Dietas contendo silagem de milho (Zea maiz L.) e feno de capim-Tifton 85 (Cynodon spp.) em diferentes proporções para bovinos.

Avaliaram-se o consumo, a digestibilidade, o pH e concentração de amônia ruminais e a taxa de passagem em bovinos alimentados com dietas contendo feno de capim-tifton 85 (TIF) e silagem de milho (SM) em diferentes proporções. Utilizaram-se quatro animais castrados, com peso médio de 523kg, fistulados no rúmen, distribuídos em um quadrado latino 4 x 4, recebendo 60% de volumoso e 40% de concentrado, na base da matéria seca. O volumoso consistiu das seguintes proporções (%): 100 TIF:0 SM; 67 TIF:33 SM; 33 TIF:67 SM e 0 TIF:100 SM. Os consumos de matéria seca (MS), de matéria orgânica (MO) e de matéria orgânica digestível (MOD), de proteína bruta (PB), de fibra em detergente neutro (FDN) e de carboidratos totais (CHOT) e digeríveis (CHOD) não foram influenciados pelas diferentes proporções de feno de capim-tifton 85: silagem de milho nas dietas, registrando-se valores médios de 9,2; 8,7; 6,4; 1,1; 3,7; 7,3 e 5,4 kg/dia, respectivamente. O consumo de extrato etéreo (EE) elevou linearmente com o aumento da silagem de milho nas dietas. As digestibilidades aparentes da MS, MO, PB, EE e CHO também não foram influenciadas pelas diferentes proporções de silagem de milho, obtendo-se, respectivamente, valores médios de 71,8; 73,0; 69,5; 69,2 e 73,9%. Para a digestibilidade da FDN, observou-se efeito quadrático, estimando-se valor máximo de 65,2% para dietas contendo 30,98% de silagem de milho. Estimou-se concentração máxima de amônia de 12,0 mg/100 ml e valor mínimo de pH de 5,98 às 2,44 e 6,82 horas após a alimentação, respectivamente. A taxa de passagem não foi influenciada pelas diferentes proporções de feno:silagem, no volumoso, apresentando valor médio de 4,2%/hora. Corn silage and Tifton 85 Bermudagrass Hay-Based Diets for Steers. ABSTRACT - The intake, digestibility, ruminal pH and ammonia concentrations and passage rate were evaluated in steers fed corn silage (CS) and Tifton 85 bermudagrass hay (T85H)-based diets, at different forage proportions. Four rumen fistulated steers with 523 kg of live weight were used in a 4x4 latin square design, and fed diets containing 60:40 forage:concentrate proportions in dry matter basis. The forage portion consisted of: 100 T85H:0 CS; 67 T85H:33 CS; 33 T85H:67 CS and 0 T85H:100 CS. The dry matter (DM), organic matter (OM), digestible organic matter (DOM), crude protein (CP), neutral detergent fiber (NDF), total carbohydrates (TC) and total digestible carbohydrates (TDC) intakes were not affected by different T85H: CS proportions and averaged 9.2, 8.7, 6.4, 1.1, 3.7, 7.3 and 5.4 kg/day, respectively. The ethereal extract (EE) intake increased with increasing on corn silage proportion of the diets. The DM, OM, CP, EE and TC apparent digestibilities were not affected by increasing percentage of corn silage on rations and averaged 71.8, 73.0, 69.5, 69.2 and 73,9%, respectively. There was a quadratic effect for NDF digestibility, with maximum value of 65.2% for diets with 30.98% of CS. The N-ammonia maximum content (12.0 mg/100 ml) and minimum value of pH (5.98) were estimated 2.44 and 6.82 hours after feeding, respectively. The passage rate, which was not affected by changing T85H:CS proportions in the forage, averaged 4.2 %/hour

Milk fatty acid composition of Holstein x Gyr dairy cows fed sugarcane-based diets containing citrus pulp supplemented with sunflower oil.

