@conference {42049,
	title = {Effect of genotype and concentrate supplementation on dairy product mix and the value of milk produced by grazing dairy cows during an extended lactation},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {68},
	year = {2008},
	month = {Jan},
	pages = {79-83},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Brisbane, Australia},
	abstract = {Dairy product mix and milk value were investigated in Holstein-Friesian cows of New Zealand or overseas origin that grazed pasture and were supplemented with 0, 3 or 6 kg DM concentrate/cow/day during a 600-day extended lactation. A dairy product supply chain model was used to predict relative changes in dairy product mix and milk value during the "extended period" (300 to 600 days in milk) compared with the "normal period" (0 to 300 days in milk). Cow genotype and level of concentrate supplement affected dairy product yields, with little consistency of effect between "normal" and "extended" periods. Milk produced during the "extended period" resulted in more cheese, butter, butter milk powder, casein, and whey protein concentrate, but less whole milk powder, skim milk powder and whey milk powder compared to the "normal period". The overseas strain and those cows receiving higher levels of concentrates had less of a decline in whole milk powder yields associated with the "extended period". Milk value ($/L), was predicted to be 20.8\% higher during the "extended period" compared with the "normal period". These results indicate that extended lactations may improve the dairy product mix and milk value following processing. },
	issn = {1176-5283},
	author = {Turner S-A and Phyn CVC and Kolver ES and Aspin PW and Lopez-Villalobos N}
}
@conference {42055,
	title = {Effect of genotype and diet on feed conversion efficiency of dairy cows during a 600-day extended lactation},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {68},
	year = {2008},
	month = {Jan},
	pages = {100-104},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Brisbane, Australia},
	abstract = {This study investigated the effect of genotype and diet on the gross feed conversion efficiency (FCE) of cows milked for 600-day extended lactations (24-month season) compared with 300-day lactations (12-month season). North American (NA) and New Zealand (NZ) Holstein-Friesians (HF) grazed pasture and were supplemented with either 0, 3 or 6 kg DM concentrate/cow/day. In a normal 12-month season, gross FCE was greater for NZ HF compared with NA HF cows when fed 0 or 3 kg DM concentrate (96 and 104 vs. 90 and 99 kg milksolids (MS)/t dry matter intake (DMI), respectively), but similar when fed 6 kg DM (101 kg MS/t DMI). However, during an extended 24-month season, NZ HF cows had a lower gross FCE than NA HF when fed 6 kg DM concentrate (86 vs. 99 kg MS/t DMI, respectively) and similar FCE when fed 0 or 3 kg DM (85 and 94 vs. 86 and 99 kg MS/t DMI, respectively). Regardless of diet, gross FCE in an extended lactation was 98\% of that obtained in a normal season for NA HF cows, but only 88\% for NZ HF, indicating that NA HF are better suited to converting feed into high MS production in extended lactations. },
	issn = {1176-5283},
	author = {Phyn CVC and Clark C and Aspin PW and Kolver ES}
}
@conference {41749,
	title = {Production and physiological indicators to select cows suitable for extended lactations},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {67},
	year = {2007},
	month = {Jan},
	pages = {315-319},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Wanaka},
	abstract = {Individual cows vary in their ability to maintain milk production for an extended lactation. Identifying production and physiological markers to indicate cows suitable for extended lactations would allow dairy farmers to make early decisions to withhold mating of individual cows or to continue milking specific nonpregnant cows through the winter months. Fifty-six genetically divergent overseas and New Zealand Holstein Friesians were allocated to three pasture-based dietary treatments (0, 3 and 6 kg concentrate DM/cow/d) and mating was withheld to target a 670-d lactation. Within each treatment there was little correlation between animal evaluation index values and milksolids (MS) production during the extended lactation period (>296 days in milk; DIM). There was a positive correlation between MS yield from the initial normal season (<296 DIM) and extended lactation MS production; and a negative correlation between body condition score (BCS) at theoretical dry off date (~296 DIM) and extended lactation MS yield. Plasma hormone and metabolite data from wk 1-10 postpartum demonstrated a positive association between nonesterified fatty acid levels and extended lactation MS production, whereas glucose,insulin, and insulin like growth factor-1 were negatively associated with extended lactation MS production. Overall, data indicate that the animal evaluation index is not a good indicator of animals suitable for extended lactation, however normal season milk production, early lactation plasmahormone and metabolite and late lactation BCS data may be useful to identify animals that will undergo a successful extended lactation.},
