Comportamento, produção e qualidade do leite de vacas Holandês-Gir com climatização no curral

This study was conducted with the objective to evaluate the duration of exposure of animals to the evaporative cooling system in the waiting barn on the weather variables (temperature and relative humidity), animal behavior, production and quality aspects of milk from Girolando cows. Sixteen multiparous lactating cows were used having a genetic composition of 7/8 Holstein-Gir and mean milk production of 18 kg animal-1day-1. A 4 × 4 Latin square design was used. The experiment was conducted during the summer season (February-March 2009) and lasted 56 days. The treatments consisted of different periods of 10, 20 and 30 minutes of exposure to acclimatization and control. Time of 30 minutes of exposure to thermal conditioning system enabled the second milking (evening shift), providing an increase in milk production in the next milking of 0.640 kg animal-1. A higher percentage of time spent on food intake and rumination (17.31 and 30.19%) in 30 minutes treatment, compared to control (15.50 and 27.37%), respectively. There was no significant effect of treatments in the composition of milk.UFRPE DTR, Campus Dois Irmãos. R. Dom Manuel de Medeiros, s/n, CEP. 52171-900, Recife, PEUFRPE/DZUNESP, Campus de Tupã, Av. Domingos da Costa Lopes, 780, CEP 17602-496, Tupã, SPUAG UFRPE, Av. Bom Pastor s/n, CEP 55296-901, Garanhuns, PEUNESP, Campus de Tupã, Av. Domingos da Costa Lopes, 780, CEP 17602-496, Tupã, S

U–Pb isotopic ages and Hf isotope composition of zircons in Variscan gabbros from central Spain: evidence of variable crustal contamination

Ion microprobe U–Pb analyses of zircons from three gabbroic intrusions from the Spanish Central System (SCS) (Talavera, La Solanilla and Navahermosa) yield Variscan ages (300 to 305 Ma) in agreement with recent studies. Only two zircon crystals from La Solanilla massif gave slightly discordant Paleoproterozoic ages (1,848 and 2,010 Ma). Hf isotope data show a relatively large variation with the juvenile end-members showing ɛHfi values as high as +3.6 to +6.9 and +1.5 to +2.9 in the Navahermosa and Talavera gabbros, respectively. These positive ɛHfi values up to +6.9 might represent the composition of the subcontinental mantle which generates these SCS gabbros. This ɛHfi range is clearly below depleted mantle values suggesting the involvement of enriched mantle components on the origin of these Variscan gabbros, and is consistent with previous whole-rock studies. The presence of zircons with negative ɛHfi values suggest variable, but significant, crustal contamination of the gabbros, mainly by mixing with coeval granite magmas. Inherited Paleoproterozoic zircons of La Solanilla gabbros have similar trace element composition (e.g. Th/U ratios), but more evolved Hf-isotope signatures than associated Variscan zircons. Similar inherited ages have been recorded in zircons from coeval Variscan granitoids from the Central Iberian Zone. Granitic rocks have Nd model ages (TDM) predominantly in the range of 1.4 to 1.6 Ga, suggesting a juvenile addition during the Proterozoic. However, Hf crustal model ages of xenocrystic Proterozoic zircons in La Solanilla gabbro indicate the presence of reworked Archean protoliths (TDM2 model ages of 3.0 to 3.2 Ga) incorporated into the hybridized mafic magma

Isotopic evidence from the Ivrea Zone for a hybrid lower crust formed by magmatic underplating

The large mafic complex overlying mantle peridotites in the Ivrea Zone of northern ltaly originated by underplating of mantle-derived magma onto the base of continental crust, and may be a unique outcrop of typical mafic lower crust, sampled elsewhere only by mafic xenoliths. Neodyrnium and strontium isotope data show that the magmas assimilated large and roughly uniform proportions of crustal material. The resulting hybrid magmas have the same isotopic signature as, and may represent the lower-crustal 'roots' of, upper-crustal Hercynian granitoid intrusions