Hormonal Responses of Dairy Cows with Ovarian Cysts to GnRH5

Cantley, T.C.; Garverick, H.A.; Bierschwal, C.J.; Martin, C; Youngquist, R.S.

doi:10.2527/jas1975.4161666x

Cited by 96 publications

(19 citation statements)

References 16 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Exogenous injection of estradiol often fails to induce an LH surge in cows with naturally occurring or induced follicular cysts [14][15][16][17][18], whereas injection of GnRH can induce the release of LH [19][20][21]. Taken together, these findings strongly suggest that an important physiological change in cystic cows is the lack of an LH surge owing to a functional abnormality in the estradiolfeedback regulation of LH secretion.…”

Section: Induction Of Follicular Cyst Formation By Perturbation Of Esmentioning

confidence: 50%

Formation of Follicular Cysts in Cattle and Therapeutic Effects of Controlled Internal Drug Release

Todoroki

Kaneko

2006

Journal of Reproduction and Development

View full text Add to dashboard Cite

Abstract. Follicular cysts in cattle result from excessive growth of the dominant follicle without ovulation and still constitute a major reproductive disorder in this species. One key hormonal characteristic of cows with follicular cysts is the lack of an LH surge, although they have increased plasma estradiol concentrations. Another is a relatively high level of pulsatile secretion of LH that promotes continued growth of the dominant follicle. These LH characteristics seem to result from a functional abnormality in the feedback regulation of LH secretion by estradiol. Treatment with controlled internal drug release devices that increase circulating progesterone levels is effective in resolving follicular cystic conditions by 1) lowering pulsatile LH secretion and 2) restoring the ability of the hypothalamo-pituitary axis to generate an LH surge in response to an increase in circulating estradiol.

show abstract

Section: Induction Of Follicular Cyst Formation By Perturbation Of Esmentioning

confidence: 50%

Formation of Follicular Cysts in Cattle and Therapeutic Effects of Controlled Internal Drug Release

Todoroki

Kaneko

2006

Journal of Reproduction and Development

View full text Add to dashboard Cite

show abstract

“…Cows with ovarian cysts are capable of releasing LH in response to GnRH (Cantley et al, 1975). Thus, a single GnRH treatment has been the standard treatment for cows with ovarian cysts (Bierschwal et al, 1975;Seguin et al, 1976;Nakao et al, 1992;Osawa et al, 1995).…”

Section: Resultsmentioning

confidence: 99%

“…Thus, a single GnRH treatment has been the standard treatment for cows with ovarian cysts (Bierschwal et al, 1975;Seguin et al, 1976;Nakao et al, 1992;Osawa et al, 1995). However, a large proportion (25% -39%) of cows with ovarian cysts treated with GnRH did not respond (Cantley et al, 1975;Nakao et al, 1992;Osawa et al, 1995;Tebble et al, 2001), probably because other follicles capable of responding to GnRH were not present (Tebble et al, 2001).…”

Section: Resultsmentioning

confidence: 99%

Preliminary Remarks in Hormonal Treatments Effects on Reproduction Period in Cows

Crivei¹,

Ruginosu²,

Borş³

et al. 2016

BUASVMCN-VM

View full text Add to dashboard Cite

The early resumption of estrous cycles following calving is important for high reproductive efficiency, but also for the cows which haven't been observed in estrus during the first 60 days after calving, the last ones having a significantly higher risk of being culled than cows that have displayed estrus .The aim of this study was to determine the effect of hormonal treatment on reproduction period in cows, and also to establish if there is any significant difference in some reproductive parameters between cows treated with hormonal medication and cows which resumed ovarian cyclicity before 60 days postpartum.This study was performed in a dairy cow's farm in North-Eastern Moldavia, over a period of 2 consecutive years, on Romanian Black Spotted cows, in order to determine hormonal treatments influence over reproduction period. Hormonal treatments used for the above mentioned diseases were represented by luteolytic agent prostaglandin F2α, one of its potent analogues (Proliz, Biotur, Romania) and by administration of exogenous gonadotrophin releasing hormone (Receptal, Intervet, Romania).We noticed that average reproduction period (52.1 days) and the other breeding intervals that were taken under study (over a two years period), presented different values for cows that have been under hormonal medication treatment, compared to those which resumed ovarian cyclicity before 60 days postpartum (52.7 days).Thus, this preliminary study supports the development of a more detailed study on several dairy cows' farms in order to investigate the answer of different types of hormonal treatments against persistent corpus luteum and cystic ovarian disease.

show abstract

“…evaluation (5). However, although LH is released in a dose-dependent manner in the cow, it is not highly sensitive (overlap exists between doses) (16,17). Furthermore, the quantity of LH released is not correlated to the efficacy of gonadorelin (18).…”

Section: Discussionmentioning

confidence: 98%

Gonadorelin-Induced Testosterone Release: A Biological Assay for Quality Assurance of Gonadorelin in Veterinary Medicine

Kesler

Summers

Peterson

et al. 1999

Drug Development and Industrial Pharmacy

View full text Add to dashboard Cite

Two experiments were conducted with bulls administered norgestomet and gonadorelin to determine if the gonadorelin-induced release of testosterone could be developed into a biological assay for quality assurance of gonadorelin. Implants containing norgestomet (0 to 36 mg) reduced the episodic release (r = -.81; P < .05) and mean concentrations of testosterone (r = -.82; P < .05). Gonadoreline-induced testosterone release increased (r = .99; P < .05) with increasing dosage of gonadorelin (up to 5 micrograms) in norgestomet-implanted bulls (36 mg). Maximal testosterone was released (> sixfold increase) with 5 to 40 micrograms of gonadorelin. In summary, the gonadorelin-induced testosterone release in bulls administered a synthetic progestin is a sensitive (0.008 microgram per kg body weight for 5 micrograms of gonadorelin) biological assay with a rapid turnaround time for the confirmation of gonadorelin potency. Based on a per-kg-body-weight basis, the norgestomet-treated bull is the most sensitive biological assay model.

show abstract

Hormonal Responses of Dairy Cows with Ovarian Cysts to GnRH5

Cited by 96 publications

References 16 publications

Formation of Follicular Cysts in Cattle and Therapeutic Effects of Controlled Internal Drug Release

Formation of Follicular Cysts in Cattle and Therapeutic Effects of Controlled Internal Drug Release

Preliminary Remarks in Hormonal Treatments Effects on Reproduction Period in Cows

Gonadorelin-Induced Testosterone Release: A Biological Assay for Quality Assurance of Gonadorelin in Veterinary Medicine

Contact Info

Product

Resources

About