	issn = {1176-5283},
	author = {Kay JK and Aspin PW and Phyn CVC and Roche JR and Kolver ES}
}
@conference {41735,
	title = {Supplemental fumarate has little effect on the detailed composition of bovine milk during early lactation},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {67},
	year = {2007},
	month = {Jan},
	pages = {242-247},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Wanaka},
	abstract = {Future farming practices need to be assessed by the dairy industry for any impacts they may have on the detailed composition and processability of milk. These impacts may change the milk price a farmer receives and the milk processability,product range and product quality. The use of sodium fumarate (an organic acid) to reduce methane production from dairy cows has previously been reported. This experiment investigated the effect of intra-ruminal infusions of sodium fumarate on the detailed composition of milk from dairy cows. Fumarate (5\% of daily dry matter intake) was infused into 8 lactating cows while 8 cows received infusions of water as a control. Milksamples were collected during a covariate period, then again following a 16-day treatment period, of which cows were housed indoors for the last 9 days. Gross composition of milk and other production parameters have been presented previously. Milk yield, fat and protein were not affected but lactose concentrations were significantly higher in the milk of cows receiving the fumarate. In the current study, none of the individual casein proteinsmeasured showed an effect of treatment. Of the whey proteins examined, concentrations of α-lactalbumin (α-La) were higher (1.07 vs. 0.98 mg/mL; sed 0.038; P < 0.05) and bovine serum albumin (BSA) concentrations were lower (214.6 vs. 251.0 mg/L; sed 15.1; P < 0.05) in the milk of cows receiving fumarate. None of the individual fatty acids or minerals examined showed a treatment effect. The addition of sodium fumarate to the diet of dairy cows in early lactation does not have a major influence on the composition of milk, suggesting that the product could be used with minimal impact on milk composition and product quality at this early stage of lactation.},
	issn = {1176-5283},
	author = {Turner S-A and Aspin PW and Kolver ES}
}
@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 {41652,
	title = {Effect of genotype and diet on milksolids production, body condition, and reproduction of cows milked continuously for 600 days},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {66},
	year = {2006},
	month = {Jan},
	pages = {245-251},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Napier},
	abstract = {Milking cows for two consecutive years, with calving and mating occurring every second year, may exploit the superior lactation persistency of high yielding cows while improving reproductive performance. This study tested the feasibility of extended lactations in pastoral systems using divergent dairy cow genotypes (New Zealand [NZ] or Overseas [OS] Holstein-Friesian [HF]) and levels of nutrition (0, 3, or 6 kg concentrate DM/cow/day). Cows calved on 28 July 2003 and remaining cows were dried off by 6 May 2005. Of the 56 cows enrolled, 93\% were milking at 500 days in milk (DIM) and 18\% were milking at 650 DIM. Dietary treatments did not affect DIM (605 {\textpm} 8.3; Mean {\textpm} SEM), but there was a trend (P=0.09) for OS HF to have longer lactations than NZ HF. Genotype x diet interactions were detected for the total yield of milk and milksolids per cow, and as a percentage of liveweight. Differences between genotypes were greatest at the highest level of supplementation. Compared to NZ HF, OS HF produced 35\% more milk, 24\% more milk fat, 25\% more milk protein, and at drying off had 1.9 units less body condition. Annualised milksolids production from NZ HF was 79\% of a normal season{\textquoteright}s production, compared to OS HF that produced 94\%. Compared to NZ cows, OS cows had a similar 21-day submission rate (85\%), a lower 42-day pregnancy rate (56\% vs. 79\%), and a higher final empty rate (30 vs. 3\%) when mated at 451 days after calving. These results indicate that productive extended lactations up to 650 days are biologically possible on a range of pasture diets, and with appropriate cow genetics and feed management may ameliorate poor reproductive performance in high yielding dairy cows without sacrificing milksolids production. },
	issn = {1176-5283},
	author = {Kolver ES and Roche JR and Burke CR and Aspin PW}
