Qualidade das diferentes frações do leite de vacas F1 Holandês x Zebu

Abstract

The use of F1 (HxZ) for milk production, although competitive in tropical conditions they have limitations on their behavior. This study aimed to assess the temperament of zebu and F1 (H x Z) cows in different categories using three different methods, besides evaluating three methods of taming in F1 (H x Z) heifers. The experiment was conducted in southeastern Brazil in Felixlândia/MG at the Experimental Farm of EPAMIG. We used 560 females from different Zebu breeds and their F1 calves from the crossing with Holstein bull, using three methods to assess the temperament of animals: flying speed test, the reactivity test and temperament score test. All data were subjected to analysis of variance, in which the differences were compared by F, SNK or Scott Knott test according to the number of averages. The correlations between the dependent variables were tested by Pearson correlation test. We used three methods for taming F1 heifers over 24 months of different maternal bases: Nilson Dornellas' method, the application of the Nilson Dornellas' method by the employees according to the course and the method previously used in the experimental farm of EPAMIG. The data relating to taming for flying speed test and reactivity test were evaluated by regression analysis for time in days. Data from the flying speed and reactivity test were also subjected to the T test, before and after taming. Statistical analyzes were performed by means of 9.1-SAEG of the UFV program. It was observed a higher value for the flying speed (5.10 seconds) in Gir cows (P <0.05). Gir cows (726.30) and Nellore (777.49) race were less reactive and statistically similar in the SNK test. As for the temperament score test, there was difference between the Gir (2.31) and Guzonel (3.31) cows. In heifers (HXZ), Gir cows' daughters were less reactive (1377.36) similar to heifers of Nellore cows' daughters. Considering the F1 lactating cows, the 'Guzolandas', had the greatest flying speed. The daughters of Nelore cows and Zebu cows showed the lowest reactivity. In taming of heifers, it was observed positive linear behavior for flying speed as in function of the period, increasing 0.43 seconds in the flying speed test of F1 heifers for every additional day of taming, and negative linear behavior in the reactivity test. As for the taming method of the Nilson Dornellas instructor, there was a significant difference by T test (P <0.05) to beginning and end of the taming in the flying speed and reactivity tests. F1 Holstein cows in milk production to milking system, regardless of genetic composition, are less reactive than zebu cows used to produce these. F1 heifers exhibit temperament more aggressive than the F1 cows, and the use of taming methodologies of heifers before the first calving are more effective regardless of genetic composition.