Protein levels for Landrace and Duroc boars

Abstract

The main objective was to study the effects of several protein levels sequences of Landrace and Duroc boars reared under two feeding systems. The results of weight gain from 25 up to 100 kg live weight, showed that the best daily gain was achieved on the sequence levels of 16% protein during growing phase and 14% protein for finishing phase. This daily gain was statistically different (P <0.05) from 18-16% or 20-18% protein seguences. The best feed efficiency and the lowest feed intake were achieved on the sequence levels of 18-16% protein for growing finishing phases, respectively. These data were statistically different (P <0.05) from seguence 14-12% but were not different from sequences 16-14 or 20-18% protein. The carcass traits studied: fat thickness, loin eye area, percent of ham and relation meat/fat - showed a linear response when analyzed through regression. This linearity means that increasing protein levels in the diet, the carcass traits were improved. Carcass lenght was unaffected by protein levels. The feeding systems controlled or ad libitum did not affect performance or carcass traits of the animals. The Landrace showed the best carcass traits (P <0.05) when compared to Duroc breed.