Resumo

MORALES-ALMARAZ, Ernesto et al. Serum mineral profile of lactating Holstein cows in mixed indoor-grazing systems. Agron. Mesoam [online]. 2021, vol.32, n.1, pp.45-62. ISSN 2215-3608.  http://dx.doi.org/10.15517/am.v32i1.41333.

Introduction. Minerals play a very important role in nutrition; because they are necessary for the biosynthesis of essential nutrients. Objective. To evaluate the mineral status in blood serum, mineral consumption and milk production of grazing Holstein cows supplemented with different levels of concentrated feed and time spent in the meadow of Toluca valley, Mexico. Materials and methods. Two experiments were carried out with a 3x3 Latino square design each at the Universidad Autónoma del Estado de México, carried out in the spring-summer of 2011-2012. In experiment one, the level of concentrate in the diet (3, 5 and 8 kg day-1) was evaluated in grazing cows; in experiment two, three times of permanence in the prairie were evaluated (eight continuous hours; two times of four hours post-milking; and twelve hours). In both experiments, corn silage ad libitum was offered for free consumption in the pen. The concentration of Ca, P, Mg, K, Na, Cu, Fe, and Zn was measured in blood serum and foodstuffs. Simple correlation and multiple regression analysis were performed for the study variables of mineral intake, milk production, and minerals in blood serum. Results. The level of concentrate and the time spent in the prairie affected (P <0,05) of the consumption of most of the minerals; the Ca, P, Mg, K, and Zn requirements were not met, and there was excess Fe. Regardless of the feeding strategy, the bovine blood serum mineral content was adequate for P, Na, Cu, and Fe; marginal for Ca, deficient in Mg and Zn; and there were excess of K. Conclusion. The consumption of minerals was not decisive to predict the concentration of minerals in the blood serum of dairy cows, however, it showed influence on the milk production of cows under two mixed grazing-stallproduction systems.

Palavras-chave : prairie; grazing time; concentrate levels; mineral consumption; blood serum.

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