}
@conference {41921,
	title = {A nutrient-signalling effect of grain feeding on postpartum anovulatory intervals in mature dairy cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {66},
	year = {2006},
	month = {Jan},
	pages = {334-338},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Napier},
	abstract = {Our previous study with mature dairy cows found that increased pasture intakes in early lactation resulted in more milk being produced but with no change in postpartum anovulatory intervals (PPAI). The present study used a 2 x 2 factorial to determine PPAI in 68 cows with pre- and post-calving diets that were iso-energetic, but varying in the ratio of structural to non-structural carbohydrate. At 36 {\textpm} 8.7 days prepartum, cows were assigned iso-energetic diets (114 MJ ME/cow/day) of either pasture/pasture silage (n=34) or the same diet supplemented with 3 kg DM/cow/d barley-maize concentrate (n=34). After calving, cows within each prepartum diet were assigned iso-energetic diets (179 MJ ME/cow/d) of either pasture/pasture silage (n=34) or the same diet supplemented with 5 kg DM/cow/d concentrate (n=34). Postpartum grain feeding reduced (P < 0.05) PPAI (28.4 {\textpm} 1.8 day) compared to the pasture/pasture silage only diet (36.4 {\textpm} 2.5 day). Prepartum diet did not affect PPAI. Body condition score was inversely related to PPAI at all time points (P < 0.05), but explained little (5-12\%) of the variability in PPAI. Significant relationships to PPAI were also found for blood non-esterified fatty acids, urea and magnesium, but again, r2-values were <= 0.1. None of the milk characteristics measured were significantly related to PPAI. This study supports the premise that discrete or specific nutritional cues unrelated to general energy status can favourably target physiological functions in reproductive tissues at the brain and/or ovarian levels. },
	issn = {1176-5283},
	author = {Burke CR and Roche JR and Aspin PW and Lee JM}
}
@conference {41935,
	title = {Plasma insulin, growth hormone, and IGF-1 concentrations of Holstein - Friesian cows of divergent genotype offered varying levels of concentrate in early lactation},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {66},
	year = {2006},
	month = {Jan},
	pages = {403-408},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Napier},
	abstract = {This study of insulin and key hormones of the somatotropic axis was made to help explain the milksolids and body condition responses obtained from cows of divergent Holstein-Friesian (HF) genotypes fed differing levels of concentrate. Weekly plasma concentrations of insulin, insulin-like growth factor-1 (IGF-1) and growth hormone (GH) were measured from 57 North American (overseas; OS) and New Zealand (NZ) cows in the first 10 weeks of lactation during the 2002/03 and 2003/04 seasons. Cows of similar breeding worth grazed at a high pasture allowance and were individually fed 0, 3 or 6 kg concentrate DM/cow/day. Compared to NZ HF, OS HF had similar insulin concentrations, lower IGF-1 concentrations, and higher GH concentrations. Feeding 3 or 6 kg concentrate DM/day increased insulin and IGF-1 concentrations to a similar extent, with GH concentrations being reduced at the highest level of supplementation. These results are consistent with the previously reported greater loss of body condition in OS HF, and suggest genotype differences in insulin resistance and rate of recoupling of the somatotropic axis after calving. The reported gain in body condition when concentrates were fed is probably a result of the increased insulin production and a positive effect on liver GH receptor 1A, with the consequent increase in IGF-1 and reduction in GH. Diet only began to affect GH concentrations, and therefore body condition loss, after approximately week 4-6 of lactation. These results have implications for feed management and breeding. },
	issn = {1176-5283},
	author = {Kolver ES and Roche JR and Aspin PW}
}
@conference {41650,
	title = {Prevalence of mastitis for cows of different genotypes milked for two consecutive seasons},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {66},
	year = {2006},
	month = {Jan},
	pages = {236-240},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Napier},