Abstract Sugarcane is a strategic roughage source for milk production in the tropics, and its supplementation with plant oils offers great potential for obtaining milk enriched with beneficial fatty acids, such as oleic (cis-9 C18:1), vaccenic (trans-11 C18:1), and rumenic (cis-9, trans-11 CLA) acids. The aim of this study was to evaluate the milk fatty acid composition of cows fed 60% chopped sugarcane-based diets containing citrus pulp and 0.0% (control), 1.5%, 3.0% and 4.5% sunflower oil on a dry matter basis. Twelve multiparous Holstein x Gyr dairy cows with an average milk production of 17±5 kg day-1 and 96±25 days in milk were allocated in a triplicate 4 x 4 Latin square design. There was no effect of dietary treatment on milk production, but sunflower oil supplementation linearly reduced the milk fat content and yield. The milk fat contents of lauric (C12:0), myristic (C14:0), and palmitic (C16:0) fatty acids were linearly reduced with increasing sunflower oil levels. There was a quadratic effect on the milk fat oleic, vaccenic, and rumenic acid contents, while the concentrations of elaidic acid (trans-9 C18:1), trans-10 C18:1 and trans-10, cis-12 CLA linearly increased in response to sunflower oil inclusion. Diet supplementation with sunflower oil linearly reduced both the atherogenicity and thrombogenicity indices and linearly increased the ratio between hypo- and hypercholesterolemic fatty acids in milk fat. The inclusion of up to 4.5% sunflower oil in 60% chopped sugarcane-based diets improved the nutritional quality of milk fat from Holstein x Gyr dairy cows as a result of the increased content of oleic, rumenic and vaccenic acids, which are beneficial to human health, and the concomitant reduction of hypercholesterolemic lauric, myristic and palmitic acids. However, there was an increase in the milk content of trans-10 C18:1 and elaidic acid, which are associated with deleterious effects on cardiovascular health

Supplementation levels for growing beef cattle grazing in the dry-rainy transition season.

The objective of this experiment was to study the effects of different levels of supplementation on the performance, intake, digestibility, pH and rumen ammonia concentration in growing bulls grazing Brachiaria decumbens Stapf. pasture, during the dry-rainy transition season. For evaluation of performance, intake and digestibility, it was used 25 non-castrated steers at 11 months of age and initial average body weight of 270 kg, grouped in five plots of five animals each, following a completely randomized design. Each plot received one of the following feeding treatments: mineral mixture and supplement at the proportion of 0.5, 1.0, 1.5 and 2.0 kg/animal/day, corresponding to 0.18, 0.36, 0.54 and 0.72% of the average body weight of the animals. The area designated for the animals was constituted of five 2.0-ha paddocks. For the evaluation of the pH and rumen ammonia concentration, five crossbred non-castrated steers were used, with average body weight of 240 kg, fistulated in the esophagus, rumen and abomasum, disposed in a 5 × 5 Latin square, with five treatments and five experimental periods. Animal performance behaved in a positive linear manner according to the supplementation levels, responding with an increase of more than 80% on weight gains of the animals. Intakes of total and pasture dry matter (DM), organic matter and neutral detergent fiber were not influenced by supplementation. Intakes of crude protein, nonfibrous carbohydrates, ether extract and total digestible nutrients as well as nutrient digestibility and rumen ammonia concentration showed a positive linear pattern in response to supplementation levels. Increasing levels of concentrate supplementation influence positively the performance of bulls growing on pastures during the dry-rainy transition season

Ofertas de suplementos múltiplos em tourinhos anelorados na fase de recria, em pastagens durante o período da seca: produção e eficiência microbiana.

O uso de suplementos múltiplos para bovinos visa aumentar o aporte de nutrientes, para melhor atender às exigências nutricionais. Neste contexto, avaliou-se a digestibilidade em tourinhos anelorados em fase de recria, recebendo diferentes ofertas de suplementos em pastagem de Brachiaria decumbens. A área foi dividida em cinco piquetes de 2,0 ha cada. Foram utilizados 30 tourinhos, com peso e idade iniciais médios de 230,0 ±6,14 kg e 8,5 ±0,18 meses, em delineamento inteiramente casualizado, contendo cinco tratamentos, sendo quatro ofertas de suplementos, mais mistura mineral (MM) e seis repetições. Foram avaliados a MM (60g/animal) e suplementos múltiplos, formulados para atender diferentes níveis de suplementação diariamente nas quantidades de 0,5, 1,0, 1,5 e 2,0 kg/animal e suprir 300g/dia de PB. O consumo de suplemento aumentou (P<0,10) a produção de proteína microbiana (PMic), quando comparado com os animais do grupo controle. A produção de PMic apresentou comportamento quadrático com ponto de máxima produção de 404,47 gramas na quantidade de 1,34kg de suplemento. A eficiência de síntese microbiana (EFMic) não diferiu entre os animais do grupo controle e os suplementados. Contudo, observa-se um comportamento quadrático com máxima eficiência 160,38 g/kg de NDT para oferta de 1,18 kg de suplemento. Observa-se que o ponto (1,18 kg) onde ocorreu a máxima EFMic foi inferior ao valor (1,34 kg) em que ocorreu a máxima produção de PMic. Conclui-se que, o ponto ótimo entre produção e eficiência de síntese de proteína microbiana, está entre as ofertas de suplemento diárias de 1,18 e 1,34 kg/animal

Ruminal parameters and fatty acid composition of omasal digesta and milk in cows fed sugarcane-based diets supplemented with sunflower oil.

