Milk fatty acid profile from grazing buffaloes fed a blend of soybean and linseed oils / Perfil de ácidos graxos do leite de búfalas a pasto recebendo uma mistura de óleo de soja e linhaça na dieta

The aim of the study was to examine the changes in milk fatty acid (FA) profile of grazing buffaloes fed either low (L, 276g/d) or high (H, 572g/d) doses of a blend (70:30, wt/wt) of soybean and linseed oils. Fourteen multiparous Mediterranean buffaloes grazing on a native pasture were fed 4 kg/day of a commercial concentrate containing no supplemental oil over a pre-experimental period of ten days. The baseline milk production and composition and milk FA profile were measured over the last three days. After this pre-experimental period the animals received the same concentrate added with either the L or H oil doses for 26 additional days. Milk yield (g/animal/day) did not differ at the start (1776 ± 522 and 1662 ± 291 for L and H, respectively, P<0.622) or at the end of the trial (4590 ± 991 and 4847 ± 447 in L and H, respectively, P<0.543). Baseline milk fat content (g/kg) averaged 77.1 (±20.5) in L and 74.3 (±9.9) in H (P<0.10) and was reduced (P<0.031) to 60.7 (±23.6) and 49.4 (±11.2) (P<0.0031) respectively after L and H with no differences between treatments (P<0.277). Baseline milk protein content (L=43.2 ± 3.4 and H= 44.3 ± 6.9g/kg) increased after oil supplementation (P<0.0001) in both L (73.2 ± 6.0g/kg) and H (68.4 ± 4.9g/kg) without differences between oil doses (P<0.123). Milk fat content of 14:0 decreased after oil supplementation only in the H treatment (5.29 to 4.03, P<0.007) whereas that of 16:0 was reduced (P<0.001) at both L (24.49 to 19.75g/100g FA) and H (25.92 to 19.17g/100g FA) doses. The reduction of total content of 12:0 to 16:0 was higher (P<0.052) in H (32.02 to 23.93g/100g FA) than L (30.17 to 25.45g/100g FA). Vaccenic acid content increased (P<0.001) from 5.70 to 13.24g/100g FA in L and from 5.25 to 16.77 in H, with higher results in the in H treatment (P<0.001). Baseline rumenic acid was sharply increased (P<0.001) in L (1.80 to 4.09g/100g FA, +127%) and H (1.60 to 4.61g/100g FA, +187%) with no differences between...

O objetivo do presente estudo foi avaliar as mudanças no perfil de ácidos graxos do leite de búfalas leiteiras recebendo baixas (B, 276g/d) ou altas (A, 572g/d) doses de uma mistura de óleos de soja e linhaça (70:30, peso/peso) na dieta. Quatorze búfalas multíparas da raça Mediterrânea, mantidas em pastagens nativas, receberam 4kg/dia de um concentrado comercial sem adição de óleo (pré-tratamento) ao longo de umperíodopré-experimental de 10 dias. A produção de leiteindividual e amostras de leite foram coletadas individualmente para determinação dos valores basais de composição e perfil de ácidos graxos do leite nos últimos trêsdias. Após este período, os animais receberam o mesmo concentrado adicionado deBou Apor 26 dias. A produção de leite (g/animal/dia) não diferiu no início (1776 ± 522 e 1662 ± 291para B e A, respectivamente (P<0,622) e no final do período experimental(4590 ±991e4847 ± 447 para LeH, respectivamente, P<0,543). O teor de gordura do leite (g/100g) apresentou valores médios de 77,1(±20,5)paraBe74,3 (±9,9)paraA(P<0,10) durante o período pré-tratamento,mas foi reduzido (P<0,03) após o fornecimento das dietas com óleo para 60,7 (± 23,6) e 49,4 (± 11,2), respectivamente para B e A, não havendo diferenças entre tratamentos (P<0,277). Os teores basais de proteína do leite (B=43,2 ± 3,4 e A=44,3 ± 6,9g/kg) aumentaram após a suplementação com óleo (P<0,0001) em ambos B (73,2 ± 6,0g/kg) e A (68,4 ± 4,9g/kg), não ocorrendo diferenças entre tratamentos (P<0,123). O teor médio basal de 14:0 na gordura do leite (4,76g/100g AG) foi reduzido após a suplementação da dieta com óleo somente no tratamento A (5,29 para 4,03, P<0,007). O teor de 16:0 na gordura do leite foi reduzido (P<0,001) nos tratamentos B (24,49 para 19,75g/100g AG) e A (25,92 para 19,17g/100g AG). A redução nos teores de 12:0+14:0+16:0 na gordura do leite foi maior (P<0,052) em A (32,02 para 23,93g/100g AG) do que em B (30,17 para 25,45g/100g AG). O teor de ácido vacênico (AV)...

Partial replacement of corn grain by hydrogenated oil in grazing dairy cows in early lactation.

