Effect of the dry matter intake level on the sanguine profile of glucose, insulin, urea, estrogen and progesterone and concentration of IGF-I in the follicular liquid of crossbred heifers

The aim of this work was to study effect of the dry matter intake level on the concentrations of glucose, insulin, urea, estrogen and progesterone in the blood and the level of IGF-I in the follicular liquid of heifers. Twenty seven crossbred heifers were used, in three treatments: 1.2, 1.6 and 2.6 percent of the live weight of dry matter intake (DMI) daily. The sanguine concentrations of glucose and estrogen were higher in the animals with 1.6 percent of DMI and the insulin levels were higher in the animals with 2.6 percent of DMI. There was an increase in the sanguine levels of urea with the increase of the DMI. There was no effect of the DMI on the progesterone levels in the sanguine plasma collected from the jugular. The progesterone levels in caudal vena were higher in the animals with 2.6 percent of DMI. There was no effect of the DMI on the follicular levels of IGF-I.

O objetivo deste trabalho foi estudar o efeito do nível de ingestão de matéria seca (IMS/ por cento do PV) sobre as concentrações sanguíneas de glicose, insulina, urea, estrógeno e progesterona e o nível de IGF-I no líquido folicular de novilhas. Vinte e sete novilhas cruzadas foram utilizadas, distribuídas em três tratamentos: 1,2 por cento; 1,6 por cento e 2,6 por cento do peso vivo de ingestão de matéria seca por dia. As concentrações no plasma da veia jugular de glicose e estrógeno foram maiores nos animais com 1,6 por cento de IMS e os níveis de insulina foram maiores nos animais com 2,6 por cento de IMS. Houve um aumento dos níveis plasmáticos de uréia com aumento dos níveis de IMS. Não houve efeito da IMS sobre os níveis de progesterona no plasma sangüíneo coletado da jugular. No plasma sangüíneo coletado da veia cada caudal, os níveis de progesterona foram maiores (P<0,05) nos animais com 2,6 por cento de IMS. Não houve efeito da IMS sobre os níveis foliculares de IGF-I.

Evaluation of carcass characteristics and meat chemical composition of Bos indicus and Bos indicus x Bos taurus crossbred steers finished in pasture systems

The objective of this study was to evaluate the carcass characteristics (carcass weight, carcass yield, fat thickness, loin area, marbling and colour) and chemical composition of the Longissimus dorsi muscle (moisture, ash, crude protein, fat and cholesterol) of cuts with or without fat thickness, of Bos indicus and Bos indicus x Bos taurus crossbred steers finished in millet (Pennisetum americanum L.) or star grass (Cynodon plectostachyus Pilger) pasture systems, with mineral or mineral protein supplementation. Animals were slaughtered with an average body weight of 450 kg (Bos indicus) or 470 kg (Bos indicus x Bos taurus crossbreed). There was no treatments effect on carcass characteristics and meat chemical composition of cut without fat thickness. The cuts with fat thickness of steers fed millet presented the highest fat deposition. Bos indicus steers presented higher carcass yield (57.23 percent) and fat thickness (4.88 mm) compared with crossbreed (53.40 percent and 3.05 mm). There was no breed effect on chemical composition of meat. The mean levels of cholesterol concentration were 31.41 mg/100 and 37.55 mg/100g of meat with and without fat thickness