@conference {40998,
	title = {Some Effects of Using Progesterone and Gonadotrophin Releasing Hormone on the Reproductive Performance of Inseminated Cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {58},
	year = {1998},
	month = {Jan},
	pages = {92-94},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {The administration of progesterone (P4) within 3 days following insemination can reduce pregnancy rates. In contrast, an injection of gonadotrophin releasing hormone (GnRH) at about 12 or 13 days after insemination can increase them by around 10\%. This field trial tested the hypothesis that the negative effects reported for the P4 treatment on fertility could be eliminated by strategically injecting GnRH to convert the two ovarian follicle waves per cycle created by using P4, into three wave ones, with increased fertility. A total of 830 cows in 13 dairy herds received comparative treatments involving: (i) the insertion of a P4 intravaginal device 2 or 3 days after first insemination (1st insem.) for 10 days, with an injection of 10 mg of GnRH at device removal (P4 + GnRH); (ii) the same GnRH treatment but without P4 pre-treatment (GnRH); and, (iii) no post-insemination intervention (Control). Pregnancy status and conception date were confirmed by rectal palpation of uterine contents Calving data were recovered from 10 herds to monitor gestation length, dystocia and calf birth weight. The conception rates to 1st insem. were highest for the 255 cows treated with GnRH (64\%; p = 0.05), but similar in the other two groups of 273 and 302 cows (57\%). Second insemination results were not affected by the treatments; neither were final pregnancy rates. Birth weights were higher for bull than heifer calves (36.9 vs 33.0kg; p<0.01), but were not affected by treatment. The results of this trial showed that the P4 + GnRH treatment did have normal fertility and that GnRH injected 12 or 13 days after first insemination could increase conception rates. },
	issn = {1176-5283},
	author = {Taufa VK and Macmillan KL and Day AM and Ashcroft MJ and Morgan S}
}
@conference {40945,
	title = {The responses of lactating cows treated for anoestrus to an oestradiol capsule or an oestradiol injection.},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {57},
	year = {1997},
	month = {Jan},
	pages = {241},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	abstract = {Postpartum anovulatory anoestrus is a mjor form of infertility among cows in dairy herds inNew Zealand. The currently recommended treatment involves a 5-day prim-ing with progersterone (P4) released from a CIDR TM device (InterAg, NZ), with a 10 mg gelatin of oestradiol benzoate (ODB) and 1 g lactose capsule (CIDR TM; InterAg, NZ) placed in the grooved surface of the device preceding device insertion, and an injection of ODB (CIDIROLTM ; InterAg, NZ) given intramuscularly at 24 to 48h following device removal.},
	issn = {1176-5283},
	author = {Taufa VK and Macmillan KL and Nation DP and Day AM and Ashcroft MJ}
}
