Milk Fatty-Acid Profile after Feeding Increasing Doses of a Mixture of Soybean and Linseed Oils to Pasture Dairy Cows

The goal was to determine the effect of growing intake of a mixture (75:25) of soybean (SoOi) and linseed (LiOi) oils on milk production and composition and milk fatty-acid (MF-A) profile in grazing dairy cows. Twenty-four Holstein cows were assigned to 4 treatments in a completely randomized design with three weeks of adaptation to oil doses and one week of experimental measurements. On a dry matter (DM) basis, cows were fed pasture (63%), energy concentrate (37%) and the SO-LO oil mixture at zero (Tr0%), 2% (Tr2%), 4% (Tr4%) and 6% (Tr6%) of total DM intake equivalent to 0, 0.36, 0.72 and 1.08 kg/cow/day of the oil mixture. The oil mixture was manually mixed-up to the concentrate (7.04 kg DM cow/day) and supplied by halves during each milking time without refusals. Pasture (P = 0.49) and total DM intakes (P = 0.31) were similar between treatments averaging 11.27 and 18.85 kg DM cow-1 day-1 respectively. Milk output (22.71 kg/cow/day) was not affected (P = 0.46). Milk fat content reduced linearly (P  0.05) from T2% (3.37) but was upper (P < 0.05) in Tr4% (4.41) and Tr6% (4.63) remaining under the recommended value of 5:1. Taken together the results suggest that feeding a blend (75:25; SoOi:LiOi) of SiOi an LiOi oils at 4% of total DM intake to pasture dairy cows maximize the milk RA content with a concomitant decrease in the hypercholesterolemic MF-A of milk maintaining a beneficial for health Ω6/Ω3 ratio with low levels of the detrimental trans-9 C18:1 and trans-10 C18:1

Effects of feeding combinations of soybean and linseed oils on productive performance and milk fatty acid profile in grazing dairy cows

Thirty-six grazing dairy cows were used to determine the effect of combinations of soybean (SO), and linseed (LO) oils on milk production, composition and milk fatty acid (FA) profile. Treatments were a basal control diet (56% pasture, 44% concentrate) or the control diet supplemented with oils at 4% of estimated total dry matter (DM) intake. Oils were manually mixed to the concentrate in pure forms (SO100 or LO100) or in blends (%w/w) at SO75 - LO25, SO50 - LO50 and SO25 - LO75. Concentrate and oils were thoroughly consumed. Pasture intake (kg DM/cow·day) was 9.27 in control and decreased (p < 0.05) in SO25 - LO75 (8.09) and LO100 (8.98). Total DM intake (kg/cow·day) in control (16.47) increased (p < 0.05) to 17.04 in SO100 and 17.20 in SO75. Yield of fat corrected milk (4% FCM) averaged 20.73 kg in control resulting higher in SO75 (23.73 kg). Milk fat content (g/100g) in control averaged 3.40 and decreased to 2.79 in SO50-LO50 and to 3.06 in SO25 - LO75 treatments. Milk protein content was not affected and milk protein yield increased in SO100 (11%) and SO75 - LO25 (21%) over Control (0.729 kg/cow·day). Milk basal (Control) content (g/100g FA) of C12:0 (2.58), C14:0 (10.21) and C16:0 (25.69) was reduced (p < 0.05) to 1.64, 6.82 and 19.70 respectively in oil supplemented cows. Basal content of C12:0 to C16:0 averaged 38.48 g/100g FA and decreased (27.4%) after oil intake. Basal trans-10 C18:1 (0.46 g/100g FA) increased (p < 0.01) in SO100 (1.48) and SO50-LO50 (1.80). Basal level (g/100g FA) of vaccenic acid (trans-11 C18:1, VA) averaged 3.49 and increased (135%) after oil intake with maximum values observed in LO100 (8.17) and SO50 - LO50 (9.20). Rumenic acid (cis-9, trans-11 C18:2, RA) level (g/100g FA) in milk from Control cows (1.56) increased (p < 0.05) to 3.03 (SO100), 3.21 (SO75 - LO25), 3.24 (SO50 - LO50), 2.33 (SO25 - LO75) and 2.96 (LO100). Results obtained confirmed a great milk fat plasticity in response to PUFA feeding in grazing dairy cows which constitutes a very effective and easy tool in order to improve the healthy value of milk with a potential benefit to the consumer’s health. A net or conclusive response pattern over parameters that improve the healthy value of milk to soybean and linseed oils and their blends was not clearly detected. Taken together, the results suggest some advantage for the SO75:LO25 blend considering the relative costs of both oils, the positive effects on milk, fat and protein yields, the lower hypercholesterolemic FA content of milk and the increase in VA and RA content while maintaining a healthy n - 6/n - 3 ratio and very low levels of the detrimental trans-9 C18:1 and trans-10 C18:1 FA.Fil: Antonacci, Liliana. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce. Area de Producción Animal; ArgentinaFil: Gagliostro, Gerardo Antonio. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce. Area de Producción Animal; ArgentinaFil: Cano, Adriana Virginia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce. Area de Producción Animal; ArgentinaFil: Bernal, Claudio Adrián. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biologicas; Argentin

