 52 Campus Drive, Saskatoon, Sask, Canada S7N 5B4
    Theriogenology 66:251-9. 2006
  4. doi request reprint Synchronization of follicular wave emergence in the seasonally anestrous ewe: the effects of estradiol with or without medroxyprogesterone acetate
    D M W Barrett
    Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan, Canada S7N 5B4
    Theriogenology 69:827-36. 2008
  5. doi request reprint Characteristics of peaks in serum concentrations of follicle-stimulating hormone and estradiol, and follicular wave dynamics during the interovulatory interval in cyclic ewes
    B M Toosi
    Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
    Theriogenology 73:1192-201. 2010
  6. doi request reprint Ovarian antral follicular dynamics in sheep revisited: comparison among estrous cycles with three or four follicular waves
    S V Seekallu
    Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada
    Theriogenology 73:670-80. 2010
  7. ncbi request reprint Ultrasound and endocrine evaluation of the ovarian response to a single dose of 500 IU of eCG following a 12-day treatment with progestogen-releasing intravaginal sponges in the breeding and nonbreeding seasons in ewes
    D M W Barrett
    Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada S7N 5B4
    Theriogenology 61:311-27. 2004
  8. ncbi request reprint Short- and long-term effects of unilateral ovariectomy in sheep: causative mechanisms
    R Duggavathi
    Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada
    Biol Reprod 78:490-6. 2008
  9. doi request reprint The effect of parity of the dam on sexual maturation, serum concentrations of metabolic hormones and the response to luteinizing hormone releasing hormone in bull calves
    E T Bagu
    Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada
    Reprod Domest Anim 45:803-10. 2010
  10. ncbi request reprint Use of high-resolution transrectal ultrasonography to assess changes in numbers of small ovarian antral follicles and their relationships to the emergence of follicular waves in cyclic ewes
    R Duggavathi
    Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, S7N 5B4 Saskatchewan, Canada
    Theriogenology 60:495-510. 2003

Collaborators

Detail Information

Publications29

  1. ncbi request reprint Effects of the pesticides carbofuran, chlorpyrifos, dimethoate, lindane, triallate, trifluralin, 2,4-D, and pentachlorophenol on the metabolic endocrine and reproductive endocrine system in ewes
    N C Rawlings
    Department of Veterinary Physiological Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada
    J Toxicol Environ Health A 54:21-36. 1998
    ..Data suggest that several currently used pesticides could influence serum concentrations of reproductive and metabolic hormones, particularly thyroxine, the major secretory product of the thyroid and a principal regulator of metabolism...
  2. ncbi request reprint Ovarian responses in gonadotrophin-releasing hormone-treated anoestrous ewes: follicular and endocrine correlates with luteal outcome
    P M Bartlewski
    Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada
    Reprod Fertil Dev 13:133-42. 2001
    ..Both the amplitude of episodic elevations in daily serum FSH concentrations and the characteristics of the pre-ovulatory LH surge may be important for luteogenesis following ovulation...
  3. ncbi request reprint Does injection of prostaglandin F(2alpha) (PGF2alpha) cause ovulation in anestrous Western White Face ewes?
    K L Davies
    Department of Veterinary Biomedical Sciences, WCVM, University of Saskatchewan, 52 Campus Drive, Saskatoon, Sask, Canada S7N 5B4
    Theriogenology 66:251-9. 2006
    ....
  4. doi request reprint Synchronization of follicular wave emergence in the seasonally anestrous ewe: the effects of estradiol with or without medroxyprogesterone acetate
    D M W Barrett
    Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan, Canada S7N 5B4
    Theriogenology 69:827-36. 2008
    ..0-4d) compared to ewes given MAP alone. All ewes given eCG ovulated 3-4d after injection; this predictable time of ovulation may be efficacious for AI and embryo transfer...
  5. doi request reprint Characteristics of peaks in serum concentrations of follicle-stimulating hormone and estradiol, and follicular wave dynamics during the interovulatory interval in cyclic ewes
    B M Toosi
    Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
    Theriogenology 73:1192-201. 2010
    ....
  6. doi request reprint Ovarian antral follicular dynamics in sheep revisited: comparison among estrous cycles with three or four follicular waves
    S V Seekallu
    Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada
    Theriogenology 73:670-80. 2010
    ..In this study, there were no apparent endocrine or follicular characteristics that could explain the regulation of the different number of follicular waves (three vs. four) during cycles of similar length...
