Administration of GnRH at estrus influences pregnancy rates, serum concentrations of LH, FSH, estradiol-17 beta, pregnancy-specific protein B, and progesterone, proportion of luteal cell types, and in vitro production of progesterone in dairy cows

Mo, Mee; Js, Stevenson; Bm, Alexander; Rg, Sasser

doi:10.2527/1993.711185x

Cited by 51 publications

(31 citation statements)

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“…Surprisingly, a large proportion (30 to 40 per cent) of the animals in the control groups had also received treatments for previous fertility-related conditions, possibly reflecting the pressure that modern dairy cows are under. Survival analysis in this study did not reveal any positive effect of fertility treatment, despite the number of studies supporting the efficacy of various drugs to treat repeat breeders (Stevenson and others 1990, Mee and others 1993, Villarroel and others 2004, Répási and others 2005, Szenci and others 2006). Indeed, treated repeat breeder animals took a considerably longer time after calving to establish a pregnancy compared with untreated animals.…”

Section: Discussioncontrasting

confidence: 64%

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Predisposition to repeat breeding in UK cattle and success of artificial insemination alone or in combination with embryo transfer

Canu

Boland²,

Lloyd³

et al. 2010

Veterinary Record

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To investigate whether there was a subpopulation of repeat breeders (cows or heifers that returned to oestrus after three inseminations) that were less fertile after a fourth artificial insemination (AI) with or without additional embryo transfer, and to estimate the efficacy of AI plus embryo transfer to overcome repeat breeding problems, a two-part investigation was carried out. Part 1 involved 85 repeat breeders and 85 controls subjected to AI alone. In part 2, 128 repeat breeders received AI on day 0 plus an embryo transfer seven days later, while controls received embryo transfer alone on day 7. In repeat breeders, the interval between calving and pregnancy was 80 days longer than in the controls (P=0.01), irrespective of previous fertility treatment which had mainly focused on the ovaries. The incidence of dystocia was similar in repeat breeders and in controls, but repeat breeders had a higher previous incidence of moderate uterine infection compared with controls (P=0.04). In repeat breeder cows, pregnancy rates for AI alone were 30 per cent after the fourth AI (controls: 45 to 64 per cent after one to three inseminations) compared with 52.6 per cent after a fourth AI with embryo transfer (controls with embryo transfer alone: 49 per cent). Successful pregnancies after a fourth AI plus embryo transfer produced a 6.25 per cent incidence of twins.

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Section: Discussioncontrasting

confidence: 64%

“…There have been many studies on pharmacological treatment for repeat breeders but success rates have been poor (Stevenson and others 1990, Mee and others 1993, Villarroel and others 2004, Répási and others 2005). Therefore a remedy involving artificial reproductive technologies may be more appropriate.…”

mentioning

confidence: 99%

Predisposition to repeat breeding in UK cattle and success of artificial insemination alone or in combination with embryo transfer

Canu

Boland²,

Lloyd³

et al. 2010

Veterinary Record

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“…Echternkamp (1978) administered gonadorelin to puerperal anestrous beef cows and detected a significant dose response in AUC. Also Mee et al. (1993) determined LH response to various doses of gonadorelin given immediately after artificial insemination to dairy cows, approximately 12–20 h after the spontaneous LH surge.…”

Section: Discussionmentioning

confidence: 99%

Effect of GnRH Dose on Occurrence of Short Oestrous Cycles and LH Response in Cyclic Dairy Heifers