Milk Yield and Composition and Pasture Ruminal Digestion in Grazing Dairy Cows Receiving Three Levels of Energy Concentrate Supplementation

The objective of the experiment was to determine the effect of feeding three levels (T3.5, T7.0 and T10.5) of energy concentrate (3.5, 7.0 and 10.5 kg cow-1 day-1) on total dry matter (DM) and energy intakes, milk yield and composition, nutritional value of milk and rumen pasture neutral detergent fiber (NDF) digestion in grazing dairy cows. Twenty-one multiparous Holstein cows in early lactation (70.2 ± 13 days postpartum) producing 37.1 (±4.7) kg of milk were assigned to a 3 treatments (7 cows/treatment) × 3 periods Latin square design. Parameters of ruminal environment and pasture NDF degradation were obtained using 3 additional cows of the same breed fitted with rumen cannulae. On a wet basis, concentrate was composed by corn grain (68%), soybean meal (22%), wheat bran (8%) and a vitamin-mineral nucleus with monensin. Pasture (Medicago sativa, sp) was used in a rotational grazing system with an herbage allowance of 30 kg DM cow-1 d-1. Yield (kg cow-1 d-1) of fat corrected milk (4% FCM) resulted higher (p < 0.05) in T7.0 (29.0) compared to T3.5 (26.8) but similar to T10.5 (30.2). Milk and protein yields were linearly increased (p < 0.01) by concentrate intake. Milk fat (3.13 g/100g) and total solid contents (11.79 g/100g) did not differ whereas milk protein (p < 0.03) and casein (p < 0.01) levels (g/100g) increased linearly from 3.05 to 3.10 (protein) and from 2.42 to 2.47 (casein). Pasture intake decreased but total DM and energy consumption were enhanced showing addition effects after concentrate feeding. Body weight (BW) loss and plasmatic levels of non esterified fatty acids (NEFA) decreased with concentrate intake. Circulating levels of insulin-like growth factor-I (IGF-I) were higher (p < 0.05) in T10.5 while those of glucose, plasma urea nitrogen, insulin and somatotrophin were not affected. Ruminal pH and acetate concentration resulted lower (p < 0.05) in T10.5 when compared to T3.5. The acetate:propionate ratio decreased (p < 0.01) from 4.25 in T3.5 to 3.08 in T10.5 and ruminal ammonia nitrogen levels tended (p < 0.07) to be lower as concentrate intake increased. Kinetics parameters of NDF degradation remained unchanged. The potential hypercholesterolemic fatty acids (FA) of milk (C12:0 to C16:0.) remained unchanged as concentrate intake increased. Milk content of linolenic acid decreased and the n-6:n-3 ratio increased with concentrate intake from 1.56 (T3.5) to 2.57 (T10.5) remaining below the recommended values for human health (<4:1). Milk content of antioxidant vitamins was not significantly altered even when pasture DM intake fall in T10.5 compared to T3.5. Increased consumption of a starch-rich concentrate up to 40% of DM intake of cows showed additive effects on total DM and energy intakes improving milk yield, milk protein and casein contents without negative effects on milk fat concentration or yield. Pasture fiber digestion and nutritional parameters linked to healthy value of milk fat were not affectedEEA RafaelaFil: Salado, Eloy Eduardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Area de Investigación en Producción Animal; ArgentinaFil: Bretschneider, Gustavo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce. Agencia De Extensión Rural Necochea; ArgentinaFil: Cuatrin, Alejandra. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Area de Investigación en Producción Animal; ArgentinaFil: Descalzo, Adriana Maria. INTA-LABINTEX-Centre de Coopération Internationale en Recherche Agronomique pour le Déeveloppement (CIRAD), Déepartement PERSYST, UMR Qualisud; FranciaFil: Gagliostro, Gerardo Antonio. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Area de Investigación en Producción Animal; Argentin

