@conference {41989,
	title = {Restricted postpartum feeding in grazing dairy heifers decreases milk production but does not lengthen oestrous interval},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {67},
	year = {2007},
	month = {Jan},
	pages = {255-260},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Wanaka},
	abstract = {The aim of this study was to determine the effects of pasture allowance postpartum on the initiation of ovarian activity, metabolite and hormonal secretion, and milk production. After calving, thirty six HolsteinFriesian heifers (BCS 5.0) received either unrestricted pasture allowance (UNR; n=18) or restricted (RES; 73\% dry matter intake of the unrestricted group;n=18) pasture allowance. The LW was lower (P < 0.05) for the RES group than the UNR group. Body condition score of all heifers decreased after calving in both groups. The mean time to ovulation was similar for UNR 50.0 and RES 50.3 sed. 8.2 days after individual calving date. The daily average from week 2 for milksolids, protein and lactose yield was lower (P < 0.05) in the RES group. Plasma concentrations of insulin were lower (P = 0.0085) in the RES group when compared to the UNR group. Glucose concentrations was lower (P = 0.016) in the RES group. Plasma concentration of NEFA was greater (P = 0.001) in the RES group. There was an interaction with treatment differences decreasing by week 11 and 12 for glucose (P =0.001) and NEFA (P =0.006). Plasma concentrations of leptin (P = 0.013) and IGF-I (P = 0.026) were lower in the RES. No differences, associated with postpartum nutrition, were found for plasma GH. Restricted feeding postpartum had no effect on days to first postpartum ovulation but decreased liveweight, milk production and affected some metabolic hormones during postpartum.},
	issn = {1176-5283},
	author = {Chagas LM and Gore PJS and MacDonald KA and Blache D}
}
@conference {41670,
	title = {Diet or strain: Effects on postpartum anovulatory interval in dairy cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {66},
	year = {2006},
	month = {Jan},
	pages = {339-343},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Napier},
	abstract = {Changes in cow genetics and systems of farming have had large effects on the reproductive performance of dairy cows. The objective of this study was to determine if grain supplementation modified the previously identified effects of Holstein-Friesian (HF) strain on the postpartum anoestrus interval (PPAI). Thirty multiparous Overseas (OS) HF and 30 New Zealand-HF cows from a 1990s strain (NZ) were offered unrestricted access to fresh pasture and randomly allocated to three levels of a maize and barley-based concentrate supplementation (0, 3 or 6 kg DM/day). Postpartum anovulatory interval (PPAI) was not significantly affected by either strain or diet, and there was no significant strain x diet interaction. Results suggest that the nutritional requirements necessary for multiparous NZ or OS HF cows to resume oestrous cycles before 40 days postpartum can be achieved when offered unrestricted access to high quality pasture. In this circumstance, additional concentrate feeding did not alter the length of the postpartum anoestrous interval. },
	issn = {1176-5283},
	author = {Chagas LM and Gore PJS and Sheahan AJ and Lee JM and Watkins KA and Aspin PW and Roche JR}
}
@conference {41282,
	title = {Postpartum anoestrous interval and metabolic changes in heifers supplemented with pasture prepartum},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {61},
	year = {2001},
	month = {Jan},
	pages = {188-191},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {The aim of this study was to determine whether supplementation with pasture from 6 weeks before calving would alter the postpartum anoestrous interval (PPAI) in heifers calving with low body condition score (BCS). Metabolic hormones and metabolites were measured during the pre- and postpartum period. Forty Friesian heifers were managed during the last five months of gestation to achieve a BCS (1-10) of 4.0 (restricted; R; n=27) or 5.0 (fully fed; FF; n=13) by 6 weeks prepartum. One group with low BCS then received pasture ad libitum until calving (restricted + fully fed; R+FF; n=12). Live weight (LW) and BCS were assessed weekly. Blood samples were collected weekly from 10 weeks prepartum to 10 weeks postpartum to measure glucose, urea, non-esterified fatty acids (NEFA), betahydroxybutyrate (BOH) and cholesterol content. The patterns of metabolites measured differed between groups at different times, future work to investigate the relationship these profiles and PPAI would be of value. The percentage of cows cycling as measured by an elevated milk progesterone concentration was 69\%, 75\% and 8\% for FF, R+FF and R groups, respectively. Fully feeding heifers, with low condition score, 6 weeks before calving decreased PPAI when compared to heifers receiving restricted feeding. },
	issn = {1176-5283},
	author = {Chagas LM and Morgan SR and Gore PJS and Clark BA and Verkerk GA}
}
