Objetivou-se com este estudo avaliar o efeito do fornecimento de Acetato de Melengestrol (MGA®Premix) após IATF (inseminação artificial em tempo fixo), sobre a taxa de concepção em vacas paridas da raça Nelore. Experimento I, avaliou-se o efeito do fornecimento de 2,28g de MGA/ vaca/ dia, do dia 13 (D13) ao dia 18 (D18) após a IATF. As vacas foram divididas em dois grupos, sendo o Grupo I (n=83, controle) que foi realizado apenas IATF e Grupo II (n=104, tratado) que foi fornecido o MGA após a IATF. Experimento II, avaliou-se o efeito do fornecimento de 2,28g de MGA/ vaca/ dia, do dia cinco (D5) ao dia 10 (D10) após a IATF. As vacas foram divididas em dois grupos, sendo o Grupo I (n=94, controle) que foi realizado apenas IATF e Grupo II (n=100, tratado) que foi fornecido o MGA após a IATF. O diagnóstico de gestação foi realizado 45 dias após a IATF em ambos os experimentos. As taxas de concepção foram comparadas pelo teste de Qui-quadrado. No Experimento I, as taxas de concepção foram de 42,16% para o grupo controle e 50,0% para o grupo tratado. No Experimento II, a taxa de concepção do grupo controle (47,87%) foi significativamente maior do que o grupo tratado (28,0%). Conclui-se que o fornecimento de MGA®Premix, administrado do D13 ao D18 após a IATF não afetou a taxa concepção. Entretanto, quando fornecido do D5 ao D10, reduziu a taxa de concepção em vacas Nelore paridas.

The objective of the present study was to assess the effect of administration of Melengestrol Acetate (MGA® Premix) after FTAI, on the conception rate in lactating Nelore breed cows. Experiment I, assessed the effect of administration of 2.28 g MGA/cow/day, from day 13 (D13) until day 18 (D18) after FTAI. The cow were divided into two groups, Group I (n=83, control) that cows were submitted just to FTAI and Group II (n=104, treated) that cows received MGA after FTAI. Experiment II, assessed the effect of administration of 2.28g MGA/cow/day, from day 5 (D5) until day 10 (D10) after FTAI. The cow were divided into two groups, Group I (n=94, control) that cows were submitted just to FTAI and Group II (n=100, treated) that cows received MGA after FTAI. Gestation was diagnosed in both experiments 45 days after FTAI. The conception rates were analyzed by Qui-Square test. In experiment I, The conception rates were 42,16% for control group and 50,0% for treated group (p>0,05). In Experiment II, the conception rate of control group (47,87%) was higher than treated group (28,0%). It was conclude that administration of MGA®Premix from D13 until D18 after FTAI didn't affect the conception rate. However, when administered from D5 until D10, reduced the conception rate in lactating Nelore breed cows.

This experiment assessed the effect of feed restriction in rabbits on performance and economic viability of the activity. Sixty New Zealand White rabbits, weaned at 33 days and slaughtered at 81 days of age, were used. The design was of randomized blocks with four treatments and five replications. The treatments were, as follows: 1 - free feeding, 2 - feed restriction from 35 to 40 days of age (50 g/d/rabbit), 3 - feed restriction from 54 to 61 days of age (90 g/d/rabbit) and 4 - feed restriction from 33 to 40 days (50 g/d/rabbit) and from 54 to 61 days of age (90 g/d/rabbit). There was no difference in the performance and carcass parameters, indicating that there was compensatory growth in the rabbits that suffered feed restriction. The best gross margin was obtained with feed restriction from 54 to 61 days age. Feed restriction in growing rabbits can be adopted at different ages because it does not interfere negatively in the performance and carcass parameters. In two periods and from 51 to 61 days, feed restriction was more economically viable for the sale of live and slaughtered rabbits, respectively.