Rantala

Peltoniemi

Katila

et al. 2009

Reprod Domestic Animals

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Prostaglandin F(2 alpha) (PGF(2 alpha)) and GnRH treatments given 24 h apart have been shown to result in short oestrous cycles (8-12 days) in some cows and heifers. The differences in responses may depend on the dose of GnRH. Therefore, the effect of the dose of GnRH on occurrence of short cycles and LH response was studied here. Oestrus was induced with dexcloprostenol (0.15 mg) in two groups of Ayrshire heifers. A second luteolysis was induced similarly on day 7 after ovulation; 24 h after PGF(2 alpha) treatment, the heifers were administered either a high (0.5 mg, n = 15, group T500) or low (0.1 mg, n = 10, group T100) dose of gonadorelin. Blood samples for progesterone analyses were collected daily from the second PGF(2 alpha) administration to the second ovulation after the PGF(2 alpha) injection. Beginning 24 h after the GnRH treatment, ovaries were examined by transrectal ultrasonography every 6 h until ovulation, and daily between day 4 and the next ovulation. Five heifers from both groups were sampled for LH analyses via a jugular catheter every 30 min from 1 h before to 6 h after the GnRH administration. Short oestrous cycles were detected in 7 of 10 cases in group T100 and in 12 of 15 cases in group T500. No significant differences in LH responses were detected between the groups. In group T500, the rise in LH concentration tended to be somewhat slower than in group T100. The dose of GnRH (0.1 vs 0.5 mg) did not affect the occurrence of short oestrous cycles and LH response.

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“…Treatment with buserelin increases the number of LLC and the volume of the CL present at the time of treatment (Twagiramungu et al, 1995a). Likewise, Mee et al (1993) reported an increase of the number of LLC in 10-d-old CL when Cystorelin was administered at estrus. Treatment of ewes with LH or hCG increases the number of LLC and decreases that of SLC (Niswender et al, 1985;Farin et al, 1988).…”

Section: Functional and Morphological Changes Of The Corpus Luteummentioning

confidence: 93%

Synchronization of ovarian follicular waves with a gonadotropin-releasing hormone agonist to increase the precision of estrus in cattle: a review.

Twagiramungu

Guilbault

Dufour

1995

Journal of Animal Science

224

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Treatment with GnRH and PGF2 alpha is a practical method for controlling ovarian follicular and luteal functions and increasing the precision of estrus synchronization in cyclic and acyclic postpartum cows and heifers. This method reduces considerably the period of time needed for estrus detection; it synchronizes the estrous cycle of 70 to 80% of the cyclic cows to within a 4-d interval without any detrimental effect on the fertility rate (65 to 85%). Moreover, resumption of ovarian activity and normal fertility in acyclic cows in favored. Administration of GnRH eliminates the large follicles by ovulation or atresia and induces emergence of a new follicular wave within 3 to 4 d after treatment at any stage of the estrous cycle, but it limits further growth of these emerging follicles by increasing atresia. The precision of estrus and the unaltered fertility rate is due to the synchronized selection of a new larger growing follicle, which becomes the ovulatory follicle after PGF(2 alpha)-induced luteolysis 6 d after GnRH treatment. Also, fixed-time AI programs without the need for estrus detection may be possible using a second injection of GnRH in a GnRH-PGF(2 alpha)-GnRH protocol to ovulate the selected follicle at a precise time. We describe a physiological model to explain how the precision of estrus is improved following PGF(2 alpha)-induced luteolysis, via the effect of pretreatment with GnRH on follicular development and luteal functions in cattle. Application of this model to the development of reliable methods of fixed-time insemination is also explored.

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Administration of GnRH at estrus influences pregnancy rates, serum concentrations of LH, FSH, estradiol-17 beta, pregnancy-specific protein B, and progesterone, proportion of luteal cell types, and in vitro production of progesterone in dairy cows

Cited by 51 publications

References 0 publications

Predisposition to repeat breeding in UK cattle and success of artificial insemination alone or in combination with embryo transfer

Predisposition to repeat breeding in UK cattle and success of artificial insemination alone or in combination with embryo transfer

Effect of GnRH Dose on Occurrence of Short Oestrous Cycles and LH Response in Cyclic Dairy Heifers

Synchronization of ovarian follicular waves with a gonadotropin-releasing hormone agonist to increase the precision of estrus in cattle: a review.

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