The effects of supplementation with sunflower and soybean oils on the fatty acid profile of milk fat from grazing dairy cows

Copyright © INRA, EDP Sciences, 2005.The objective of this study was to observe the effect of supplementation with vegetable oils (VO) on the fatty acid profiles and conjugated linoleic acid (CLA) content of milk fat. Twelve dairy cows in mid lactation fed on pasture were blocked by body weight, milk production and days in lactation and randomly allocated from blocks to 3 treatments repeated in a Latin square design with periods of 28 day duration. The treatments were as follows: cows on pasture supplemented with 5 kg concentrate per head per day (C), supplemented with 4.5 kg concentrate + 0.5 kg sunflower oil per head per day (SFO) and supplemented with 4.5 kg concentrate + 0.5 kg soybean oil per head per day (SBO). The animals were grazed as a group and were stocked at 2.5 heads per hectare. The treatments had no effect on milk yield or protein yield and content, but decreased milk fat yield and content (P < 0.05). Milk fat from the cows supplemented with VO had a lower concentration of short and medium chain fatty acids (P < 0.05) and a higher concentration of long chain fatty acids (P < 0.05). The addition of VO to the diet also resulted in a reduction in saturated and an increase in unsaturated fatty acids of milk fat (P < 0.05). The hypercholesterolemic fatty acids in milk fat (i.e. C12:0, C14:0 and C16:0) decreased while the concentration of oleic and linoleic acids increased with VO (P < 0.05). There was no effect on linolenic acid. Finally, the inclusion of VO in the diet increased (P < 0.05) the contents in milk fat of the various cis/trans isomers of oleic acid (including trans-vacenic, TVA) and of CLA which increased by 61%

Effect of diet on the fatty acid pattern of milk from dairy cows

Copyright © INRA, EDP Sciences, 2004.Twelve dairy cows 130 days in milk were sorted by milk production and body weight and assigned to three feeding regimens in a 3 × 3 Latin-square design, in order to study the effects of diet on milk fatty acid (FA) composition. The cows were fed a total mixed ration (TMR) consisting of corn silage (60%) and concentrate (40%) on dry matter basis, or grazed pasture, without (P) or with 5 kg•d-1 concentrate as a supplement (SP). Supplemented grazing dairy cows produced significantly more milk than the cows on the TMR and P diets (P < 0.05). The supplementation of grazing dairy cows with a low fat concentrate did not significantly affect the milk fat FA profile. The pasture diet, with a supplement or not, decreased the concentration of saturated FA (P < 0.05) and increased the concentration of unsaturated FA (P < 0.05), of milk fat as compared to the TMR diet. The reduction in medium-chain FA was offset in large part by increases in long-chain FA (mainly oleic acid). The concentrations of conjugated linoleic acid (CLA) (P < 0.05) and trans-vaccenic acid were higher (P < 0.05) in the milk fat from the grazing cows. The results showed substantial variation among individual cows within treatments on milk fat content of CLA. Significant correlations were found for individual cow's milk fat CLA content across diets. Overall, this study indicates that the concentration of CLA in milk fat is enhanced by the dietary intake of pasture and that moderate low fat concentrate supplementation of grazing dairy cows increases performance without compromising the FA profile of milk fat

Effects of grass silage and soybean meal supplementation on milk production and milk fatty acid profiles of grazing dairy cows

