José Esler de Freitas Júnior

Utilização de óleo de soja em rações para vacas leiteiras no período de transição: consumo, produção e composição do leite

O objetivo neste estudo foi avaliar o desempenho produtivo de vacas leiteiras sob suplementacao com oleo de soja durante o periodo de transicao. Foram utilizadas 20 vacas da raca Holandesa, multiparas e gestantes, distribuidas aleatoriamente em duas racoes: controle, com 2,5% de extrato etereo (EE) na materia seca (MS); e gordura, com adicao de 3,0% de oleo de soja e 5,5% de EE na MS. Os valores medios de consumo de MS e nutrientes nao diferiram no periodo pre e pos-parto nas vacas das dietas controle e com oleo de soja, exceto no maior consumo de EE, em decorrencia da maior concentracao desse nutriente na dieta com oleo. Em virtude da maior densidade energetica da racao com oleo de soja, as vacas apresentaram maior consumo de nutrientes digestiveis totais e energia liquida no pos-parto. Nao foi observada alteracao nas producoes de leite e gordura, no entanto, observou-se reducao do teor de gordura do leite nas vacas da racao com oleo de soja em relacao aquelas da racao controle. As racoes utilizadas nao influenciaram o consumo, mas a dieta com oleo de soja aumentou a ingestao de energia liquida e melhorou o balanco de nutrientes no inicio da lactacao. Foi observado aumento nao-significativo (+ 2,53 kg/dia) na producao de leite das vacas da dieta com oleo de soja.

Productive performance and composition of milk protein fraction in dairy cows supplemented with fat sources.

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.

Organic and inorganic sources of zinc, copper and selenium in diets for dairy cows: intake, blood metabolic profile, milk yield and composition

The present study was carried out with the objective of evaluating the effects of feeding dairy cows with organic or inorganic sources of zinc (Zn), copper (Cu) and selenium (Se) on blood concentrations of these minerals, blood metabolic profiles, nutrient intake and milk yield and composition. Nineteen Holstein cows were selected and randomly assigned to two groups for receiving organic (n = 9) or inorganic (n = 10) sources of Zn, Cu and Se from 60 days before the expected date of calving to 80 days of lactation. Samples of feed, orts and milk were collected for analysis. Body condition score (BCS) was determined and blood samples were collected for analysis of Zn, Cu and Se concentrations, as well as for metabolic profile. Supplying organic or inorganic sources of Zn, Cu, and Se did not affect dry matter and nutrient intake, blood metabolic profile, milk yield and composition, plasma concentration of these minerals, and BCS or change the BCS in cows from 60 days before the expected date of calving to 80 days of lactation. An effect of time was observed on all feed intake variables, plasma concentrations of Zn and Se, milk yield, milk protein content, BCS and change in BCS.

Efeito da condição corporal ao parto sobre o desempenho produtivo de vacas mestiças Holandês × Zebu

Twenty-five crossbred Holstein-Zebu cows was used to evaluate the effect of body condition score at calving on milk yield and composition and evaluate the body reserves mobilization by variation of body condition score during the first 120 days of lactation. The cows were allocated in two classes according to the body condition score at calving (BCSC), using a scale from 1 (very thin) to 5 (very fat): class 1, cows with of BCSC > 3.25; and class 2, cows with BCSC <3.25. As expected the two classes of BCSC were significantly different at calving, showing mean values of 3.71 and 2.58 for class 1 and 2, respectively. From calving to 120 days of lactation cows of class 1 showed greater change in body condition score (CBCS) than cows of class 2 with mean cows, showed values of -0,57 and -,12 units of BCS for class 1 and 2, respectively. The body condition score at calving did not influence milk yield, but milk yield adjusted to 3.5% fat, fat percentage and production were different between cows of class 1 and 2. The crossbred cows Holstein-Zebu with a BCSC greater to 3.0 showed higher milk yield corrected to 3.5% fat and yield fat in this study.

