Ganho médio de peso e desempenho reprodutivo de novilhas leiteiras suplementadas com minerais orgânicos e inorgânicos

Abstract

A total of 50 dairy heifers were divided into two groups according to its mineral supplementation: organic (T1, n = 25) and inorganic (T2, n = 25) treatments. The animals were fed with these supplements for 10 months (July/2005 to April/2005), when three experiments were conducted. Experiment 1: the animals where tape-weighted during 10 months. There was no statistical weight gain differences between the groups (P>0.05). Experiment 2: between September and December 2004, blood samples were collected from the heifers of both groups to measure progesterone (P4) serum levels. The animals did not demonstrate different P4 levels in September and December, although presenting statically different P4 mean levels (P<0.05) in October and November, with 1.1440 and 1.2847 ng/ml for T1, and 1.5138 and 1.6147 ng/ml for T2, respectively. This rise in P4 serum levels for T1 group does not insure that inorganic treatment is more efficient. Experiment 3: A heat protocol together with an artificial insemination with fixed time (A.I.) was realized in April 2005, to evaluate the presence of corpus luteum prior to synchronization, follicular development, ovulation rate, and pregnancy rate, using an gynecological ultrasound. Organic minerals promoted an increase in ovulation rate in the first examination after A.I. (P<0,05). Altogether, its judged necessary an higher number of studies to efficiently evaluate the effects of these new available mineral complexes on animal reproduction.