&lt;b&gt;Urea and salt as supplementary diet for crossbreed milk cows

Gomes

2020

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The objective was to evaluate the partial substitution of sugarcane treated with urea by elephant grass in the feeding of crossbred cows in lactation. Eight crossbred cows (Holstein x Gyr) were used, with 474 kg of body weight (standard deviation = 46.15 kg) and 8.15 kg of milk per day. The animals were housed in individual stalls, distributed in two 4 x 4 Latin squares, and the treatments were: sugar cane; sugar cane corrected with 0.5% of urea and ammonium sulfate (9:1); 75% of sugar cane + 25% of elephant grass and 50% of sugarcane + 50% of elephant grass, based on natural matter. In addition to the treatments, it was provided water and mineral salt ad libitum and 3 kg of concentrate supplement (24% crude protein), based on corn meal and soybean meal, supplied in two portions during the morning and afternoon milking. There was a treatment effect on the intake and digestibility of dry matter and nutrients, except for non-fibrous carbohydrate intake, and there was no effect on milk production and composition. It can be concluded that the substitution of sugarcane by elephantgrass (25 and 50%) increases the intake and decreases the digestibility of DM and OM, without affecting milk production, when the cows are supplemented with 3 kg of concentrate, containing 24% of protein per day.

Section: Resultssupporting

confidence: 75%

Sugarcane with Elephant grass replacing sugarcane with urea in the diet of crossbred dairy cows1

Gomes

2020

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“…Therefore, in the present study, urea from nitrogen salt was not efficiently used in ruminal microbial protein synthesis, which caused a reduced nitrogen balance, probably due to the energy deficit of tropical pasture. Accordingly, Teixeira et al (2015) also found high values of urinary urea nitrogen in dairy cows consuming mineral supplements containing 20% urea (621 to 764 mg dL -1 ). On the other hand, when the concentrate was used in a higher level, the input of energy favored the synthesis of ruminal microbial protein, justifying the increase in total nitrogen excreted in milk.…”

Section: Resultsmentioning

confidence: 82%

“…In the present study, values varied between 13.3 and 14.3 mg dL -1 (Table 2), within the range considered desirable, and without treatment effect. On the other hand, Teixeira et al (2015) found high values of SUN and MUN in dairy cows consuming mineral supplements containing 20% urea (18 to 20 and 20 to 22 mg dL -1 , respectively); and Souza Júnior et al (2016) found high NUS values in dairy cow diets with 16 versus 12% crude protein (27.9 vs 15.0 mg dL -1 ).…”

Section: Resultsmentioning

confidence: 98%

<b>Nitrogen compounds balance and microbial protein synthesis in supplemented crossbred dairy cows in pasture

Gutierrez

et al. 2018

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The objective this work was to evaluate the supplementation of cows on Brachiaria decumbens pasture during the rainy-dry transition. Eight 1/2 Holstein/Zebu cows (497 ± 50 kg) were distributed in two 4 x 4 Latin squares, with 2 x 2 factorial treatments (100% mineral salt versus nitrogen salt containing 25:25:50% urea: corn: mineral salt, and 1.5 versus 3.0 kg d-1 concentrate per cow). The experiment lasted 56 days, divided into four periods of 14 days, the last seven days for data collection. No interaction effect (p > 0.05) was detected between the supplement and the different levels of concentrate for any of the evaluated variables. No effect (p > 0.05) of supplement or concentrate level was observed on urinary excretions of purine derivatives, microbial nitrogen compounds and microbial efficiency. Nitrogen salt increased (p < 0.05) nitrogen intake and increased urinary nitrogen excretion, leading to a reduced nitrogen balance, while the higher concentrate level increased (p < 0.05) nitrogen intake and the total amount of nitrogen excreted in milk. Therefore, it is recommended, for crossbred cows in the rainy-dry transition period, the supply of 1.5 kg d-1 concentrate during milking, using only mineral salt instead of nitrogen salt at will on pasture.

“…Nellore cows have an increase in fat and protein rates as gene fractions of Holstein strain decrease (Teixeira et al, 2015). In current analysis, fat percentage averaged 4.73%, but mean fat percentage in the milk of pure Holstein cows was 3.66% (Aikman, Reynolds, Beever, 2007).…”

Section: Resultsmentioning

confidence: 99%

<b>Protected fat and variable level of protein in diets of crossbreed cows in early lactation

Júnior

et al. 2016

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ABSTRACT. Current study evaluated the inclusion of protected fat and different levels of crude protein (CP) in the diet of crossbreed cows in early lactation. Twelve cows were distributed in a 4 x 4 factorial design, with four treatments (12 or 16% CP, with or without MEGALAC-E ® ). Statistical analyzes with ANOVA and Pearson's linear correlation procedures were performed. Protected fat did not affect intake of dry matter (DM) and organic matter (OM) (p > 0.05). Increased CP raised consumption of CP and EE and decreased the non-fiber carbohydrates (NFC; p <0.05). Protected fat increased (p <0.05) the digestibility of DM, OM, CP and ashes in the lower protein content. CP increase raised the level of blood and urinary urea (p < 0.05). There was no difference (p > 0.05) on milk yield and composition due to protected fat or CP rates. Since the inclusion of protected fat and higher content of CP (16%) in the diet did not benefit the production and composition of milk in crossbreed cows, diets with 12% CP without the inclusion of protected fat are recommended.Keywords: concentrate, dietary protein, digestibility, intake, lipid supplementation, milk yield.Gordura protegida e nível variável de proteína em dietas para vacas mestiças no terço inicial da lactação RESUMO. O objetivo desse estudo foi avaliar a inclusão de gordura protegida e de diferentes níveis de PB, na dieta para vacas mestiças, no início da lactação. Foram utilizadas 12 vacas, distribuídas em quadrados latinos 4 x 4 e quatro tratamentos (12 ou 16% de PB, com ou sem MEGALAC-E ® ). Análises estatísticas foram realizadas utilizando Anova e correlações lineares de Pearson. A gordura protegida não influenciou o consumo de MS e MO (p > 0,05). O aumento de PB elevou o consumo de PB e EE e diminuiu o de carboidratos não fibrosos (CNF; P<0,05). A gordura protegida aumentou (p < 0,05) a digestibilidade da MS, MO, PB e cinzas no menor teor de proteína. O aumento de PB elevou os níveis de ureia sanguínea e urinária (p < 0,05). Não houve diferença (p > 0,05) na produção e composição do leite em função da gordura protegida ou do teor de PB. A inclusão de gordura protegida e o maior teor de PB (16%) na dieta não resultaram em benefícios na produção e composição do leite de vacas mestiças, portanto recomenda-se utilizar dietas contendo 12% de PB, sem a inclusão de gordura protegida.Palavras-chave: concentrado, proteína dietética, digestibilidade, consumo, suplementação lipídica, produção de leite.