Evaluation of corn cultivars harvested at two cutting heights for ensilage

Objetivou-se neste estudo avaliar as caracteristicas agronomicas, a composicao quimico-bromatologica 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 insercao da primeira espiga (alta). O experimento foi delineado como blocos casualizados, com tres repeticoes, arranjados em esquema fatorial 11 x 2. Os cultivares apresentaram producoes semelhantes de materia seca de forragem e de graos. As porcentagens das fracoes colmo, folha, palha, sabugo e grao diferiram entre os cultivares, assim como os teores de materia seca da planta inteira no momento da colheita. Considerando a planta inteira, apenas os teores de energia bruta, nitrogenio da fracao fibra em detergente neutro e a digestibilidade in vitro da fibra em detergente neutro e detergente acido nao diferiram entre os cultivares. O aumento da altura de corte melhorou a qualidade da forragem, devido a reducao das fracoes colmo e folha e dos teores dos constituintes da parede celular.

Parâmetros sanguíneos de vacas leiteiras suplementadas com diferentes fontes de gordura

This study was carried out to evaluate the use of different fat sources in dairy cows rations and its effects on dry matter intake, milk yield and composition, and blood parameter. Twelve Holstein cows were allocated in three balanced latin square 4x4, and fed with the following rations: 1) Control, with 2.5%; 2) Refined soybean oil; 3) Whole soybean; and 4), Calcium salts of fatty acids (Megalac-E). The concentrations of total cholesterol and lipoprotein low density (LDL) were higher (P<0.05) for cows that received rations with fat sources, which also causes increased (P<0.05) e concentration of high density lipoprotein (HDL). The concentrations of urea and blood urea nitrogen were similar among the rations, except for the diet containing calcium salts of fatty acids, which showed lower (P<0.05). The dry matter intake was lower (P<0.05) in cows that received calcium salts in the rations. The animals that received a diet containing whole soybeans as a source of fat had lower (P<0.05) yield milk when compared to other rations used. The use of fat sources in dairy cows rations influenced the blood parameters, especially for parameters related to lipidogram.

Fatty acid profile and composition of milk protein fraction in dairy cows fed long-chain unsaturated fatty acids during the transition period

The objective of this study was to evaluate the utilization of different sources of unsaturated long-chain fatty acids in diets for dairy cows during the transition period and early lactation on the milk fatty acid profile and composition of the protein fraction. Thirty-six Holstein cows were divided into three groups, fed the following diets: control (C); soybean oil (SO); and calcium salts of long-chain unsaturated fatty acids (CS). The milk samples utilized for analysis were obtained weekly from parturition to twelve weeks of lactation; each one of the samples originated from two daily milkings. Milk composition and total nitrogen, non-protein nitrogen and non-casein nitrogen levels were analyzed. The cows receiving the diet with calcium salts had lower concentrations of non-protein nitrogen (%CP) in milk compared with the animals fed the diet with soybean oil. There was a decrease in concentration of medium-chain fatty acids C12-C16, and a concomitant increase in concentrations of long-chain fatty acids >C18 in milk fat for the animals fed the diets CS and SO when compared with diet C. Soybean oil and CS diets increased milk-fat concentrations of the acids C18: 1 trans-11, C18: 2 cis-9, trans-11 and C18: 2 trans-10 cis-12 in relation to diet C. The utilization of sources of long-chain fatty acids in the diet of dairy cows increases the biological value of milk in early lactation due to higher concentrations of specific fatty acids such as CLA C18: 2cis-9, trans-11.

