Portal de Pesquisa da BVS Veterinária

Tese em Português | VETTESES | ID: vtt-207181

Resumo

Com o objetivo de se avaliar os efeitos da dieta sobre a ruminacao e, da ruminacao sobre a gordura do leite, uma meta-analise foi conduzida. E com o intuito de se estudar o efeito dos acidos graxos de cadeia media sobre o metabolismo e producao animal, dois experimentos foram conduzidos. No primeiro experimento foi conduzida uma meta-analise com o objetivo de entender a variacao do tempo de ruminacao e comportamento alimentar e a relacao com a gordura do leite. A meta-analise incluiu 115 artigos em ingles entre os anos de 1986 e 2017, que reportaram dados de ruminacao com vacas lactantes da raca holandesa. A media para o tempo total de ruminacao foi de 449 min/d. Foi observada uma relacao quadratica entre o tempo de ruminacao (min/d) e a producao de leite (kg/d; R2= 0,22), %gordura no leite (R2=0,08). O modelo da analise multivariada para predicao do tempo total de ruminacao incluiu producao de leite, concentracao de gordura e CMS (Tempo total de ruminacao, min/d= 96,73 + 9,96 x leite + 64,10 x % gordura 4,86 x CMS; total R2= 0,37e RMSE = 79,72). O segundo experimento teve como objetivo avaliar o efeito da suplementacao de oleo de coco sobre as taxas de biohidrogecao (BH) do acido linoleico (AL) utilizando uma abordagem in vivo. Foram utilizadas quatro vacas da raca holandesa em um delineamento cross over com dois tratamentos. No tratamento controle foi infundido uma unica dose de 200 g de oleo de cartamo e 12 g de C17:0 via canula ruminal. O tratamento com oleo de coco (COO) foi infundido 430 g de oleo de coco via canula ruminal + uma unica dose de 200 g de oleo de cartamo e 12 g de C17:0 via canula ruminal. O COO nao afetou o consumo de materia seca (CMS), a producao de leite e a gordura do leite. O COO nao afetou a taxa de desaparecimento do C:17:0 com media de 6,9%/h e 7,5%/h para os tratamento controle e COO respectivamente, mas aumentou o pH ruminal (6,6 vs 6,5) e a concentracao de C18:1 trans-11 no leite. O terceiro experimento foi conduzido utilizando 20 borregos confinados, e foi avaliada a substituicao da torta de girassol pela torta de dende sobre o consumo de nutrientes, digestbilidade, parametros sanguineos, balanco de nitrogenio e sintese de proteina microbiana. Os tratamentos foram: 100% torta de girassol; 66% de torta de girassol e 33% torta de dende; e 33% torta de girassol e 66% torta de dende e 100% de torta de dende. A inclusao de torta de dende afetou cubicamente (P0,05) o consumo de todos os nutrientes, a digestibilidade da MO e NDT e o nitrogenio retido. A substituicao da torta de girassol pela torta de dende aumentou linearmente a concentracao sanguinea de NEFA.

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In order to evaluate the effects of diet on rumination and rumination on milk fat, a meta- analysis was performed. And in order to study the effect of medium chain fatty acids on metabolism and animal production, two experiments were performed. In the first experiment, a meta-analysis was conducted to understand the variation of rumination time and feeding behavior and its relationship with milk fat. The meta-analysis included 115 peer reviewed papers in English between 1986 and 2017, which report rumination data with Holsteins lactating cows. The total rumination time averaged 449 min/d. A quadratic relationship between rumination time (min/d) and milk yield (k/d; R2 = 0.22), milk fat concentration (R2 = 0.08) was observed. The final multivariant model to predict total rumination time included milk yield, milk fat concentration and DMI (Total rumination time, min/d = 96.73 + 6.96 × milk + 64.10 × fat% 4.86 × DMI; Total R2 = 0.37 and RMSE = 79.72). The objective of the second study was to evaluate the effect of coconut oil (COO) on the on biohydrogetion rates (BH) of linoleic acid (LA) using an in vivo approach. There were four Holsteins cows in a cross over desing with two treatments. The control treatment was infused in a single bolus dose of 200 g of safflower oil and 12 g C17:0 via ruminal cannula. The treatment with coconut oil (COO) was infused 430 g of coconut oil via ruminal cannula + a single dose of 200 g of safflower oil and 12 g C17:0 via ruminal cannula. The COO did not affect DMI, milk yield and milk fat. The COO did not affect the disappearance rate of C17:0 and averaged 6.98% / h and 7.54% / h for the control and COO treatments respectively. It increased ruminal pH (6.56 vs 6.47) and C18:1 trans-11 concentration in milk. The third experiment was conducted using 20 feedlot lambs, to evaluate effect of the replacement of sunflower cake for palm cake on nutrients intake and digestibility, blood parameters, nitrogen balance and microbial protein synthesis. The treatments were: 100% sunflower cake; 66% sunflower cake and 33% palm cake; 33% sunflower cake 66% palm cake and, 100% of palm cake. The Palm cake inclusion cubically affected (P0.05) all the nutrients intake, digestibility of OM and TDN and the nitrogen retained. The replacement of sunflower cake by palm cake linearly increased NEFA blood concentration. The inclusion of palm cake decreased the intake of EE, non fiber carbohydrate (NFC) and total digestible nutrients (TDN). Also decreased the organic matter, crude protein, NFC and TDN digestibility. The nitrogen retained and NEFA concentration in blood were decreased.

Biblioteca responsável: BR68.1