This study evaluates the intake and digestion of nutrients, parameters of rumen fermentation and degradation, omasal digesta and milk fatty acid composition, productive performance, and the concentration of serum metabolites in cows fed 600 g kg-1 sugarcane-based diets containing 0 (control), 15, 30, and 45 g kg-1 sunflower oil (SO) on a dry matter (DM) basis. Four rumen-cannulated Holstein x Gyr cows yielding 15±5 kg day-1 with 110±10 days in milk were allocated in a 4 x 4 Latin square design. Data were analyzed using mixed models, and significant differences were declared at P<0.05. There was no effect of SO on the intake and apparent digestibility of DM, crude protein, neutral detergent fiber (NDF) and nonfibrous carbohydrates, but there was a linear increase in the intake and digestibility of ether extract. Dietary SO levels did not alter the ruminal degradability parameters for DM and NDF, rumen pH and contents of ammonia N, acetate, propionate and volatile fatty acids. Milk fat content and yield were linearly decreased, whereas a linear increase in milk protein content was observed in response to increasing levels of SO, but with no effect on milk yield. Linear reductions in palmitic and &#945;-linolenic acid contents, a linear increase in trans-10 C18:1 and elaidic acids, and a quadratic effect on vaccenic and rumenic acids were observed in omasal digesta of cows fed increasing levels of SO. Overall, up to 45 g kg-1 SO can be included on DM of chopped sugarcane-based diets without reducing consumption, apparent digestibility and rumen degradability of DM and fiber. Supplementing chopped sugarcanebased diets with 30 to 45 g kg-1 SO (DM basis) promotes milk fat depression due to the inhibition of mammary lipogenesis by specific rumen-derived fatty acid intermediates of the biohydrogenation of unsaturated C18 fatty acids. The inclusion of 15 to 45 g kg-1 SO in chopped sugarcane-based diets improves the nutritional quality of milk fat, with increases in the levels of oleic, vaccenic and rumenic acids, beneficial to human health, and a reduction in the levels of the hypercholesterolemic lauric, myristic and palmitic acids.Suplemento

Macromineral requirements by beef cattle under pasture supplementation.

The objective of this work was to determine macromineral requirements by Zebu steers grazing Brachiaria decumbens supplemented with concentrate. It was used 24 non-castrated steers, at an average age of 7 months and at initial average weight 180 kg. Eight control animals were slaughtered for determining initial body composition. The 16 remaining animals were divided in four four-animal plots, in a complete random design. Each plot received mineral mixture or supplements at the levels 0.75; 1.50 or 2.25 kg/animal/day. The right half-carcass of eight animals, two per group, was dissected in muscle, fat and bones and all body constituents were weighted for determination of empty body weight and body composition. Net requirements of calcium and phosphorus for an animal at 400 kg body weight were 11.13 g and 5.40 g, respectively. To estimate dietary requirements of maintenance and after, sum them to dietary requirements for gain in order to obtain total dietary requirements, it was adopted endogenous losses and bioavailability present in literature for each mineral macroelement. Total dietary requirement for calcium, phosphorus, magnesium, sodium and potassium for a 400-kg BW animal with 1.0-kg daily weight gain were 34.59; 17.36; 7.82; 5.19 and 41.11 g/day, respectively. Macromineral requirements by beef cattle under pasture supplementation are similar to those recommended by BR-Corte for beef cattle in feedlots

pH e força de cisalhamento da carne de cordeiros alimentados com glicerina bruta na fase de terminação.

Objetivou-se neste trabalho avaliar o efeito da inclusão de glicerina bruta (GB) na dieta de cordeiros em terminação, sobre o pH, a temperatura (TºC), a força de cisalhamento (FC) e as perdas obtidas pelo descongelamento (PDESC) e cocção (PCOC) da carne de cordeiros da raça Santa Inês