Copyright © American Dairy Science Association, 2008.The effects of supplementation with grass silage and replacement of some corn in the concentrate with soybean meal (SBM) on milk production, and milk fatty acid (FA) profiles were evaluated in a replicated 4 × 4 Latin square study using 16 dairy cows grazing pasture composed of ryegrass, Kentucky bluegrass, and white clover. Each experimental period lasted for 3 wk. The 4 dietary treatments were PC, 20 h of access to grazing pasture, supplemented with 6 kg/d of corn-based concentrate mixture (96% corn; C); PCSB, 20 h of access to grazing pasture, supplemented with 6 kg/d of corn- and SBM-based concentrate mixture (78% corn and 18% SBM; CSB); SC, 7 h of access to grazing pasture during the day and 13 h of ad libitum access to grass silage at night, supplemented with 6 kg/d of C concentrate; and SCSB, 7 h of access to grazing pasture during the day and 13 h of ad libitum access to grass silage at night, supplemented with 6 kg/d of CSB concentrate. The concentrate mixtures were offered twice each day in the milking parlor and were consumed completely. Grass silage supplementation reduced dietary crude protein and concentration of total sugars, and dietary SBM inclusion increased dietary crude protein concentration and decreased dietary starch concentration. Milk yield and energy-corrected milk were increased by SBM supplementation of cows with access to grass silage. Milk protein concentration was lower in cows offered grass silage, regardless of whether SBM was fed. Dietary SBM inclusion tended to increase milk fat concentration. Plasma urea N was reduced by silage feeding and increased by SBM supplementation. Supplementation with grass silage overnight could represent a useful strategy for periods of lower pasture availability. Dietary inclusion of SBM in solely grazing cows had no effects on milk production and composition, exacerbated the inefficient capture of dietary N, and increased diet cost. Grass silage supplementation affected milk FA profiles, increasing both the FA derived from de novo synthesis and those derived from rumen microbial biomass, and decreasing the sum of C18 FA (mostly derived from diet or from mobilization of adipose tissue reserves). Milk fat concentrations of conjugated linoleic acid cis-9, trans-11, vaccenic acid (18:1 trans-11), and linolenic acid (18:3n-3) were unaffected by grass silage supplementation, suggesting that partial replacement of pasture by unwilted grass silage does not compromise the dietary quality of milk fat for humans

Productive and reproductive performance of Romney Marsh and Merino Branco sheep in the Azores under different feeding regimens

Copyright © 2005 Elsevier B.V. All rights reserved.The objective of this study was to compare the productive and reproductive performances of Romney Marsh (RM) and Merino Branco (MB) ewes in the Azores. In a preliminary trial, fertility, prolificacy and fecundity of 25 RM and 27 MB ewes, mortality rate of lambs born and growth rate of lambs (14 RM and 20 MB) from birth to weaning at 24 kg live weight were determined. In a second trial following weaning, the same group of lambs were raised on pasture and supplemented either with concentrate or maize silage until slaughter (101 days later), and growth rate, carcass and meat characteristics were evaluated. Reproductive indices (fertility: 96% versus 93%; prolificacy: 117% versus 140%; fecundity: 112% versus 130%) and mortality rates (18% versus 17%) for RM and MB, respectively, were not significantly different. Pre-weaning gain was higher (P < 0.05) in RM lambs than BM lambs (236 ± 8.6 g/day versus 214 ± 5.8 g/day). After weaning, RM lambs grew 20% faster than MB when supplemented with concentrate, but 16% slower when supplemented with maize silage (P < 0.05). Growth of males was higher than that of females (110.3 ± 10.8 g/day versus 73.3 ± 9.3 g/day, P < 0.001). Lambs supplemented with concentrate grew twice as much as animals supplemented with maize silage (129.9 ± 9.8 g/day versus 60.5 ± 3.8 g/day, P < 0.01). Dressing percentage was not affected by breed, diet or sex. Characteristics of carcass and meat did not differ between breeds. Supplementation with concentrate resulted in thicker, fatter and wider carcasses (P < 0.01) compared to supplementation with maize silage. It was concluded that the RM and MB sheep breeds are not very different in terms of growth potential and carcass characteristics. RM performed better with improved feeding conditions, while MB was less affected when food quality declined. MB appears to be a good alternative breed for exploitation in the Azores