	abstract = {Extending the calving interval from the traditional 12-month to a 24-month calving interval has been suggested as a practical solution for maximizing lactation yield per calving. Somatic cell count (SCC) and the incidence of mastitis were examined in New Zealand (NZ) and overseas (OS) Holstein-Friesian cows fed on pasture alone or supplemented with 3 or 6 kg DM maize/barley concentrates/cow/day during an extended lactation of up to 21 months. Average cow SCC was three-fold higher (P<0.001) in the extended or second season of the lactation compared with the first season, with NZ cows having a slightly higher SCC (P<0.01) in the second season compared to OS cows (191,000 and 115,000 cells/ml respectively). The SCC elevations occurred regardless of infection status of the udder. Although OS cows tended to have twice as many cases of clinical mastitis (P=0.01) in the first season compared to the NZ cows, affecting 59\% and 27\% of cows respectively, there was no difference in infection status between genotypes in the second season (20\% and 18\% respectively). Results showed that although cows experienced less mastitis during the second spring of the lactation, the average cow SCC was higher during the extended part of the lactation. },
	issn = {1176-5283},
	author = {Lacy-Hulbert SJ and Summers EL and Williamson JH and Aspin PW and Kolver ES}
}
@conference {41684,
	title = {Supplemental fumarate did not influence milksolids or methane production from dairy cows fed high quality pasture},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {66},
	year = {2006},
	month = {Jan},
	pages = {409-415},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Napier},
	abstract = {This experiment tested the hypothesis that methane emissions from dairy cows would be reduced, and milk production increased, when sodium fumarate was added to a diet of fresh pasture at a rate of 5\% of dry matter (DM) intake. Sixteen ruminally fistulated dairy cows (100 {\textpm} 20.7 days in milk; 548 {\textpm} 47.8 kg liveweight; mean {\textpm} SD) received either a control (water) or fumarate treatment (10.3 {\textpm} 1.18 L/cow/day of solution providing 931 {\textpm} 126 g sodium fumarate/cow/day) over a 7-day adjustment period while grazing ryegrass pasture, followed by an 8-day experimental period fed pasture in metabolism stalls. During the experimental period cows on both treatments consumed 18.8 {\textpm} 1.83 kg DM/day, produced 1.81 {\textpm} 0.25 kg milksolids/day, and emitted 350 {\textpm} 44.9 g methane/day (5.9 {\textpm} 0.71\% of gross energy). Total tract DM digestibility was high (78.8 {\textpm} 0.84\%), and ruminal pH was 6.10 {\textpm} 0.15. Fumarate supplementation did not change ruminal fermentation, in vivo digestibility, methane emissions, milk production or composition, or selected plasma metabolites. The opportunity for reducing methane emissions from dairy cows by supplementing with fumarate or breeding high fumarate grasses may be limited for diets of high quality pasture. The limited reports of in vivo response to supplemental fumarate suggest that mitigation opportunities may be greater for pasture diets of low digestibility. },
	issn = {1176-5283},
	author = {Kolver ES and Aspin PW}
}
@conference {41937,
	title = {Supplementation with concentrates either pre- or post-partum does not affect milk production when diets are iso-energetic},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {66},
	year = {2006},
	month = {Jan},
	pages = {416-422},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Napier},
	abstract = {Dairy cow glucose requirements increase dramatically during the weeks preceding calving, suggesting that supplements that increase glucose supply (rapidly fermentable carbohydrates) would reduce precalving mobilisation of body tissue and improve subsequent milk production. Sixty-eight multiparous dairy cows were randomly allocated to one of two diets for 36 {\textpm} 8.7 days precalving. All cows were fed pasture and pasture-silage precalving, with one group also receiving 3kg DM of a barley-maize concentrate. Precalving diets were iso-energetic (114 MJ/cow/day). At calving, cows within each precalving feeding treatments were randomly allocated to two dietary treatments for 35 days in a 2x2 factorial arrangement. Postcalving, all cows received pasture and pasture silage with one group also receiving 5.0 kg DM of a barley-maize concentrate. Postcalving diets were also iso-energetic (179 MJ/cow/day). Milk yield and composition, and liveweight (LW) and body condition score (BCS) were assessed weekly for five weeks. Blood was sampled on day -21, -14, -7, 0, 1, 2, 3, 4, 7, 14, 21, 28 and 35 relative to calving, and plasma samples were analysed for indicators of energy status. Average milksolids yield (1.9 kg/cow/d) during the five weeks postcalving was not affected by either pre- or postcalving concentrate supplementation, although protein to fat ratio was higher in supplemented cows. Similarly, concentrate supplementation pre- or postcalving did not affect either LW or BCS change before or after calving. Cows receiving concentrates precalving had higher (P<0.001) plasma non-esterified fatty acid (NEFA) concentrations, but otherwise were not different to those receiving an equivalent energy intake from pasture and pasture silage. Postcalving concentrate supplementation increased (P<0.01) plasma glucose and NEFA and decreased (P<0.001) plasma B-OH butyrate. Results suggests little effect on milk production by replacing energy from structural carbohydrates in high quality pasture with energy from non-structural carbohydrate during the transition period. },
