Exigências nutricionais de vacas Nelore em lactação e de bezerros, do nascimento à desmama

• Autor(a) principal: Fonseca, Mozart Alves
• Data de Publicação: 2009
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/5653
• topic: Bezerros; Exigências; Nelore; Vacas em lactação; Calves; Requirements; Nelore; Lactating cows; CNPQ::CIENCIAS AGRARIAS::ZOOTECNIA::NUTRICAO E ALIMENTACAO ANIMAL

The experiment was conducted to determine the nutritional requirements (energy, protein, macro minerals) of Nellore cows and their calves from birth to six months of age. A total of 40 Nellore, 20 cows and 20 calves, with average initial weight of 362 ± 25 and 30 ± 3 kg, respectively, were used. The calves were fed individually for periods of 90 to 180 days after calving cows. The cows were divided into maintenance (4) and performance (12) up to 90 days and also from 90 to 180 days postpartum. The calves were divided into 90 and 180 days, without food restriction. Eight animals were used as reference (four cows and four calves) The diet consisted of corn silage (CS) and concentrated with forage to concentrate ratio of 70:30 for the cows, and the CS provided ad libitum together with 0, 5 kg / day of concentrate to calves. The intake of dry matter and nutrients were calculated weekly from the laboratory analysis of food provided and leftovers were computed and discounted. Milk production was determined weekly by the method of weigh-suckle-weigh . Digestibility trials were carried out every 28 days (cattle) and another two for the calves. Fecal excretion was determined using the neutral detergent fiber indigestible (iNDF) as an indicator. Animals weights were taken every 28 days. Milking was performed every 28 days to measure the levels of fat, protein and lactoses in milk. The energy concentration, expressed in TDN was calculated from the nutrients disgestibilities. The diet energy concentration was obtained by the equation DE (Mcal / kg) = 5.65 x CPD + 9.39 x EED + 4.15 NDFD + 4.15 x DNFC. The content of protein, energy and minerals were estimated by the equation Y = a. Xb, where X is the empty body weight (EBW) and, a and b are the parameters of the allometric equation. Relations were obtained for average 0.894 (EBW / BW) and 0.936 (EBW / BWG) for cows and 0.9622 (EBW / BW) and 0.958 (EBW / BWG) for calves, respectively. The net energy for maintenance of cows (NEm) were 97.84 kcal/EBW0, 75 and the metabolizable energy for maintenance (EMm) were 140.17 kcal/EBW0, 75. The efficiencies of energy uses for xi maintenance and weight gain were respectively 0.70 and 0.44. The content of protein and minerals, except calcium, decreased with the increase in BW while the energy increased. The milk of cows had average contents of 3.71, 3.88 and 4.74%, respectively, for crude protein, fat and lactoses. We conclude that the requirements for NEm lactation of cows are 97.84 kcal/PCVZ0,75, while MEm are 140.17 kcal/PCVZ0, 75, the metabolizable protein requirements are 52, 8 g / kg of milk and to produce 1 kg of milk with 4% fat, nursing Nellore cows needs of 0.300 kg of TDN. For calves, the net requirements of protein and energy increased with increasing body weight, while the calcium decreased. The metabolizable protein requirements for gain of 1 kg BW were 216.96 and 261.98 g for calves with100 and 200 kg respectively. It is recommended to use the following equations to estimate the body content of Nelore infants: Protein (g / day) = 0.135 x PCVZ1, 0351; Energy (Mcal / day) = 1.1798 x PCVZ1, 1805; Ca (g / day ) = 0.091 x PCVZ0, 6019, P (g / day) = 0.00894 x PCVZ0, 9629; Na (g / day) = 0.00126 x PCVZ0, 9791, Mg (g / day) = 0.000405 x PCVZ0 , 9827; K (g / day) = 0.00165 x PCVZ0, 9364.