  7. ncbi request reprint Ultrasound and endocrine evaluation of the ovarian response to a single dose of 500 IU of eCG following a 12-day treatment with progestogen-releasing intravaginal sponges in the breeding and nonbreeding seasons in ewes
    D M W Barrett
    Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada S7N 5B4
    Theriogenology 61:311-27. 2004
    ..However, eCG treatment increased serum concentrations of estradiol during the periovulatory period, particularly in anestrous ewes; this probably resulted in the synchronous estrus and ovulation in anestrous ewes...
  8. ncbi request reprint Short- and long-term effects of unilateral ovariectomy in sheep: causative mechanisms
    R Duggavathi
    Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada
    Biol Reprod 78:490-6. 2008
    ..Further studies are required to examine the potential role of the nervous system in the enhancement of the life span of the ovulatory-sized follicles leading to ovulatory compensation by the unpaired ovary in ULO sheep...
  9. doi request reprint The effect of parity of the dam on sexual maturation, serum concentrations of metabolic hormones and the response to luteinizing hormone releasing hormone in bull calves
    E T Bagu
    Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada
    Reprod Domest Anim 45:803-10. 2010
    ..Serum LH responses to LHRH at 15 and 25 weeks of age, in calves born to multiparous dams, show some promise for development into a test to select early maturing bull calves...
  10. ncbi request reprint Use of high-resolution transrectal ultrasonography to assess changes in numbers of small ovarian antral follicles and their relationships to the emergence of follicular waves in cyclic ewes
    R Duggavathi
    Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, S7N 5B4 Saskatchewan, Canada
    Theriogenology 60:495-510. 2003
    ..Thus, unlike in cattle, there is no apparent increase in numbers of small follicles at follicle wave emergence in cyclic sheep, and little evidence for selection of recruited follicles and follicular dominance...
  11. ncbi request reprint Effects of medroxyprogesterone acetate (MAP) on ovarian antral follicle development, gonadotrophin secretion and response to ovulation induction with gonadotrophin-releasing hormone (GnRH) in seasonally anoestrous ewes
    P M Bartlewski
    Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Sask, Saskatoon, Canada S7N 5B4
    Anim Reprod Sci 81:63-75. 2004
    ..Ovulatory response and CL formation were increased when GnRH was administered 24 h after sponge removal...
  12. ncbi request reprint The effect of the manipulation of follicle-stimulating hormone (FSH)-peak characteristics on follicular wave dynamics in sheep: does an ovarian-independent endogenous rhythm in FSH secretion exist?
    R Duggavathi
    Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5B4
    Biol Reprod 72:1466-74. 2005
    ....
  13. pmc Evaluation of the ultrasound image attributes of developing ovarian follicles in the four follicular waves of the interovulatory interval in ewes
    B M Toosi
    Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
    Theriogenology 72:902-9. 2009
    ..Changes in image attributes of the follicular wall and antrum indicate potential morphologic and functional differences among antral follicles emerging at different stages of the interovulatory interval in cyclic ewes...
  14. ncbi request reprint Changes in serum luteinizing hormone (LH) concentrations in response to luteinizing hormone releasing hormone (LHRH) in bull calves that attained puberty early or late
    E T Bagu
    Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, 52 Campus Drive, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5B4
    Theriogenology 66:937-44. 2006
    ....
  15. ncbi request reprint Postnatal changes in testicular gonadotropin receptors, serum gonadotropin, and testosterone concentrations and functional development of the testes in bulls
    E T Bagu
    Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, Saskatchewan, Canada S7N 5B4
    Reproduction 132:403-11. 2006
    ..05). High concentrations of gonadotropins and their receptors may be critical to initiate testis growth postnatally and support it after 25 weeks of age in the face of low serum gonadotropin concentrations...
  16. ncbi request reprint Computer assisted image analyses of corpora lutea in relation to peripheral concentrations of progesterone: a comparison between breeds of sheep with different ovulation rates
    K L Davies
    Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, Sask, Canada S7N 5B4
    Anim Reprod Sci 96:165-75. 2006
    ..However, luteal area and mean spot pixel values are better but not strong indicators of the functional status of the CL in cyclic ewes...
  17. ncbi request reprint Effects of treatment with LH or FSH from 4 to 8 weeks of age on the attainment of puberty in bull calves
    E T Bagu
    Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, Canada S7N 5B4
    Theriogenology 62:861-73. 2004
    ..We concluded that treatment of bull calves with bFSH from 4 to 8 weeks of age increased testicular growth (SC); hastened onset of puberty (SC > or = 28 cm); and enhanced spermatogenesis...
  18. ncbi request reprint Patterns of expression of steroidogenic enzymes during the first wave of the ovine estrous cycle as compared to the preovulatory follicle
    R Duggavathi
    Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada
    Anim Reprod Sci 91:345-52. 2006
    ....