Productive Response of Dairy Cows Fed with Different Levels of Totally Mixed Ration and Pasture

Forty multiparous Holstein cows in early lactation (66 ± 19 days) were assigned to one of four treatments that consisted in different ratios of total mixed rations (TMR) and pasture at 100% TMR (T0), 75:25 (T1) 50:50 (T2) and 25:75 (T3) over 9 weeks in autumn-winter. Measures of rumen parameters and digestion were performed on 4 additional Holstein cows in late lactation (287 days postpartum) fitted with permanent ruminal fistulae and producing 22.6 (±5.4) kg milk in a 4 × 4 Latin Square design. In T1 to T3 cows were taken to the grazing plot once they finished the pre-planned TMR intake and pasture was offered at 2 times the expected forage DM intake. Milk was analyzed for chemical composition, milk fatty acid (FA) profile and antioxidant compounds. The cows were individually weighed and body condition score (BCS) was determined. After the morning milking, blood samples were taken every 2 weeks and plasma was analyzed for glucose, urea, non-esterified fatty acids (NEFA), insulin, growth hormone (GH) and insulin-like growth factor (IGF-I). Herbage mass in pre grazing strips of pasture averaged 2540 ± 343 kg DM/ha. As TMR intake increased, production variables increased linearly excepting milk fat (3.88 g/100g) and milk protein (3.43 g/100g) contents that were not affected. Milk yield (kg/cow/d) resulted maximal in T0 (34.2) and linearly decreased (p < 0.01) with pasture intake averaging 32.1 (T1), 28.4 (T2) and 26.8 (T3) as a higher energy intake and a lower energy cost associated with grazing activity. Milk fat output (kg/cow/d) resulted higher in T0 (1.35) and T1 (1.25) compared to T2 (1.10) and T3 (1.04). Milk protein yield (kg/cow/d) was also higher in T0 (1.18) and T1 (1.11) compared to T2 (0.96) and T3 (0.92). Total DM (24.09 kg/cow/d) and energy (41.95 Mcal NEL/cow/d)) intakes resulted maximal in T0 decreasing as pasture replaced TMR without effects on conversion efficiency (1.48 kg milk/kg DM). Plasma concentration of glucose, insulin and IGF-I were not affected but GH and NEFA increased as pasture replaced TMR in T3. Ruminal pH (5.91) and total or VFA proportions did not differ but NH3-N concentration resulted higher in treatments with higher proportion of pasture. Kinetic parameters of DM and NDF digestion from pasture or corn silage were not affected. Milk FA profile and milk antioxidant quality showed unfavorably changes as TMR increased by a decrease in rumenic and linolenic acids and content of antioxidant vitamins, without effect on the atherogenicity index. Results suggested a depressing effect of the pasture on total DM and energy intake probably explained by qualitative deficiencies chemical composition of the forage and/or factors that affect animal behavior that may induce losses in body condition of high yielding dairy cows.EEA RafaelaFil: Salado, Eloy Eduardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Area de Investigación en Producción Animal; ArgentinaFil: Bretschneider, Gustavo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce. Agencia De Extensión Rural Necochea; ArgentinaFil: Cuatrin, Alejandra. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Area de Investigación en Producción Animal; ArgentinaFil: Descalzo, Adriana Maria. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Tecnología de Alimentos; ArgentinaFil: Gagliostro, Gerardo Antonio. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Area de Investigación en Producción Animal; Argentin

