Productive performance of Pitangueiras breed (5/8 Red Poll x 3/8 Guzerá) and Red Poll x Zebu in Brazilian tropical region

Abstract

Results are presented on productive performance fr om  the 1^st to 6^th lactations of 234 cows 1/2 Red Poll x 1/2 Zebu, 394 cows 114 Red Poll x 3/4 Guzerá and 223 cows 5/8 Red Poll x 3/8 Guzera (Pitangueiras Breed). A linear programming model and least-square analysis was used to verify the influence of environmental effects on milk production for 256 days at first lactation was 1767kg(C.V=20%); 1605kg(C.V.=24%); e 2421kg(C.V.=16%), respectively. The highest production where obtained at 4^th, 6^th and 5^th lactations with successive increase of 32, 37 an d 23 percent, resp ectively. The age of cows and the year of calving have significant effect on the milk production at 1^st lactation. The milk production of 1/2 Red Poll x 1/2 Zebu cows was significantly affected b y season of calving. The repeatabilities, as intraclasse correlation were: 0.15±0.03; 0.36±0.03 and 0.24±0.04 respec tively for the three groups.