  19. ncbi request reprint Effect of feed restriction during calfhood on serum concentrations of metabolic hormones, gonadotropins, testosterone, and on sexual development in bulls
    L F C Brito
    Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Dr, Saskatoon, Saskatchewan, Canada S7N 5B4
    Reproduction 134:171-81. 2007
    ....
  20. ncbi request reprint Antral follicle growth and endocrine changes in prepubertal cattle, sheep and goats
    N C Rawlings
    Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, 52 Campus Drive, Saskatoon, SK, Canada S7N 5B4
    Anim Reprod Sci 78:259-70. 2003
    ....
  21. ncbi request reprint Luteogenesis in cyclic ewes: echotextural, histological, and functional correlates
    R Duggavathi
    Department of Veterinary Biomedical Sciences, WCVM, University of Saskatchewan, Saskatoon, Saskatchewan, Canada S7N 5B4
    Biol Reprod 69:634-9. 2003
    ..Echotexture of the CL was closely associated with its morphological and functional characteristics; image analysis holds promise for noninvasive monitoring of CL differentiation and growth...
  22. doi request reprint Postnatal changes in testicular concentrations of transforming growth factors-alpha and-beta 1, 2 and 3 and serum concentrations of insulin like growth factor I in bulls
    E T Bagu
    Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada
    Reprod Domest Anim 45:348-53. 2010
    ..05). We concluded that TGF-alpha and TGF-beta 1, 2 and 3 are present in the testis of the bull calf, and changes in concentrations with age suggest a functional role in the development of the testis...
  23. doi request reprint Post-natal changes in testicular concentrations of interleukin-1 alpha and beta and interleukin-6 during sexual maturation in bulls
    E T Bagu
    Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, SK, Canada
    Reprod Domest Anim 45:336-41. 2010
    ..These findings suggest a functional role for interleukins in testicular development in the bull...
  24. ncbi request reprint Ultrasound and endocrine evaluation of the ovarian response to PGF2alpha given at different stages of the luteal phase in ewes
    D M W Barrett
    Department of Veterinary Biomedical Sciences Western College of Veterinary Medicine, University of Saskatchewan, Saskatoon, Canada
    Theriogenology 58:1409-24. 2002
    ....
  25. ncbi request reprint Effects of treatment with GnRH from 4 to 8 weeks of age on the attainment of sexual maturity in bull calves
    S Madgwick
    Department of Agriculture, University of Newcastle upon Tyne, Newcastle upon Tyne NE1 7RU, UK
    Anim Reprod Sci 104:177-88. 2008
    ..This may provide the basis for a simple regimen to hasten sexual development in the bull calf...
  26. ncbi request reprint Ovarian responses, hormonal profiles and embryo yields in anoestrous ewes superovulated with Folltropin-V after pretreatment with medroxyprogesterone acetate-releasing vaginal sponges and a single dose of oestradiol-17beta
    P M Bartlewski
    Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada
    Reprod Domest Anim 43:299-307. 2008
    ..In conclusion, the MAP-E(2)-17beta pretreatment significantly reduced the variability in ovarian responses and embryo yields, without affecting the embryo production in superovulated anoestrous ewes...
  27. ncbi request reprint Ultrasonographic characteristics of ovulatory follicles and associated endocrine changes in cyclic ewes treated with medroxyprogesterone acetate (MAP)-releasing intravaginal sponges and equine chorionic gonadotropin (eCG)
    X Liu
    Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, Canada
    Reprod Domest Anim 42:393-401. 2007
    ....
  28. ncbi request reprint Ultrasonographic image attributes of non-ovulatory follicles and follicles with different luteal outcomes in gonadotropin-releasing hormone (GnRH)-treated anestrous ewes
    X Liu
    Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, Ont N1G 2W1, Canada
    Theriogenology 67:957-69. 2007
    ..In conclusion, ovarian antral follicles with different outcomes after GnRH treatment (in seasonally anestrous ewes) had distinctive ultrasonographic characteristics...
  29. ncbi request reprint Ultrasonographic study of the effects of the corpus luteum on antral follicular development in unilaterally ovulating western white-faced ewes
    P M Bartlewski
    Department of Agriculture, University of Newcastle, King George VI Building, Newcastle upon Tyne, NE1 7RU, Newcastle, UK
    Anim Reprod Sci 65:231-44. 2001
    ..In the transition to anoestrus and during mid-anoestrus, the presence of the CL in an ovary appeared to maintain follicle development to ovulatory sizes and to increase the rate of turnover of large antral follicles, respectively...