Effect of unsaturated fatty acid supplementation on digestion, metabolism and nutrient balance in dairy cows during the transition period and early lactation

The objective of this study was to evaluate the influence of unsaturated fatty acids in diets for dairy cows during the transition period and early lactation on intake, digestion and nutrient balance. Thirty-six multiparous and pregnant Holstein cows were randomly distributed to receive one of the experimental diets in the period from 35 days before the expected date of parturition to 84 days post-partum. Diets were fed as a total mixed ration and were as follows: control (C); soybean oil (SO), based on inclusion of 30 g/kg (DM basis); and calcium salts of unsaturated fatty acids (CS), based on inclusion of 30 g/kg (DM basis). Pre-partum dry matter intakes (DMI) of cows fed C, SO and CS were 11.9, 9.5 and 9.6 kg/d, respectively. Postpartum DMI was affected by experimental diets (18.5, 15.0 and 17.4 kg/d for C, SO and CS, respectively). The energy balance in the transition period of animals fed CS was 4.41 Mcal/d higher than cows fed SO and 1.3 Mcal/d higher than cows fed C. Supplementing cows with unsaturated fatty acid sources is a strategy for dairy cows in the transition perio

Bioeconomic evaluation of feeding strategies in milk production systems. 2. Alternative methodology: level of capital utilization

Objetivou-se desenvolver uma metodologia alternativa para avaliação bioeconômica de estratégias de alimentação para rebanhos leiteiros e avaliar a produtividade física e a eficiência bioeconômica de sistemas de alimentação para vacas em lactação quando utilizadas diversas estratégias de alimentação à base de volumosos para vacas de cinco níveis de produção de leite. Utilizou-se uma plataforma computacional desenvolvida com os programas CNCPS v.5.0 e planilhas eletrônicas do Microsoft Excell®, de forma a simular a produção e as exigências de nutrientes ao longo da lactação de uma vaca com cinco níveis de produção de leite. Utilizaram-se a metodologia alternativa "Ajuste para o Nível de Capital", foram observados diversos níveis de utilização de concentrados e capital gasto com alimentação por unidade de área e estimadas equações de regressão da produtividade (PROD/ha) e receita menos os custos com alimentação (LUCR/ha) por hectare, em função destes níveis. Esta metodologia não permitiu que ocorresse utilização de diferentes níveis de insumos e de capital por unidade de área, mesmo quando são avaliadas diferentes estratégias de alimentação. Os resultados obtidos comprovaram diferenças nas avaliações bioeconômicas realizadas pela metodologia "Ajuste para o Nível de Capital" em relação à "Tradicional". De modo geral, principalmente nos maiores níveis de utilização de capital por área, as estratégias baseadas em forragens de melhor qualidade apresentaram resultados superiores na PROD/ha e LUCR/ha. No entanto, nos níveis de menor utilização de capital por área, as estratégias baseadas em forrageiras de alta produtividade por hectare apresentaram melhores resultados nas variáveis analisadasThis work was carried out to development a alternative methodology for the bioeconomic evaluation of feeding strategies for dairy herds and evaluate the physical productivity and the bioeconomic efficiency of feeding systems for dairy cows when different feeding strategies forages based are used for cows of five levels of milk yield. The computational platform was developed with the programs CNCPS v5.0 and electronic spreadsheets of Microsoft Excell®, in way to simulate the production and demands of nutrients of a complete lactation for cows of different milk yield levels. Using the alternative methodology "Adjusts for the Level of Capital", were evaluated different levels of concentrate and capital expense with feeding per area unit and estimate regression equations of productivity (PROD/ha) and income over feed costs (RMCA/ha0 per hectare, in function of these levels. This methodology did not permit the occurrance of the use the different levels of input and capital per unit of area, specifically when are evaluated different feeding strategies. The obtained results showed differences in the bioeconomics evaluations carry out by the "Adjusts for the Level of Capital" methodology in relation to "Traditional" methodology. In general, mainly in the highest levels of use of capital per area, the feeding strategies based on forages of better quality showed the best results in PROD/ha and RMCA/ha. However, in the levels of smaller levels of use of capital per area, the feeding strategies based on forages of high productivity per hectare showed the better results in analyzed variable

