Comportamento ingestivo de ovelhas submetidas ou não à restrição nutricional durante a gestação

Abstract

Foi avaliada a influência da gestação, do número de fetos e da restrição nutricional no comportamento ingestivo de 24 ovelhas Santa Inês avaliadas aos 90, 110 e 130 dias de gestação, divididas entre os tratamentos em função do número de fetos. Essas receberam dietas à vontade ou restritas, sendo essa com redução de 15% nos requisitos de proteína e energia. As ovelhas foram observadas individualmente, a cada 5 minutos, por 3 dias, sendo dois períodos de 24 h intercalado com 24 h de descanso. Durante as observações foram determinando os tempos gastos com ingestão, ruminação, ócio e mastigação. O manejo nutricional não influenciou o tempo gasto com a ingestão. Em ambas as categorias de prenhez, aos 90 dias de gestação, as ovelhas despenderam menos tempo para ingestão do alimento. Animais recebendo dieta restrita ruminaram mais tempo e aos 90 dias de gestação despenderam menos tempo ruminando. Ovelhas gestantes de dois fetos gastaram menos tempo mastigando do que as de gestação simples. O avanço da gestação aumentou o tempo despendido com ingestão, ruminação e mastigação. A restrição nutricional aumentou o tempo em ócio de ovelhas com um feto. Animais gestantes de um e dois fetos apresentaram comportamento ingestivo variável nas fases da gestação estudadas.

Consumo, Digestibilidade E Taxa De Passagem Ruminal Em Ovelhas Gestantes

“…The exact mechanism by which intake is inhibited due to the smaller rumen space is unknown, but it might be due to discomfort in the gastrointestinal tract ( VAN SOEST, 1994). BENEVIDES et al (2011), studied sheep with simple and twin pregnancy, under food restriction or not, and observed that the progress of gestation increased the time spent eating, ruminating and chewing, probably trying to select the ingredients looking for more fermentable parts. CARVALHO et al (2006) studied Alpine lactating goats receiving different levels of neutral detergent fiber in the diet, and found a reduction in the time of intake when the diet had greater amount of grain.…”

“…Furthermore, circulating concentrations of estrogen, progesterone and prolactin could also be responsible for changes in the passage rate of digesta (URESTE, 2001). According to MACEDO JUNIOR et al (2010) and BENEVIDES et al (2011), in late pregnancy, greater amount of grains is included in the diet of sheep, which may also contribute to the increase in passage rate.…”

“…At the end of pregnancy, besides the increase in nutritional requirements caused by the rapid growth of fetuses, two other factors negatively contribute to energy balance/ reduction of the energy use from food and less appetite due to the decreased volume of the gastrointestinal tract promoted by the largest space occupied by the fetus and annexes. However, the consumption reduction is proportionately smaller than the decrease in rumen volume, probably due to the increased passage rate (MACEDO JUNIOR et al, 2010;BENEVIDES et al, 2011). Several mechanisms may explain the causes of increased passage rate with the progress of gestation.…”

“…Regarding the physical aspect, the pressure exerted by the uterus in the rumen, reticulum, omasum and abomasum may stimulate motility and increase in intra-ruminal pressure. It can increase the sensitivity of rumen receptors resulting in increased propulsive activity during late gestation (MACEDO JUNIOR et al, 2010;BENEVIDES et al, 2011). Furthermore, circulating concentrations of estrogen, progesterone and prolactin could also be responsible for changes in the passage rate of digesta (URESTE, 2001).…”

“…On the other hand, energydeficient diets cause problems during gestation in sheep, with consequent production of fragile lambs weighing below average. Accordingly, maternal nutrition during prenatal period can be a determining factor in the ability of the matrix sheep to produce milk during lactation (COSTA et al, 2003;PEDROSO et al, 2004;LUO et al, 2004a;LUO et al, 2004b;LUO et al, 2004c;LUO et al, 2004d;LUO et al, 2004e;LUO et al, 2004f;PODLESKIS et al, 2005;MARIZ et al, 2007;TURINO et al, 2007;MACEDO JUNIOR et al, 2009;MACEDO JUNIOR et al, 2010;BENEVIDES et al, 2011).…”