	issn = {1176-5283},
	author = {Roche JR and Lee JM and Aspin PW and Sheahan AJ and Burke CR and Kolver ES and Sugar B and Napper AR}
}
@conference {41571,
	title = {Effect of pre- and postpartum pasture feeding intakes on postpartum anoestrous intervals in dairy cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {65},
	year = {2005},
	month = {Jan},
	pages = {221-224},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {Extended postpartum anoestrous intervals (PPAI) are the predominant source of infertility on New Zealand dairy farms. A 2 x 2 factorial design was used to investigate pre- and postpartum pasture feeding levels on PPAI. Sixty-eight multiparous Holstein-Friesian dairy cows due to calve in the first three weeks of the calving period were randomly assigned to a high (11.9 kg DM/cow/day) or low (4.8 kg DM/cow/day) pasture feeding intake for 29 {\textpm} 7.7 days pre partum. After calving, cows within each prepartum feeding level were assigned to a high (13.5 kg DM/cow/day) or low (8.6 kg DM/cow/day) pasture feeding intake for 35 days. At 35 days post partum, cows were grazed as a single group with pasture silage supplementation. Concentrations of progesterone were determined in milk samples collected on Mondays and Thursdays until cows were confirmed to have resumed oestrous cycles or until one week before planned start of mating. High intakes pre-calving increased (P < 0.05) the proportion of cows cycling by the third week postpartum (38 {\textpm} 8\%) compared with a low pre-calving intake (13 {\textpm} 6\%). There was a tendency (P = 0.07) for a reduced mean PPAI in the high (29.7 {\textpm} 2.6 days) versus low (33.4 {\textpm} 2.3 days) pre-calving intake treatments, among cows that initiated oestrous cycles during the experimental period. Post-calving intake did not affect PPAI (P = 0.4), nor was an interaction detected. Body condition score (BCS) at all time points in this study, including before treatments were initiated, was negatively correlated with PPAI (P < 0.05). In contrast, PPAI was not associated (P > 0.1) with changes in BCS during the pre- or post-calving periods, or with milk production characteristics. In this study, resumption of oestrous cycling post partum was strongly linked to pre-existing differences in BCS, and modified by pre-calving pasture intake, but not influenced by feeding intakes or milk production characteristics in early lactation.
KEYWORDS: anoestrus; nutrition; dairy cow. },
	issn = {1176-5283},
	author = {Burke CR and Roche JR and Aspin PW and Lee JM and Taufa VK}
}
@conference {41570,
	title = {Effects of feeding level for four weeks precalving on milk production is small and dependent on level of feeding in early lactation},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {65},
	year = {2005},
	month = {Jan},
	pages = {215-220},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {The aim was to quantify the relationship between pre- and postcalving level of feeding and their effect on milk production. Sixty-eight multiparous dairy cows were randomly allocated to two levels of pasture feeding (Low and High; 4.8 and 11.9 kg DM/day) for 29 {\textpm} 7.7 days precalving. At calving, cows were randomly allocated (within precalving levels) to two levels of pasture feeding (Low and High; 8.6 and 13.5 kg DM/day) for 35 days postcalving. Daily milk yields were recorded and fat, protein and lactose concentrations determined on 2 days each week for 5 weeks postcalving, and once weekly for an additional 10 weeks post treatment. Body condition score (BCS) at calving was 4.2 and 4.7 for precalving Low and High treatment groups, respectively. Precalving restriction reduced milk fat production by 8.4\% during the first five weeks postcalving, but these differences were not evident subsequently. Postcalving feed restriction reduced yields of milk, fat and protein by 25, 21 and 28\%, respectively, during the first five weeks postcalving. Decreased (P < 0.05) yields of milk, fat and protein (12, 10 and 9\%, respectively) were also evident for ten weeks after the feed restriction finished. There was a trend towards a treatment interaction (P = 0.13) in milksolids (MS) production during the first five weeks of lactation between pre- and postcalving level of feeding. High- High cows produced 7.1 kg more MS than Low-High cows, but there was no effect of precalving level of feeding in cows that were restricted postcalving. Results confirm that level of feeding postcalving influences the milk production effect of precalving feeding. Nevertheless the effect of precalving energy intake on postcalving milk production is small.