Desempenho produtivo e composição da fração proteica do leite de vacas leiteiras sob suplementação com fontes de gordura

The objective of this study was to evaluate the use of fat sources in rations for lactating cows on the productive performance and composition of milk protein fraction. Twelve Holstein cows were used, grouped in three balanced 4 × 4 Latin squares, fed with the following rations: control; refined soybean oil; whole raw soybean; and calcium salts of unsaturated fatty acid (Megalac-E). Dry matter and nutrient intake, and daily milk production were evaluated. The samples used to analyze milk composition were collected in two alternate days and were obtained from two daily milking. Milk composition and total nitrogen, non-protein nitrogen and non-casein nitrogen ratios were analyzed. The casein, serum protein and true protein ratios were obtained by difference. Dry matter and nutrient intakes were lower when cows received the diet containing calcium salts of fatty acids, in relation to the control diet. Among the diets with fat sources, the one with whole raw soybean and calcium salts decreased milk production. There was no effect of fat sources added to the diet on crude protein, non-protein nitrogen, non-casein nitrogen, true protein, casein, casein/milk true protein ratio and serum protein. Similarly, the experimental diets did not influence the protein fractions when expressed in percentage of milk crude protein. The utilization of fat sources in diets changes milk production and composition of lactating cows, but does not influence the composition of milk protein fractions.Objetivou-se com este estudo avaliar a utilização de fontes de gordura em rações para vacas em lactação sobre o desempenho produtivo e a composição da fração proteica do leite. Foram utilizadas 12 vacas da raça Holandesa, agrupadas em três quadrados latinos balanceados 4 × 4, alimentadas com as seguintes rações: controle; óleo de soja refinado; grão de soja in natura; e sais de cálcio de ácidos graxos insaturados (Megalac-E). Avaliaram-se o consumo de matéria seca e de nutrientes, e a produção diária de leite. As amostras utilizadas para análise da composição do leite foram coletadas em dois dias alternados e foram provenientes das duas ordenhas diárias. Foram analisados a composição do leite e os teores de nitrogênio total, nitrogênio não-proteico e nitrogênio não-caseinoso. Por diferença, foram obtidos os teores de caseína, proteína do soro e proteína verdadeira. O consumo de matéria seca e de nutrientes foi menor quando as vacas receberam a ração contendo sais de cálcio de ácidos graxos em relação à ração controle. Entre as rações com fontes de gordura, aquela com grão de soja e sais de cálcio diminuiu a produção de leite. Não houve efeito das fontes de gordura adicionadas nas rações sobre os teores de proteína bruta, nitrogênio não-proteico, nitrogênio não-caseinoso, proteína verdadeira, caseína, relação caseína/proteína verdadeira no leite e proteína do soro. De forma semelhante, as rações experimentais não influenciaram as frações proteicas expressas em porcentagem da proteína bruta do leite. A utilização de fontes de gordura nas rações altera a produção e a composição do leite de vacas em lactação, mas não influencia a composição das frações proteicas do leite

Levels and degradability of crude protein in digestive metabolism and performance of dairy cows