Improving the Quality of Milk Fatty Acid in Dairy Cows Supplemented with Soybean Oil and DHA-Micro Algae in a Confined Production System

The objective was to reduce saturated fatty acids (SFA) and increase conjugated linoleic acid (CLA, cis- 9, trans -11 C18:2), α-linolenic (cis- 9, cis- 12, cis- 15 C18:3) and docosahexaenoic (DHA, C22:6) contents in milk from confined dairy cows in order to promote a healthier option. The work was carried out in a commercial farm (Talar) located in Laguna del Sauce, Maldonado (Uruguay). Twenty four cows were assigned to one of two treatments (12 cows per treatment) over a 6 weeks experimental period. Treatments consisted in a control total mixed ration (C-TMR) without supplementary lipids (L) or the same TMR with the addition of 0.144 kg/cow∙day of algae and 0.72 kg/cow∙day of soybean oil (L-TMR). Chemical composition of the TMR (44.27% DM) averaged 15.94% for crude protein (CP), 38.20% neutral detergent fiber (NDF), 20.36% acid detergent fiber (ADF), 5.56% fat, 5.30% ash and 28.6% nonstructural carbohydrate (NSCH) with 1.81 Mcal/kg of net energy for lactation (NEL). After 39 days of feeding, individual milk samples were collected during three consecutive days. From the total milk collected, 20 ml were immediately used for chemical composition (Milko Scan) and 80 ml for analysis for milk FA profile. From week 3 onwards, milk production (kg/cow∙day) resulted higher (P < 0.001) in L-TMR (36.9) compared to C-TMR (35.2). At week 6 of trial, the difference in milk production averaged 5.14% for L-TMR. Supplementary lipids reduced (P < 0.002) milk fat concentration (g/100g) from 3.36 in C-TMR to 2.40 in L-TMR without effect (P = 0.43) on milk protein content (C-TMR = 3.20; L-TMR = 3.07 g/100g). Milk lactose (C-TMR = 4.86, L-TMR = 4.69 g/100g) and urea nitrogen contents (C-TMR = 21.18, L-TMR = 17.33 g/100g) tended (P < 0.056) to decrease in L-TMR as well as fat corrected milk output (C-TMR = 30.89, L-TMR = 29.49 kg/cow∙day, P < 0.098). Lipid supplementation reduced (−23%) milk content of C12:0 to C16:0 FA averaging 45.19 in C-TMR and 34.74 g/100g in L-TMR (P < 0.001). The atherogenic index (AI) of milk decreased (P < 0.001) from 2.69 in C-TMR to 1.50 in L-TMR (−44.2%). Concentration (g/100g) of elaidic (C18:1 trans -9) (0.23) and C18:1 trans -10 (0.44) FA increased (P < 0.001) in L-TMR milk. Milk vaccenic acid (trans- 11 C18:1, VA) increased from 1.08 in C-TMR to 2.56 g/100g of FA in L-TMR (P < 0.001). Milk CLA content (cis- 9, trans- 11 C18:2) increased (127%) from 0.62 in C-TMR to 1.41 g/100g FA in L-TMR milk. Content of α-linolenic acid resulted 20% higher (P < 0.001) in L-TMR milk (0.35 g/100g FA) compared to C-TMR (0.30 g/100g FA). Milk DHA increased from 0 in C-TMR to 0.14 g/100g FA in L-TMR. The omega-6/-3 ratio in C-TMR milk (9.61) was reduced (P < 0.001) to 6.78 in L-TMR milk. Milk oleic acid (cis -9 C18:1) resulted higher (P < 0.001) in L-TMR (23.65) than in C-TMR (19.75 g/100g FA). The nutritional value of milk fat from confined cows was naturally improved by feeding polyunsaturated FA in the ration, obtaining a reduction of saturated FA and increased levels of healthy FA (CLA, DHA and α-linolenic).Fil: Gagliostro, Gerardo Antonio. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Balcarce. Area de Producción Animal; Argentina.Fil: Antonacci, Liliana Elisabet. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Balcarce. Area de Producción Animal; Argentina.Fil: Perez, Carolina Daiana. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto Tecnología de Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Rossetti, Luciana. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto Tecnología de Alimentos; Argentina.Fil: Carabajal, Augusto. Establecimiento Agroindustrial Talar. Laguna del Sauce. Departamento de Maldonado; Urugua

