REPRODUCTIVE PARAMETERS OF NELORE MALES OF LOW AND HIGH FEED EFFICIENCY SUPPLEMENTS WITH PROTECTED FATTY ACIDS IN PASTURE

Abstract

Feed efficiency is very important for breeding programs. The residual feed intake (RFI) is an indicator that has a correction of dietary intake for animal weight and weight gain. In addition to this feature, puberty is important for the improvement of breeding cattle. The production and semen quality are influenced by several factors, especially nutrition. Polyunsaturated fatty acids (PUFA) has effect on the reproductive performance of males. But few studies have been conducted to assess the impact of genetic selection for feed efficiency in reproducing the Zebu. Addressed within the context, the aim of this work is to evaluate the effects of supplementation with PUFA in puberty and in the semen characteristics of male Nellore selected for RFI. Will be selected 50 young male bovine of 12 months of traditional herds (NeT) and selection for residual feed intake (NeS) Institute of Animal Science (IZ), Sertãozinho, SP. These animals will be divided into 3 groups: one group being supplemented with PUFA of 10 animals from the herd NeS and 10 animals the herd NeT, the second group will be supplemented with a diet isoproteic to group 1 but without PUFA consists of 20 animals (10 NeS and 10 NeT) and the third group only on pasture without supplementation consists of 10 animals (5 and 5 NeS NeT). Evaluations will be done every 28 days on the following parameters: weight, body condition score (BCS), carcass ultrasound, hormonal and metabolic. There will also be evaluated measurement of scrotal circumference, testicular ultrasound and glandular and semen collection to ascertain the seminal characteristics and subsequent cryopreservation. After thawing semen, further tests will be conducted in sperm quality and use in program in vitro embryo production (IVP)