Two experiments were conducted to evaluate the effect of the level and degradability of crude protein (CP) on the digestive metabolism and productive performance of dairy cows. In both experiments, 15 Holstein cows with 585 ± 40 kg of body weight were distributed in a Latin square design with five contemporary squares, three periods of 21 days and three treatments. In experiment 1, treatments consisted of three CP levels (130, 160 or 180 g CP/kg DM), while in experiment 2, the treatments consisted of three levels of rumen degradable protein (RDP; 80, 100 or 120 g RDP/kg DM) in diets with average of 163 g CP/kg DM. Variables evaluated in both experiments were dry matter intake (DMI), total apparent digestibility, milk yield (MY) and composition, ruminal fermentation and N balance. In experiment 1, the increase of CP from 130 to 180 linearly increased the organic matter, CP, neutral detergent fiber (NDF) and acid detergent fiber (ADF) intake (kg) and the apparent total digestibility coefficient of DM and CP. In addition, a linear increase of MY, fat corrected milk (FCM) and daily production of fat, protein, lactose, casein and total solids was observed. A linear increase in ruminal ammoniacal nitrogen (NH 3 -N) concentration and nitrogen excretion in milk, feces and urine was also observed. However, there was no observed effect on SCFA concentration. In experiment 2, the increase of the RDP from 80 to 120 increased the DMI, MY, FCM, milk protein content and digestibility coefficient of the NDF, ADF and ethereal extract. Additionally, there was an increase in NH 3 -N concentration and milk nitrogen excretion. The studies indicated that the increase of CP content up to 100 g RDP/kg DM increased the DMI and the productive performance of the cows, but also increased urine N. Thus, it is desirable that the increase of the CP through the increase of the RDP is carried out up to 100 g of RDP/kg DM, since there is elimination of nitrogen, decrease of milk yield and decrease of propionic acid in values above that level

Avaliação de cultivares de milho colhido em duas alturas de corte para ensilagem

The objective of this study was to evaluate the agronomic characteristics, bromatological-chemical composition and digestibility of 11 corn cultivars (Zea mays) harvested at two cutting heights. Cultivars D 766, D 657, D 1000, P 3021, P 3041, C 805, C 333, AG 5011, FO 01, CO 9621 and BR 205 were evaluated when they were harvested 5 cm above ground (low) and 5 cm below the insertion of the first ear (high). The experiment was designed as random blocks, with three replicates, arranged in an 11 x 2 factorial scheme. Cultivars presented similar productions of forage dry matter and grains. Percentages of stalk, leaf, straw, cob and kernel fractions were different among cultivars, as well as dry matter content of the whole plant at harvest. Considering the whole plant, only the contents of gross energy, nitrogen in neutral detergent fiber, and in vitro neutral and acid detergent fiber digestibility did not differ among cultivars. Increase on the cutting height improved forage quality due to the reduction of stalk and leaf fractions and contents of cell wall constituents.Objetivou-se neste estudo avaliar as características agronômicas, a composição químico-bromatológica e a digestibilidade de 11 cultivares de milho (Zea mays) colhido em duas alturas de corte. As cultivares D 766, D 657, D 1000, P 3021, P 3041, C 805, C 333, AG 5011, FO 01, CO 9621 e BR 205 foram avaliadas quando colhidas 5 cm acima do solo (baixa) e 5 cm abaixo da inserção da primeira espiga (alta). O experimento foi delineado como blocos casualizados, com três repetições, arranjados em esquema fatorial 11 x 2. Os cultivares apresentaram produções semelhantes de matéria seca de forragem e de grãos. As porcentagens das frações colmo, folha, palha, sabugo e grão diferiram entre os cultivares, assim como os teores de matéria seca da planta inteira no momento da colheita. Considerando a planta inteira, apenas os teores de energia bruta, nitrogênio da fração fibra em detergente neutro e a digestibilidade in vitro da fibra em detergente neutro e detergente ácido não diferiram entre os cultivares. O aumento da altura de corte melhorou a qualidade da forragem, devido à redução das frações colmo e folha e dos teores dos constituintes da parede celular

Balanço de nutrientes e perfil de ácidos graxos do leite de vacas leiteiras no terço médio e lactação suplementadas como monensina

The aim of this study was to evaluate the nutrients balance and milk fatty acids profile of dairy cows supplemented with monensin. Twelve Brazilian Holstein dairy cows were distributed into four balanced 3x3 Latin squares, and fed with the following diets: control (C), basal diet without addition of monensin, monensin 24 (M24), addition of 24mg/kg DM of monensin, and monensin 48 (M48), addition of 48mg/kg DM. The experimental diets influenced the efficiency of net energy of lactation utilization. A quadratic effect was observed for the energy balance. It was observed effect of diets on nitrogen balance. It was observed effect of monensin in the milk yield, composition and in the milk fatty acids profile. Monensin in diets of dairy cows in mid lactation, using corn silage, improved the nutrients balance and milk fatty acid profile with 24mg/kg DM

Novos desafios da pesquisa em nutrição e produção animal.