Improving concentration of healthy fatty acids in milk, cheese and yogurt by adding a blend of soybean and fish oils to the ration of confined dairy cows

Compared to pasture based sistems, milk produced in confined dairy systems is characterized by a high saturated fat (SF) content with a lower concentration of healthy fatty acids (FA) such as vaccenic (VA, trans-11C18:1), conjugated linoleic cid (cis-9, trans-11 C18:2, CLA), α-linolenic (cis-9, cis-12, cis-15C18: 3), eicosapentaenoic (EPA, C20:5) and docosahexaenoic (DHA, C22:6) whose presence in milk and dairy products can be increased by feeding polyunsaturated FA (PUFA). The aim of the study was to determine the differences in milk composition and FA profile between a regular (Reg) milk (Reg-Milk), a Reg-Dambo type cheese (Reg-DCh) and a Reg yogurt (Reg-Yog) with that obtained after including a blend (7:1) of soybean (SO) and fish (FO) oils in the total mixed ration (TMR) of lactating dairy cows. The experiment was carried out at the Talar Farm located at Laguna del Sauce, Maldonado Department, Punta del Este, Uruguay Republic during a period of 30 experimental days using a single production batch of 29 Holstein cows. Within this batch, one group of 8 cows (1.88 ± 0.99 calves) in early lactation (135 ± 19 days postpartum) was selected to individually measure milk yield and composition. During the first 7 days of the experiment, cows were fed a TMR without oil-blend inclusion to obtain the Reg-Milk, Reg-DCh and Reg-Yog. From the 8th day onwards, the oil blend was added to the TMR at 4% DM (1.0 kg oil blend cow−1 day−1) and after 23 days of feeding, the modified (Mod-Milk) was analyzed and collected to elaborate the modified Dambo- type cheese (Mod-DCh) and Mod-yogurt (Mod-Yog). Milk yield was recorded daily in the selected 8 cows and milk composition was determined over two consecutive days prior to the start of blend-oil supply (Reg-Milk) and at the end of oil supplementation (Mod-Milk) on days 29th and 30th. Milk-tank samples of Reg-Mi and Mod-Mi were also collected and analyzed for chemical composition and milk FA profile. Cheese and yogurt were assayed for its FA profile. Differences in milk yield and composition and in the FA profile before and after oil-feeding were stated using the Student T-test for paired observations. Milk production (kg∙cow−1∙day−1) slightly (−6.7%) decreased (P < 0.03) from 36.89 (before) to 34.69 after oil feeding. Milk fat content decreased (P < 0.05) from 3.28 to 3.02 g 100 g−1 g leading to a lower (P < 0.02) yield (kg∙cow−1∙day−1) of fat corrected milk (4%FCM) from 32.83 (before) to 29.63 after oil. Milk protein content (g 100 g−1) increased (P < 0.04) from 2.89 (before) to 3.08 (after) oil feeding (+5.92%) a result confirmed (P < .01) in samples taken from the tank. Milk protein output (1.07 kg∙cow−1∙day−1) (P < 0.96), lactose (P < 0.65) and total solid (P < 0.38) contents were not affected. Concentration of non-fat solids (NFS) tended (P < 0.08) to increase from 8.50 in Reg-Mi, to 8.68 g 100 g−1 in Mod-Mi as it was observed (P < 0.001) in samples taken from the tank (8.78 vs. 9.93 g 100 g−1). Yield of NFS tended (P < 0.07) to decrease from 3.14 to 3.01 kg∙cow−1∙day−1 after oil supply. Content of atherogenic FA (C12:0 to C16:0) was significantly (P < 0.064) reduced (−10.29%) from 44.50 (Reg-Mi) to 39.92 g 100 g−1 (Mod-Mi) with a concomitant decrease (P < 0.10) in the atherogenic index (AI) from 2.45 (Reg-Mi) to 2.03 (Mod-Mi). Concentration (g 100 g−1 FA) of elaidic (trans-9 C18:1) and trans-10 C18:1 FA was low in Reg-Mi (0.22 and 0.34 respectively) but tended (P < 0.11) to increase in Mod-Mi (0.43 and 0.95). Concentration (g 100 g−1 FA) of VA resulted higher (+110%, P < 0.039) in Mod-Mi (2.42) compared to Reg-Mi (1.15). Total CLA content (g 100 g−1 FA) increased (P < 0.036) from 0.66 in Reg-Mi to 1.36 in Mod-Mi (+106%). Levels (g 100 g−1) of α-linolenic were higher (P < 0.004) in Reg-Mi (0.34) compared to Mod-Mi (0.29). The omega-6/omega-3 ratio was not changed (P < 0.13) averaging 5.98 in R-Mi and 7.18 in M-Mi. Oleic acid (cis-9 C18:1) content (g 100 g−1) remained unchanged (P < 0.504) averaging 21.99 in Reg-Mi and 22.86 in Mod-Mi. Composition of FA of the Mod-DCh was highly correlated (R2 = 0.999) with FA profile from its original Mod-Mi. A serving of the M-DCh (30 g) theoretically involved a 12.1% reduction in total fat consumption with 16.9% less in SF intake compared to the Reg-Ch. A serving of the M-DCh could putatively increase total CLA consumption by 72.7% compared to the Reg-DCh. Compared to Reg-Yo, a portion (178 g) of the Mod-Yo could increase (69.4%) total CLA intake. The nutritional value of milk fat was improved by feeding a blend of PUFA oils to confined dairy cows and the consumption of the mofified dairy products obtained could promote a lower intake of the potentially atherogenic saturated FA and some increase in healthy FA ingestion.Fil: Gagliostro, Gerardo Antonio. Instituto Nacional de Tecnología Agropecuaria (INTA), Estación Experimental Balcarce. Area de Producción Animal. Balcarce; Argentina.Fil: Antonacci, Liliana Elisabet. Instituto Nacional de Tecnología Agropecuaria (INTA), Estación Experimental Balcarce. Area de Producción Animal. Balcarce; Argentina.Fil: Perez, Carolina Daiana. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto Tecnología de Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina.Fil: Rossetti, Luciana. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto Tecnología de Alimentos; Argentina.Fil: Carabajal, Augusto. Establecimiento Agroindustrial Talar. Laguna del Sauce. Departamento de Maldonado; Urugua