Thirty-six grazing dairy cows were used to determine milk production and composition, and dry matter and energy intake when corn grain was partially replaced by hydrogenated oil in the concentrate. Four additional cows, each fitted with a ruminal cannula, were used in a crossover design to evaluate effects of supplemental fat on rumen environment and pasture digestion. All cows grazed mixed pastures with an herbage allowance of 30 kg dry matter/cow per day. The control group was fed a concentrate containing corn grain (4.49 kg dry matter/cow per day) and fishmeal (0.37 kg dry matter/cow per day), whereas the other group (fat) received a concentrate containing corn grain (2.87 kg dry matter/cow per day), fishmeal (0.37 kg dry matter/cow per day) and fat (0.7 kg dry matter/cow per day). The fat was obtained by hydrogenation of vegetable oils (melting point 58 to 60 degrees C, 30.3% C16:0, 34.9% C18:0, 21.8% C18:1, 3.3% C18:2). Supplemental fat increased milk production (control = 23.7 vs. fat = 25.0 kg/cow per day), fat-corrected milk (control = 22.5 vs. fat = 24.5 kg/cow per day), milk fat content (control = 3.64% vs. fat = 3.86%) and yields of milk fat (control = 0.86 vs. fat = 0.97 kg/cow per day) and protein (control = 0.74 vs. fat = 0.78 kg/cow per day). Milk percentages of protein, lactose, casein, cholesterol, and urea nitrogen were not affected. Pasture DMI and total DMI of pasture and concentrate and estimated energy intake were unchanged. No differences in loss of body weight or body condition score were detected. Plasma concentrations of nonesterified fatty acids, somatotropin, insulin, and insulin-like growth factor were not affected by supplemental fat. Concentrations of plasma triglyceride and total cholesterol were increased by supplemented fat, and no changes in plasma glucose and urea nitrogen were observed. The acetate-to-propionate ratio was higher in rumen fluid of cows that consumed fat (fat = 3.39 vs. control = 3.27). In situ pasture NDF degradation was not affected. The partial replacement of corn grain with fat improved the productive performance of early-lactation cows grazing spring pastures. No negative effects of supplemental fat on ruminal fiber digestion were detected.

Milk fatty acid composition of cows fed a total mixed ration or pasture plus concentrates replacing corn with fat.

Thirty-one Holstein cows (six ruminally cannulated) were used to evaluate milk fatty acids (FA) composition and conjugated linoleic acid (CLA) content on three dietary treatments: 1) total mixed rations (TMR), 2) pasture (Avena sativa L.) plus 6.7 kg DM/d of corn-based concentrate (PCorn), and 3) pasture plus PCorn with 0.8 kg DM/d of Ca salts of unsaturated FA replacing 1.9 kg DM/d of corn (PFat). No differences were found in total (22.4 kg/d) or pasture (18.5 kg/d) dry matter intake, ruminal pH, or total volatile fatty acids concentrations. Fat supplementation did not affect pasture neutral detergent fiber digestion. Milk production did not differ among treatments (19.9 kg/d) but 4% fat-corrected milk was lower for cows fed the PFat compared to cows fed the TMR (16.1 vs. 19.5 kg/d) primarily because of the lower milk fat percentage (2.56 vs. 3.91%). Milk protein concentration was higher for cows fed the TMR than those on both pasture treatments (3.70 vs. 3.45%). Milk from the cows fed the PCorn had a lower content of short- (11.9 vs. 10.4 g/100 g) and medium-chain (56.5 vs. 47.6 g/100 g) FA, and a higher C18:3 percentage (0.07 vs. 0.57 g/100 g) compared with TMR-fed. Cows fed the PFat had the lowest content of short- (8.85 g/100 g) and medium-chain (41.0 g/100 g) FA, and the highest of long-chain FA (51.4 g/100 g). The CLA content was higher for cows in PCorn treatment (1.12 g/100 g FA) compared with cows fed the TMR (0.41 g/100 g FA), whereas the cows fed the PFat had the highest content (1.91 g/100 g FA). Pasture-based diets increased the concentrations of long-chain unsaturated FA and CLA in milk fat. The partial replacement of corn grain by Ca salts of unsaturated FA in grazing cows accentuated these changes. However, those changes in milk FA composition were related to a depression in milk fat.

Supplementation with partially hydrogenated oil in grazing dairy cows in early lactation.

