RESUMO O objetivo do presente trabalho foi determinar e comparar o perfil metabólico de vacas Holandês (H) e mestiças Holandês x Jersey (HxJ) no periparto. Avaliaram-se 24 vacas, sendo 11 vacas Holandês e 13 mestiças Holandês x Jersey. Semanalmente, coletou-se sangue para a determinação das concentrações séricas de glicose, beta-hidroxibutirato (BHB), proteína total, albumina, aspartato aminotransferase (AST), creatinoquinase (CK), cálcio total, cálcio iônico, magnésio, fósforo inorgânico e colesterol. Avaliou-se também o peso vivo e o escore de condição corporal (ECC). Os dados foram submetidos à análise de variância com medidas repetidas no tempo. As vacas Holandês apresentaram maior peso vivo. Não houve diferença entre os grupamentos genéticos para ECC. Foi observada tendência de maiores concentrações séricas de BHB, AST e maior concentração de cálcio iônico em vacas mestiças Holandês x Jersey. Vacas mestiças Holandês x Jersey e Holandês apresentaram perfil energético similar durante o período de transição pré e pós-parto na maioria dos indicadores, com exceção do cálcio, que foi maior nas vacas mestiças, e do fósforo, que foi superior nas vacas Holandês.

Nitrogen nutrition of sole maize crops is problematic in 'no-input' agricultural systems. The ability of the N, fixing cover crops. Mucuna pruriens var. uti/is and Pueraria phaseoloides. to sustain annual c-ropping of sole maize was tested from 1997 to 2000, with the fallow biomass either burned or retained. In 1997In , 1999In and 2000. maize grain dry matter yield was significantly higher after M. pruriens and P. p!wseo!oides than after natural fallow regrowth. The !'allow type had no effect on grain yield in 1998. Burning of the biomass before planting maize increased grain yield in 1998 but had no etlect in 1997. 1999 and 2000. The cumulative grain yield over 4 years was 9.14 Mg ha-1 in the natural fallow regrowth, significantly less than after M. pruriens (II .73 Mg ha· 1 ) and P. plwsm!oides ( 12.54 Mg ha 1 ). Burning the biomass. although nonsignificant in 3 out of 4 years, had a cumulative advantage with 11.72 Mg ha-1 grain yield. compared with biomass retention (I 0.55 Mg ha··l. p = 0.0 19). The economically important yield of marketable cobs was on average approximately US$ 320 ha-1 year-1 higher after burned P. plwseo/oides cover crop than after burned natural fallow regrowth. The lack of a positive yield response to biomass and thus N retention was related to problems of maize establishment. The nitrogen contained in the aboveground cover crop biomass appears not to he essential for maize nutrition under the site conditions.

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The indiscriminate use without criteria of nitrogen fertilization can lead to an accumulation of nitrate in pastures, animal poisoning and potential increase in residual content of this compound in milk. The objective of this study was to determine the residual levels of nitrate throughout the year in pastures and milk from small farms in western Santa Catarina (SC) that use high levels of nitrogen fertilization. The experiment was carried out from April/2018 to March/2019 on 10 dairy farms in the municipality of Riqueza (SC). Two annual collections of water samples and monthly collections of pastures and milk were carried out, in addition to obtaining information on the property and management of pasture fertilization through a structured questionnaire. Nitrate was also evaluated in pastures using the diphenylamine test. Temperature and rainfall data were obtained daily by a weather station. The average amount of nitrogen fertilizer used in the properties was 654 ± 176 kg/ha/year. The average nitrate content in the drinking water of the animals was 1.5 ± 1.4 mg/L, in the pasture it was 270 ± 76 mg/kg DM, while in milk it was 2.0 ± 0.3 mg/L. There was seasonal variation with an increase in nitrate content in pastures and milk in autumn, a period of the experiment in which low rainfall was observed. It was concluded that despite being dairy properties with high use of nitrogen fertilization, safe milk is produced in terms of nitrate levels, even in times of the year with adverse climatic conditions. The diphenylamine test has a good ability to discriminate the nitrate content in pastures and can be indicated as a quick test to verify the presence of high levels of nitrate in the pasture.

The defatted dry extract (DDE) comprises of the solid constituents of the milk, except for the fat, and must have a minimum established content of 8.4% for raw milk in Brazil. The objective was to evaluate the effects of commercialized milk volume, somatic cell count (SCC) and total bacterial count (TBC) on the DDE content of dairy farm milk samples. The sampling included data from monthly milk analyzes of dairy farms, which supply four dairy industries located in the state of Santa Catarina, Paraná and Rio Grande do Sul, and comprised of 106.470 observations sampled in 2015.The data were submitted to variance and regression analysis. To evaluate the influence of the volume of milk commercialized by the farmers, the SCC and TBC levels, and the levels of DDE, the values of these explanatory variables were stratified in quintiles. The mean DDE was 8.55%, with 25.6% of the samples being below the established minimum. In regard to the volume of milk marketed by the farmers, seasonal variations were observed in all quintiles of dairy farms analyzed, but with lower levels of DDE in milk samples from small farms throughout the year. Samples of milk with high TBC and, especially high SCC, presented lower percentage of DDE during the year. It is concluded that the DDE content of milk is related to the season of the year, the production volume per dairy, SCC and TBC.