Effect of Diet Supplementation with Combinations of Soybean and Linseed Oils on Milk Production and Fatty Acid Profile in Lactating Dairy Ewes

Thirty-six Pampinta ewes were used in a completely randomized design to examine the effectiveness of soybean (SO) and linseed (LO) oils to reduce the concentration of the atherogenic fatty acids (FA) of milk (C12:0 to C16:0) and increase the content of conjugated linoleic (cis-9, trans-11 C18:2) also called rumenic acid (RA) and vaccenic acids (trans-11C18:1, VA). Six ewes per treatment received a Control diet alone (71% alfalfa hay and 29% concentrate) or supplemented (0.24 kg/ewe·day) with pure oils (SO100 or LO100) or their blend at (%) SO75-LO25, SO50-LO50 and SO25-LO75. Milk yield, milk fat content and milk fat secretion were not affected. Milk protein content resulted higher in SO75-LO25, SO50-LO50 and SO25-LO75 without changes in milk protein yield. Total solid content of milk tended (p < 0.10) to increase after oil intake. Concentration of total atherogenic FA decreased and stearic, oleic and linolenic acids increased after oil intake. Milk content of VA and RA resulted higher in treatments with oils without differences between oil blends. The atherogenicity index (AI) in Control milk (2.23) was reduced (p < 0.001) by oil intake (1.15 to 1.37). The n-6/n-3 ratio averaged 7.27 in Control milk and was reduced (p < 0.001) by oils reaching a minimum value of 1.89 in LO100. Feeding polyunsaturated oils at 7% of total dry matter (DM) intake did not affect the productive response of dairy ewes resulting in an effective tool to improve the healthy value of milk fat. The SO50-LO50 blend showed the highest number of healthy changes in milk FA composition.Fil: Antonacci, Liliana Elisabet. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce. Area de Producción Animal; ArgentinaFil: Busetti, Margarita Rosa. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Anguil. Area de Producción Animal; ArgentinaFil: Rodríguez, María Alejandra. Instituto Nacional de Tecnología Industrial. Centro de Investigaciones Tecnológicas de la Industria Láctea; ArgentinaFil: Cano, Adriana Virginia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce. Area de Producción Animal; ArgentinaFil: Gagliostro, Gerardo Antonio. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Area de Producción Animal; Argentin