Effects of partially hydrogenated oil on performance, loss of body weight and body condition score, and blood metabolite and hormone concentrations were evaluated in 37 multiparous Holstein cows in grazing conditions during the first 100 d of lactation. Six additional Holstein cows, each fitted with a ruminal cannula, were allocated to a replicated 3 x 3 Latin square to evaluate effects of supplemental fat on rumen environment and pasture digestion. All cows grazed mixed pastures based on alfalfa (Medicago sativa) and orchardgrass (Dactylis glomerata L.) and received 5.4 kg/d of a basal concentrate to which 0, 0.5, or 1 kg/cow per day of partially hydrogenated oil (melting point 58 to 60 degrees C) containing 30.3, 34.9, 21.8, and 3.3% of C16:0, C18:0, C18:1, and C182, respectively, was added. Feeding 1 kg/d of supplemental fat increased fat-corrected milk from 23.4 to 26.3 kg/d, milk fat content from 3.44 to 3.78%, and milk fat yield from 0.87 to 1.03 kg/d compared to control. Milk protein percentage and yield were not affected. Cows fed 1 kg/d of fat increased the content and yield of C16:0 and C18:0 in milk compared with cows fed no added oil. Dry matter intake (DMI) from pasture decreased from 17.8 kg/d for control cows to 13.6 kg/d for cows fed 1 kg of oil, whereas DMI from concentrate was higher for cows fed 1 kg/d of fat (6.0 kg/d) than for controls (5.2 kg/d). Supplemental fat did not affect total dry matter or estimated energy intake and did not change losses of body weight or body condition scores. Plasma concentrations of nonesterified fatty acids, insulin, somatotrophin, and insulin-like growth factor-I did not differ among treatments. Concentration of plasma triglycerides was lowered from 318.5 to 271.2 mg/dl, whereas plasma cholesterol was elevated from 185.0 to 235.8 mg/dl in cows receiving 1 kg/d of supplemental fat compared with controls. Responses to lipolytic or insulin challenges were not affected by feeding oil. Supplemental fat did not affect the digestion of pasture fiber. The addition of energy in the form of partially hydrogenated fat to early lactation dairy cows fed primarily on pasture increased the yield of fat-corrected milk and milk fat content when it represented about 11% of the total metabolizable energy requirement of cows, without affecting milk protein content. The partial hydrogenation of a byproduct of the oil industry apparently prevented detrimental effects of fat supplementation on ruminal digestion.

Undegradable protein supplementation to early-lactation dairy cows in grazing conditions.

To determine the production responses to rumen undegradable protein (RUP) feeding in grazing conditions, we fed 18 multiparous Holstein cows concentrates containing either soybean meal (SBM) or blood meal (BM) during the first 8 wk of lactation. One cow from the SBM treatment was removed because of mastitis. Six additional dairy cows in late lactation fitted with ruminal cannula were used to evaluate the rumen environment and the in situ crude protein (CP) degradability of concentrates. On a dry matter (DM) basis, concentrates contained SBM (33%) or BM (13%), corn grain (64 and 84% for SBM and BM, respectively) and a mineral-vitamin complex (3%). Concentrates were offered at a rate of 6.6 kg/d per cow and herbage allowance averaged 31 kg/d of DM per cow. The BM reduced ruminal ammonia-N levels and had no effect on ruminal pH and molar volatile fatty acid concentration. The degradable fraction (63.59 vs. 22.46%) and the rate of disappearance of the CP (9.68 vs. 1.69%/h) were greater for the SBM compared with the BM concentrate. Cows fed the BM concentrate produced more milk (29.3 vs. 24.9 kg/d) and more milk protein (0.85 vs. 0.74 kg/d) than did those fed the SBM concentrate. Milk fat yield and percentages of milk fat, lactose and protein were not affected. Forage DMI was increased by BM (17.19 vs. 13.17 kg/d per cow). The in vivo responsiveness to lipolytic stimuli were increased by BM but enhanced body weight loss or higher plasma nonesterified fatty acids concentration were not observed. Results indicated that a concentrate with a high RUP content increased milk and milk protein yields when spring pasture was the sole forage. The highest milk yield was more likely caused by increased DM than by enhanced body lipid mobilization.

Fishmeal supplementation to grazing dairy cows in early lactation.

Our objectives were to determine if grazing dairy cows would respond to fishmeal supplementation and to determine if responses could be explained by stimulation of adipose tissue lipolysis. Thirty-four multiparous Holstein cows (25+/-11 DIM) were supplemented with isonitrogenous concentrates containing either fishmeal or pelleted sunflower meal. On a dry matter (DM) basis, concentrates contained fishmeal (14.5%) or sunflower meal (24.2%), corn grain (55.6% and 50.6%), wheat bran (26.7% and 22%), a mineral-vitamin complex (2.9%) and a flavoring agent (0.3%). Concentrates were consumed at a rate of 5 kg/cow per day. Herbage allowance averaged 49.8+/-6.1 kg of DM/cow per d. Milk (26.8 vs. 25.2 kg/d), fat-corrected milk (23.9 vs. 22.2 kg/d) and milk protein yields (0.90 vs. 0.81 kg/d) were increased by fishmeal. Milk protein percentage was similar among treatments. Milk fat yield and milk and plasma urea nitrogen tended to be higher in cows fed fishmeal. Plasma glucose and nonesterified fatty acids concentrations and differences in concentrations between jugular and mammary veins were increased by fishmeal. The in vivo lipolytic response to a beta-adrenergic agent or the antilipolytic + hypoglycemic action of insulin were not affected. The higher milk production observed with fishmeal can be explained by the quantity and quality of the absorbed protein, higher glucose availability to the mammary gland, and increased lipid mobilization without change in responsiveness of the adipose tissue to lipolytic stimuli.