Abstract The aim of this study was to evaluate the association of different concentrations of Trolox® and the addition of a fixed concentration of DHA in the freezing of semen of Mangalarga Marchador stallions. To that end, 16 ejaculates were frozen in the following extenders: E1) BotuCrio® (BC; Control); E2) BC + 50 ngml-1 DHA + 30 µM Trolox® (BCDHA30T); E3) BC + 50 ngml-1 DHA + 40 µM Trolox® (BCDHA40T); E4) BC + 50 ngml-1 DHA + 50 µM Trolox® (BCDHA50T). All the tested extenders were similar in preserving different kinematic parameters, cell functional integrity, compacted DNA, and high and intermediate mitochondrial activity (P>0.05). However, sperm cryopreserved in BCDHA40T showed higher velocities than sperm frozen in the control extender (P<0.05). The 30 µM concentration of Trolox® was worse for sperm motility and the 50 µM concentration of Trolox® did not adequately preserve the structural integrity of the membranes in an extender containing DHA when compared to the BotuCrio® (P<0.05) extender. The use of Trolox® in freezing extenders containing DHA did not maximize the effect of BotuCrio®, except for in the case of sperm velocity parameters when at a concentration of 40 µM.

Trinta e dois cordeiros (16 machos e 16 fêmeas) deslanados mestiços de Santa Inês, criados com as matrizes em pastagem de Brachiaria humidicola e suplementados em creep-feeding no período noturno, foram distribuídos em delineamento inteiramente casualizado, em esquema fatorial 4x2 - quatro idades de desmame (56, 70, 84 e 98 dias) e sexo, com o objetivo de determinar a melhor idade para o desmame desses animais. Ao desmame, os cordeiros foram confinados, até completarem 126 dias de vida, em baias individuais, onde receberam feno de Tifton 85 (Cynodon spp. cv Tifton 85), água e sal mineral ad libitum e ração concentrada na proporção de 2% do peso vivo. Houve efeito significativo da interação dos fatores idade de desmame e sexo sobre GPC e GPD, em que os cordeiros desmamados aos 84 dias foram superiores às cordeiras desmamadas com a mesma idade. Não se observou efeito significativo na interação dos fatores idade de desmame e sexo sobre GPND e CAC. Verificou-se efeito quadrático da idade de desmame para as variáveis GPND, GPD e CAC. Não se observou efeito significativo do sexo em nenhum dos parâmetros avaliados. A idade de desmame de 76 dias proporcionou maximização dos parâmetros GPND e GPD, enquanto a CAC mais eficiente foi observada nos animais desmamados aos 72 dias.

Thirty-two crossbred Santa Inês hair sheep lambs (16 males and 16 females) bred with their female progenitors on pasture of Brachiaria humidicola grass, supplemented in creep-feeding during the night, were allotted to a completely randomized design, in a factorial arrangement 4 x 2, four weaning ages (56, 70, 84 and 98 days) and sex to determine the best weaning age. At weaning, the lambs were confined in individual pens until 126 days old, when were daily fed Tifton 85 hay, water and mineral salt ad libitum and concentrate diet in the proportion of 2% body weight. There was a significant effect of weaning age vs sex interaction on DWC and DWG, where the males weaned at 84 days old were heavier than the females. No significant interaction of weaning age vs sex on DWBW and CFC was detected. Quadratic effects of weaning age on DWBW, DWG and CFC were noticed. No significant effect of sex on any of the studied parameters was detected. Seventy-six days weaned lambs maximized DWBW and DWG, while the most effective CFC was observed in seventy-two days weaned animals.