Obtención de leche bovina reducida en grasa saturada y naturalmente enriquecida en ácido linoleico conjugado = Production of bovine milk reduced in saturated fat and naturally enriched in conjugated linoleic acid

El objetivo del trabajo fue reducir la presencia de los ácidos grasos (AG) saturados potencialmente aterogénicos (C12:0, C14:0 y C16:0) de la leche y aumentar la presencia del ácido linoleico conjugado (CLA) en vacas lecheras estabuladas alimentadas con ración completamente mezclada (RCM) a través del aporte suplementario de ácidos grasos poliinsaturados (AGPI). Se utilizaron dos lotes de 70 vacas multíparas en el primer tercio de lactancia. Luego de seis semanas experimentales y durante cinco días consecutivos se obtuvieron cinco muestras de leche estándar (LE) provenientes del tanque colector del lote vacas sin AGPI suplementarios, y cinco muestras de leche CLA (LCLA) provenientes del tanque de las vacas suplementadas con los AGPI. El tenor graso (g/100g) de la LE (3,84) resultó superior (p<0,001) al de LCLA (2,84) por reducción (17,21%) de los AG potencialmente aterogénicos. El índice aterogénico fue mayor (p<0,001) en la LE (4,07) comparado al de la LCLA (2,58). La concentración del CLA aumentó (p<0,001) un 122% en LCLA (0,77 g/100 g) respecto al valor registrado en LE (0,34 g/100 g). El ácido oleico (g/100 g) resultó superior (p<0,001) en la LCLA (23,37) comparado con la LE (18,78). El aporte suplementario de AGPI permitió incrementar el valor saludable de la leche producida en un sistema de alimentación estabulado manteniendo una adecuada relación (6,59) omega-6/omega-3 en la leche y confrmando la plasticidad en la composición de los AG constitutivos de la grasa láctea

Milk fatty acid profile from grazing buffaloes fed a blend of soybean and linseed oils

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 L and H (P<0.19). Overall, these results indicate a pronounced improvement in the nutritional value of milk fat from grazing buffaloes fed little amounts (0.276g/day) of a blend of soybean and linseed oils.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) na gordura do leite aumentou (P<0,001) de 5,70 para 13,24g/100g AG em B e de 5,25 para 16,77 em A, resultando em maior teor de AV neste último (P<0,001). O teor basal de ácido rumênico aumentou expressivamente (P<0,001) em B (1,80 para 4,09g/100g AG, +127%) e A (1,60 para 4,61g/100g AG, +187%), não havendo diferenças entre tratamentos (P<0,19). No geral, estes resultados indicam uma melhora pronunciada no valor nutricional da gordura do leite de búfalas a pasto recebendo pequenas quantidades (0,276g/dia) de uma mistura de óleos de soja e linhaça na dieta.EEA BalcarceFil: Gagliostro, Gerardo Antonio. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Patiño, Exequiel Maria. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; ArgentinaFil: Sánchez Negrete, María Gabriela. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; ArgentinaFil: Sager, Gerardo Enrique. Universidad Nacional del Nordeste. Facultad de Ciencias Veterinarias; ArgentinaFil: Castelli, Laura. Instituto Nacional de Tecnología Industrial. Centro de Investigaciones Tecnológicas de la Industria Láctea; ArgentinaFil: Antonacci, Liliana. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; ArgentinaFil: Raco, Fernando. Instituto Nacional de Tecnología Industrial. Centro de Investigaciones Tecnológicas de la Industria Láctea; ArgentinaFil: Gallello, Lucas. Instituto Nacional de Tecnología Industrial. Centro de Investigaciones Tecnológicas de la Industria Láctea; ArgentinaFil: Rodriguez, M.A. Instituto Nacional de Tecnología Industrial. Centro de Investigaciones Tecnológicas de la Industria Láctea; ArgentinaFil: Cañameras, Carlos. Instituto Nacional de Tecnología Industrial. Centro de Investigaciones Tecnológicas de la Industria Láctea; ArgentinaFil: Zampatti, Mariela. Instituto Nacional de Tecnología Industrial. Centro de Investigaciones Tecnológicas de la Industria Láctea; ArgentinaFil: Bernal, Claudio Adrian. Universidad Nacional del Litoral. Facultad de Bioquímica y Ciencias Biológicas. Departamento de Ciencias Biológicas. Cátedra de Bromatología y Nutrición; Argentina