Lipid and selenium sources on fatty acid composition of intramuscular fat and muscle selenium concentration of Nellore steers

The objective of this study was to evaluate the effect of lipid and selenium sources in diets for finishing Nellore steers on the fatty acid composition and selenium concentration of the longissimus muscle. Fifty Nellore steers (body weight = 458±39 kg) were assigned to one of six dietary treatments: 1) diet containing sunflower seed and inorganic selenium; 2) sunflower seed and organic selenium; 3) whole cottonseed and inorganic selenium; 4) whole cottonseed and organic selenium; 5) soybeans and inorganic selenium; and 6) soybeans and organic selenium. Diets were formulated with the same amount of nitrogen and calories and supplied once daily to steers in collective pens, with three animals per pen, for 120 d. At the end of the trial, steers were slaughtered and samples of the longissimus muscle were collected for fatty acid and selenium analysis. Effect of selenium sources was detected for selenium concentration in the longissimus muscle. Organic selenium had higher concentrations in the meat compared with inorganic selenium. The total saturated, monounsaturated and polyunsaturated fatty acids did not differ between the sources of lipids and selenium. For selenium sources, no differences were observed between the concentrations of polyunsaturated fat. Also, no differences in C18:2 cis-9 trans-11 concentrations were noted; however, steers fed sunflower seed presented greater proportions of this fatty acid in the meat. The results indicated that the use of sunflower seed, cottonseed or soybeans and organic or inorganic selenium in feedlot diets to Nellore cattle does not alter the great part of the fatty acid profile of the longissimus muscle. However, the inclusion of sunflower seed in the diet increases the meat CLA cis-9, trans-11, which is desirable and beneficial for the health of consumers.

Digestion of feed fractions and intake of heifers fed hydrolyzed sugarcane stored for different periods

The objective of this study was to evaluate, in Nellore heifers, intake and digestibility of hydrolyzed sugarcane stored for different periods. The experimental design used was a 4 × 4 Latin square, four diets, four Nellore heifers with ruminal cannulas (initial body weight 285.4±23.08 kg and average initial age 14 months) and four periods of 21 days. The diets were composed by fresh sugarcane (time zero) or hydrolyzed sugarcane with addition of 0.5% of hydrated lime, stored for 24, 48 or 72 hours, as the unique forage. Intake and digestibility of feed fractions, nitrogen balance, microbial synthesis efficiency, total number of ruminal protozoans and ammoniacal nitrogen did not significantly change by storing sugarcane with addition of 0.5% of hydrated lime. Sugarcane pH varied quadratically for storage time, with maximum pH of 7.02 after 24 hours from lime addition. Ruminal liquid pH values were higher for heifers fed fresh sugarcane, in comparison with those fed hydrolyzed sugarcane. Sugarcane treated with 0.5% of hydrated lime stored for up to 72 hours does not change ruminal digestion to alter the amount of feed consumed by pubescent Nellore heifers. Thus, lime is a viable technology, once it allows long-duration storage and bee control on treated forage, which contributes to animal feeding logistics.

Fatty acid composition of the longissimus dorsi muscle in crossbred steers fed different sources of fatty acids

The objective of this study was to evaluate the fatty acid composition of the longissimus dorsi muscle in carcasses of ¾ Bos taurus taurus ¼ Bos taurus indicus steers fed different sources of fatty acids. Thirty-six steers aged 14 months, with a mean live weight of 320 kg, were fed the following diets for 96 days: 1) control diet, containing no supplemental fat source; 2) CaSFA, diet containing 50 g calcium salts of fatty acids per kg total dry matter; 3) CS diet, containing 210 g cottonseed per kg total dry matter. The fatty acid composition of the longissimus dorsi muscle was determined by gas chromatography. No difference in slaughter weight, carcass weight, backfat thickness, or longissimus dorsi muscle area was observed between animals receiving the diets CaSFA and CS. Animals consuming the two fat-supplemented diets presented higher concentrations of oleic (C18:1), palmitic (C16:0) and stearic (C18:0) acids, corresponding to an average 80.76% of total fatty acids, and higher concentrations of vaccenic acid (C18:1 t11) in the muscle when compared with the control group. Supplementation of the diet of feedlot crossbred steers with CaSFA or cottonseed did not promote significant alterations in the lipid composition of the longissimus dorsi muscle.