Introduction.

The intensive dairy production demand high food offers to fill the nutritional requirements of the lactation, these cannot be provided to the peripartum cow, by the depression of the consumption and metabolic and endocrine changes occurring during of the transition period. The lower consumption of dry matter and the energy demands for high milk production, take the animal to the Negative Energy Balance (NEBAL), which must be overcome quickly to ensure a better reproductive rate and a higher milk production.

Objective.

To explore different nutritional options during the transition period, in order to reduce negative energy balance.

Materials and methods.

28 cows were used, in a semi-intensive dairy cows system, located in the tropics. Four treatments were used: TT1, control group; TT2, high energy density; TT3, non-protein nitrogen encapsulated, and TT4, monensin sodium. We analyzed hormones and metabolites related to energy, protein and minerals. By ultrasonography, it was determined the follicular dynamics and the presence of corpus luteum; likewise, we evaluated the reproductive indicators values and milk production. The sampling period up to 105 days postpartum allowed for the analysis of the first phase of lactation and covers the period in which it is expected that the dairy cow is in gestation.

Results.

Some variations were observed in the periods corresponding to the transition period for the main indicators of energy metabolism. Ovarian reactivation showed that it was not rapid, however, there was an effect on open days and reproductive efficiency.

Conclusion.

The concentrations of hormones and metabolites analyzed did not show significant variations. The effect of at least one treatment against the control was evident; likewise, there were variations in some analyzed periods. Reproductive behavior was poor.

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