Effects of supplementation with increasing levels of energy concentrate on the productive response and ruminal digestion of dairy cows grazing lucerne pasture

The aim of the study was to determine the effect of three levels of energy concentrate intake on dry matter (DM) and energy intake, milk yield and composition, rumen environment and pasture neutral detergent fiber (NDF) digestion. Twelve Holstein multiparous cows in early lactation (69.0 ± 5 days postpartum) producing 32.8 (±4.0) kg milk were assigned to three treatments at (kg/cow day) 3.5 (T3.5), 7.0 (T7.0) and 10.5 (T10.5) kg concentrate in a 3 × 3 Latin Square design. Parameters of ruminal environment and neutral detergent fiber (NDF) digestion were obtained using 3 additional rumen cannulated cows. Concentrate was composed (as fed) by corn grain (68%), soybean meal (22%), wheat bran (8%) and a vitamin-mineral premix including monensin and thoroughly consumed. Yields (kg/cow day-1) of milk, 4% fat corrected milk (4% FCM 4%) and energy corrected milk (ECM) resulted higher (p < 0.05) in T7.0 (29.6, 26.1 and 25.7) compared to T3.5 (27.7, 24.5 and 24.2) but similar to those obtained in T10.5 (30.6, 26.2 and 26.0). Milk protein yield increased linearly (p < 0.01) from 0.82 to 0.92 kg/cow day-1 without effects on yield of milk fat. Concentrations (g/100 g) of milk fat (3.19), protein (2.97), total solids (11.75), non-fat solids (8.60) and casein (2.40) did not differ. Milk lactose content (g/100 g) was linearly increased (p < 0.02) from 4.91 to 4.98 whereas milk urea decreased (p < 0.01) from 0.048 to 0.043. Intakes of DM and energy increased with concentrate level without effects on conversion efficiency. Changes in live weight (LW), body condition score (BCS) and concentrations of plasma non-esterified fatty acids (NEFA), glucose, insulin, somatotrophin (GH) and insulin-like growth factor (IGF-I) were not affected. Plasma urea levels resulted lower (p < 0.05) in T10.5. Ruminal pH and ammonia nitrogen (N-NH3) resulted lower (p < 0.05) in T10.5 compared to T3.5. Concentration of total volatile fatty acids (VFA) was higher (p < 0.05) in T3.5 due to the increase in acetate and butyrate while the acetate: Propionate ratio remained unchanged. Pasture NDF digestion was affected as concentrate intake increased. To increase milk protein yield and reduce concentrations of N-NH3 in rumen and milk, feeding an energy concentrate at 41% of total DM intake resulted an effective tool.EEA RafaelaFil: Salado, Eloy Eduardo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Area de Investigación en Producción Animal; ArgentinaFil: Bretschneider, Gustavo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce. Agencia De Extensión Rural Necochea; ArgentinaFil: Cuatrin, Alejandra. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Rafaela. Area de Investigación en Producción Animal; ArgentinaFil: Gagliostro, Gerardo Antonio. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Balcarce; Area de Investigación en Producción Animal; Argentin