Digestive aspects of Holstein heifers pregnants

• Ano de defesa: 2018
• Autor(a) principal: Pereira, Jéssica Marcela Vieira
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: eng
• Instituição de defesa: Universidade Federal de Viçosa
• Palavras-chave em Português: Bovinos de leite - Nutrição; Bovinos - Gestação; Gado holandês; Nutrição e Alimentação Animal
• Link de acesso: http://www.locus.ufv.br/handle/123456789/22136

As for the nutrition of pregnant heifers, there is a lack of information on the digestive aspects. This study, for example, for the estimated day of gestation (DG) in Holstein heifers on intake, digestibility, intake, passage and digestion rates, ruminal flow, and blood metabolites of pregnant Holstein heifers. These measures were measured in 12 pregnant Holstein heifers, and of these 8 fistulated in the rumen at 150, 205 and 260 days of gestation (DG). The animals received a diet with corn silage, soybean meal, corn meal, minerals and vitamins in a ratio of bulky: concentrate of 50:50. The GMD during the study was 0.9 kg / day. Total fecal samples were collected to estimate the digestibility of dry matter (DM) and dietary nutrients: organic matter (OM), crude protein (CP) and neutral detergent fiber (NDF), water consumption, digesta omasal for bacterial isolation and ruminal flow estimation. Also, ruminal contents were emptied in order to obtain the rates of passage and digestion of DM and nutrients. Blood collections were collected to analyze metabolites (NEFA, BHB, urea, and glucose). Weights and biometric measurements were performed at the end of each collection period to evaluate the development of the animals. The data were analyzed according to a completely randomized design, using the MIXED procedure of the SAS (SAS, 2008), ruminal and omasal pH measurements were included in the statistical model as time- repeated measures, differences were declared when P <0.05. Higher intakes of DM, OM, CP and NDF (kg / d) were found at 205 compared to 150 DG. In relation to DMI in % BW there was reduction from 205 to 260 DG. For ruminal flow and digestibility, no difference was observed for the parameters of DM, OM, CP and NDF, the same was observed for microbial protein synthesis, digestion parameters and ruminal pool of DM and NDF throughout the gestation periods evaluated. The apparent total digestibility of DM, OM and CP increased from 150 to 205 DG and for NDF no change was observed. The glucose content decreased in the last evaluated period in relation to the first one, there was an increase of beta-hydroxybutyrate and AGNE at the 260 DG when comparing with the 150 DG. Among the measurements performed, only the measurements of height of withers and body length showed a difference between the evaluated periods. Our results demonstrate an increase in the digestibility of DM, OM and CP from 205 DG and that ki, kp and kd of heifers in gestation do not change during pregnancy. Also, there was a reduction of DMI in relation to CP at the end of gestation as predicted by the NRC (2001) in 14.28%, reaching consumption of 1.47% BW at 260 DG. The values found for blood metabolites do not indicate metabolic diseases. Likewise, the observed pH values are in agreement with the expected after consumption of the diet. Studies evaluating such factors are few in the literature, so more research is needed to consolidate such results.