Os organizadores autorizam a reprodução total ou parcial deste trabalho, para qualquer meio convencional ou eletrônico, para fins de estudo e pesquisa, desde que citada a fonte

Evaluation of the Milk Fatty Acid Profile from Mediterranean Buffalo Cows in the First Eight Weeks of Lactation

The aim of this study was to evaluate the fatty acid composition of buffalo milk in the first eight weeks oflactation. It was used 18 cows multiparous Buffaloes of Mediterranean race, the data collection starting four weeksbefore of the calving provided by the 8th week of lactation. The animals were mechanically milked once daily in themorning. The milk samples used for composition analysis were collected weekly from parturition to eight weeks oflactation. There was effect of weeks during the transition period and early lactation for fat yield (kg/day) and for bodyweight of the buffalo cows in lactation (kg).There was effect of weeks of lactation on the fatty acid composition of milkfat.Variations in levels of unsaturated fatty acids of milk fat of buffaloes are similar to those found in dairy cows of thepartum to eighth week of lactation

Nitrogen balance and milk composition of dairy cows fed urea and soybean meal and two protein levels using sugar cane based diets

O objetivo deste trabalho foi avaliar o efeito de dois teores de proteína bruta (PB) (baixa: 142 g de PB/kg de MS e alta: 156 g de PB/kg de MS) e de duas fontes nitrogenadas (farelo de soja e ureia) na dieta de vacas leiteiras, alimentadas com cana-de-açúcar como volumoso sobre a síntese de proteína microbiana, composição da fração nitrogenada do leite, balanço de nitrogênio (N) e parâmetros sanguíneos. Foram utilizadas 12 vacas Holandesas com produção média de 22,0 ± 2,3 kg leite/dia, no terço final de lactação (235 ± 40 dias em lactação), agrupadas em três quadrados latinos balanceados e contemporâneos 4x4, com período experimental de 21 dias, dos quais 14 para adaptação as dietas e os demais para coleta de amostras. A excreção total de urina (L/dia), o NUL e a ureia sanguínea foram maiores para as dietas com alta PB, independentemente da fonte nitrogenada. A eficiência de utilização do N foi maior para as vacas alimentadas com dietas com baixa PB. Vacas no terço final da lactação podem ser alimentadas com dietas com teores reduzidos de PB, independentemente de a fonte nitrogenada ser farelo de soja ou ureia, sem influenciar a síntese de proteína microbiana, a composição da fração nitrogenada do leite e obter maior eficiência de utilização do N da dieta.The aim of the study was to evaluate the effect of feeding two levels of crude protein (CP) (low: 142 g CP/kg DM; and high: 156 g CP/kg DM) and two nitrogen sources (soybean meal and urea) to dairy cows using sugar cane as forage on microbial protein synthesis, the composition of the milk nitrogen fraction, nitrogen (N) balance and blood parameters. Twelve Holstein cows with an average milk yield of 22.0 ± 2.3 kg/day, and with 235 ± 40 days in milk were included in this study. The animals were grouped into three balanced and contemporary 4x4 Latin squares for an experimental period of 21 days. On the 15th day of each period, milk and urine samples were collected for microbial protein synthesis determination. Total excretion of urine (L/day), milk urea nitrogen (MUN) and blood urea were higher for the diets with high CP, regardless of the nitrogen source. Nitrogen efficiency was higher for cows fed diets with low CP. Cows in the final third of lactation can be fed diets with reduced CP levels, regardless of the nitrogen source, soybean meal or urea, without influencing the synthesis of microbial protein or the composition of the nitrogen fraction of milk