@conference {69532,
	title = {Blood metabolic profiles in Uruguayan Holstein and Uruguan Holstein x New Zealand Holstein-Friesian dairy cows},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {70},
	year = {2010},
	month = {Jun},
	pages = {311-315},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {Blood metabolic profiles were determined from 40 days prepartum to 60 days postpartum in Uruguayan Holstein (UH) (n = 13) and UH x New Zealand Holstein-Friesian first cross (UH-NZHF) (n = 13) cows with seven in each group experiencing their second lactation (L2) and six experiencing their third lactation (L3). Non-esterified fatty acids increased around calving and tended to be greater in UH-L3 cows as well as betahydroxybutyrate concentrations for 20 days after calving, consistent with the greater body condition score losses in this group. The UH cows had greater prepartum total protein concentrations than UH-NZHF cows. Concentrations decreased around calving and increased immediately thereafter. In UH-NZHF-L2 cows, total protein levels were consistently low throughout lactation. UH-NZHF L3 cows had greater albumin concentrations than UH L3 cows. Insulin concentrations were not affected by strain or lactation number and were diminished around calving. A similar pattern was found for IGF-1, although an interaction between strain and days-in-milk was found. Compared to UH cows, UH-NZHF cows had greater levels of IGF-1 at 35 days prepartum but lower levels of IGF-1 at calving. These data suggest that UH cows, especially L3 cows, had a more pronounced negative energy balance than UH-NZHF cows that may reflect a different pattern of nutrient partitioning possibly related to different pregnancy rates.},
	issn = {1176-5283},
	author = {Periera I and Laborde D and Lopez-Villalobos N and Ruprechter G and Carriquiry M and Meikle A}
}
@conference {69531,
	title = {Productive and reproductive performance of Uruguayan Holstein and Urugyayan Holstein x New Zealand Holstein Friesian cows in a predominantly pasture-based system},
	booktitle = {Proceedings of the New Zealand Society of Animal Production},
	volume = {70},
	year = {2010},
	month = {Jun},
	pages = {306-310},
	publisher = {New Zealand Society of Animal Production},
	organization = {New Zealand Society of Animal Production},
	address = {Palmerston North},
	abstract = {The performance of Uruguayan Holstein (UH) and UH x New Zealand Holstein Friesian first cross (UHNZHF) cows was investigated over 1 year using 62 cows offered predominantly native pasture. Accumulated 305 day yields of milk, fat, protein and milksolids (fat+protein) were not affected by the strain. The UH cows produced 0.5 L/d more milk than UH-NZHF cows at Day 240 of lactation (P <0.05). Fat and lactose percentages were greater in UH-NZHF cows (3.72 vs 3.44\% and 5.02 vs 4.94\%, respectively, P <0.0001). Protein percentages tended to be greater in UH-NZHF cows (3.31 vs 3.27\%, P = 0.08). The UH cows were 49 kg heavier (569 vs 520 kg, P <0.001) and required a greater energy requirement for maintenance. The UHNZHF cows produced more milksolids per kg of BW0.75, (P <0.01). Pregnancy rates tended to be greater in UH-NZHF cows (87 \% vs 71\%, P = 0.08) and were greater when the first 40 days of service were considered (61 vs 35\%, P = 0.04), which may be related to a differential energy partitioning according to strains.},
	issn = {1176-5283},
	author = {Periera I and Laborde D and Carriquiry M and Lopez-Villalobos N and Meikle A}
}