KEYWORDS: transition cow; pasture; dry matter intake. },
	issn = {1176-5283},
	author = {Roche JR and Kolver ES and Lee JM and Aspin PW and Burke CR and Taylor P and Napper AR}
}
@conference {41535,
	title = {Influence of dairy cow genotype on milksolids, body condition and reproduction response to concentrate supplementation},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {65},
	year = {2005},
	month = {Jan},
	pages = {46-52},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Christchurch},
	abstract = {Responses to supplementary feeding overseas (OS) and New Zealand (NZ) Holstein-Friesian (HF) cows were investigated over two years using 57 cows receiving a high pasture allowance and 0, 3 or 6 kg concentrate DM/cow/day. Cows of similar Breeding Worth ($BW) grazed as a single herd and were individually fed a grain-based supplement. Important production genotype x diet interactions of a scaling nature were detected. Across all supplementation levels, OS cows gave a greater (P < 0.05) linear production response than NZ cows (74 vs 37 g MS/kg concentrate DM; 1.22 vs 0.67 kg milk/kg concentrate DM consumed, respectively), but gave a similar response in live weight and condition score gain during lactation per kg of concentrate DM consumed. However, because OS HF appeared to have a larger relative feed deficit than NZ HF when fed ad libitum on pasture, OS HF maintained a lower body condition score throughout lactation and produced less milksolids (as a \% of live weight). Current supplementary feeding decision rules which recommend reducing supplementary feed use when abundant pasture is available remain appropriate for high $BW NZ HF cows. However, reasonable responses to high-energy supplements will continue to be obtained from high $BW OS HF cows, even when pasture supply appears adequate to meet cow requirements. Use of indicators of relative feed deficit such as milksolids as a \% of live weight and body condition score, may be a better guide to predicting the production response to supplementation, rather than decision rules based on genotype.
KEYWORDS: Holstein-Friesian; genotype; supplements. },
	issn = {1176-5283},
	author = {Kolver ES and Roche JR and Burke CR and Aspin PW}
}
@conference {41510,
	title = {Effect of precalving feeding level on the milk production of grazing dairy cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {64},
	year = {2004},
	month = {Jan},
	pages = {227-231},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {Fifty-two multiparous dairy cows were allocated to four treatments with an apparent daily intake of 5.8, 8.9, 10.0 or 11.2 kg dry matter (DM)/cow/day of pasture for 27{\textpm}9.6 days precalving. This equated to 1.3, 2.0. 2.3 and 2.6\% of liveweight (not including the conceptus weight; LW). Following calving, all cows were fed generously on pasture. Daily milk yields were recorded postcalving and fat, protein and lactose concentrations determined on 2 days each week for 5 weeks. Blood was sampled 17 days precalving, on the day of calving and on days 1, 2, 3, 4, 7, 14, 28 and 35 postcalving. Precalving plasma concentrations of insulin-like growth factor-1 (IGF-1) increased (P<0.05) quadratically with increasing pasture intake. Concentrations of growth hormone declined (P<0.05) linearly and concentrations of non- esterified fatty acids declined (P<0.001) quadratically with increasing DM intake. Plasma concentrations of these metabolites postcalving showed no effect of precalving feeding. Level of feeding precalving did not affect milk yield or the yield of fat, protein or lactose in milk, but postcalving DM intake was negatively (P<0.1) related to precalving DMI. These results indicate that 0.93 MJ metabolisable energy/kg LW0.75 was required in the final three weeks of gestation to maintain cow energy balance. },
	issn = {1176-5283},
	author = {Roche JR and Kay JK and Kolver ES and Aspin PW and Lee J and Sugar B and Napper AR}
}
@conference {41495,
	title = {Fumarate reduces methane production from pasture fermented in continuous culture},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {64},
	year = {2004},
	month = {Jan},
	pages = {155-159},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Hamilton},
	abstract = {This experiment tested the hypothesis that addition of an organic acid (fumarate) would increase the energy captured from a pasture diet during ruminal fermentation. Pasture was fermented with 0, 10, 20, or 30 mM of fumarate constantly infused into four dual-flow continuous culture fermenters. Digestion characteristics responded linearly (P<0.05) as fumarate increased from 0 to 30 mM. Increasing fumarate from 0 to 30 mM reduced (P=0.057) methane production by 38\%, and reduced the ratio of acetate:propionate (2.4 v.s. 1.5). Concentrations of propionate and total volatile fatty acids increased by 74\% and 19\%, respectively. These results were consistent with fumarate acting as an electron-accepting intermediary in the succinate-propionate pathway. The addition of fumarate increased energy capture from a pasture diet by improving the supply of glucogenic compounds and reducing losses to methane emissions. },
	issn = {1176-5283},
	author = {Kolver ES and Aspin PW and Jarvis GN and Elborough KM and Roche JR}
}
