Rações com diferentes fontes de gordura para vacas em lactação

• Autor(a) principal: Costa, Marcone Geraldo
• Data de Publicação: 2008
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/1700
• topic: Bovino de leite; Nutrição; Lipídios; Dairy cattle; Nutrition; Lipid; CNPQ::CIENCIAS AGRARIAS::ZOOTECNIA::NUTRICAO E ALIMENTACAO ANIMAL

The experiment was conducted to evaluate the effect of the dietary supplementation with lipid sources in different forms of offering (free or partially protected) on the productive performance, intake and dynamics of nutrients, fatty acids profile and content of conjugated linoleic acid (CLA) in milk, blood parameters and estimation of microbial synthesis. Ten Holstein cows were distributed in two 5 x 5 Balanced Latin Squares. The experimental diets were composed of control, without additional fat source, and diets with addition of calcium salts, soybean oil, ground whole soybean seed, ground whole soybean seed treated with formaldehyde. Intakes of dry matter (DMI) and organic matter (OMI) was lower in the diets supplemented with lipid sources as related to control, regardless of offering forms, while higher ether extract intake (EEI) were observed in the diets with additional lipids sources. Lower neutral detergent fiber intake (NDFI) was observed in diet with calcium salts. Diet with soybean oil produced the lowest values of apparent digestibilities for dry matter (ADDM), organic matter (ADOM), total carbohydrates (ADTC) and digestibility of neutral detergent fiber (DNDF). Apparent digestibility of protein was lower in diet with ground whole soybean seed treated with formaldehyde. Milk production was not influenced by addition or offering forms of lipids in any of the diets, but higher depression of milk fat was observed when calcium salts was added to diet, while the lowest amount of milk protein was observed in diet containing ground whole soybean seed treated with formaldehyde Lower passage rates of particles of forage and soybean meal were observed when soybean oil was used in the diet. The degradability of the NDF was lower in the diet with ground whole soybean treated with formaldehyde. Lipids sources (free or partially protected) were effective in promoting reduction of short- and medium chain fatty acid and saturated fatty acids and increase the long chain fatty acids and unsaturated in milk. Values of CLA were similar among diets with lipid sources; regardless of the source and higher then control diet. Values of nitrogen balance were positive, however lowest values were for diet with grain, soybean, followed by soybean oil. Higher nitrogen(N) excretions in feces and greater N retention expressed by the lower excretion N in urine and milk was observed in diet with ground whole soybean seed treated with formaldehyde. The concentration of urea in serum and milk were lower hen ground whole soybean seed treated with formaldehyde was used in the diet, indicating the influence of complexation in the metabolism of protein in the rumen and post-rumen. Higher allantoin excretion and microbial nitrogen estimation was observed in the control diet, however the efficiency of microbial synthesis was similar among diets, except for diets with calcium salts diet that resulted in lower efficiency of microbial synthesis. There was no difference among diets with respect to levels of glucose, very low density lipoprotein and high-density lipoprotein and triacilglicerides estimates in blood. Total cholesterol levels and estimated levels of low- density lipoprotein were higher in the diet with lipids sources as related to control diet. Supplementation of lipids, free or partially protected, in different forms, in the level used in this experiment, for cows in the middle of lactation, are effective in promoting changes in the fatty acids profile from milk, without affecting the production of milk, however milk components, particularly milk fat are affected.