Investigação na área de nutrição e alimentação animal

Jornadas "Ciência nos Açores - que futuro?", Biblioteca Pública e Arquivo Regional de Ponta Delgada, 7 e 8 de Junho de 2013.A equipa de investigadores que trabalha na Área de Nutrição e Alimentação Animal desenvolve os seus trabalhos de investigação segundo três linhas principais: 1. Estratégias alimentares que melhoram as características sensoriais e a qualidade da gordura (conjugados do ácido linoleico, CLA, ómegas 3) do leite e carne de bovinos; 2. Estratégias para a melhoria da eficiência nutritiva; 3. Estudo das Forragens Açorianas.ABSTRACT: The research team involved in animal feeding and nutrition develops its studies according to 3 main research lines: 1. Feeding strategies intended to improve sensorial characteristics and fat quality (e.g. CLA – conjugated linoleic acid – and ómega-3 fatty acids) in milk and beef; 2. Strategies to improve nutritive efficiency in animal production; 3. Evaluation of the Azorean forrages

Influence of dietary fish oil on conjugated linoleic acid, omega-3 and other fatty acids in milk fat from grazing dairy cows

Copyright © 2004 Elsevier B.V. All rights reserved.The main objective of this study was to evaluate the effect of supplementation with fish oil on fatty acid (FA) composition of milk fat from grazing dairy cows with particular emphasis on omega-3 and conjugated linoleic acid. Twelve dairy cows in mid-lactation were blocked by live weight, days in lactation and milk production and randomly assigned to the experimental groups corresponding to 3 different feeding regimens which were applied 3 times with 28-day duration according to a Latin square design. Cows were stocked at 2.5 heads per hectare and supplemented with 4 kg concentrate/cow/day (C), concentrate mixed with 160 g sardine oil (LFO) and concentrate mixed with 320 g sardine oil (HFO). Supplementation with fish oil (FO) resulted in a significant (P<0.05) decrease in milk production and milk fat content and production. Supplementation with 320 g FO decreased (P<0.05) milk protein content and production. The ratio protein/fat in milk increased with the level of FO supplemented (P<0.05). Significant correlations were detected between some FA in milk fat and milk fat content. FO supplementation had no effect on concentration of medium chain FA but originated a decrease (P<0.05) in concentration of short and long chain FA in milk fat. The sum of saturated FA decreased (P<0.05) with the inclusion of FO in diet while the sum of unsaturated FA remains unchanged. Proportions of stearic and oleic FA in milk fat decreased and trans-vaccenic FA increase with FO supplementation (P<0.05). Milk fat concentration of polyunsaturated n-3 FA was higher in treatment HFO. Concentration of very long chain omega FA in milk fat (i.e. C20:5-EPA e C22:6-DHA) increased by 2.7-fold with 160 g FO and by 5- to 7-fold with 320 g FO. However, the level of transfer efficiency of these FA from FO to milk fat was only 3.3% in treatment LFO and 4.0% in treatment HFO. CLA concentrations in milk fat were particularly high in this experiment and increased with the level of FO supplementation (P<0.05)

Effect of diet on the fatty acid pattern of milk from dairy cows

Copyright © INRA, EDP Sciences, 2004.Twelve dairy cows 130 days in milk were sorted by milk production and body weight and assigned to three feeding regimens in a 3 × 3 Latin-square design, in order to study the effects of diet on milk fatty acid (FA) composition. The cows were fed a total mixed ration (TMR) consisting of corn silage (60%) and concentrate (40%) on dry matter basis, or grazed pasture, without (P) or with 5 kg•d-1 concentrate as a supplement (SP). Supplemented grazing dairy cows produced significantly more milk than the cows on the TMR and P diets (P < 0.05). The supplementation of grazing dairy cows with a low fat concentrate did not significantly affect the milk fat FA profile. The pasture diet, with a supplement or not, decreased the concentration of saturated FA (P < 0.05) and increased the concentration of unsaturated FA (P < 0.05), of milk fat as compared to the TMR diet. The reduction in medium-chain FA was offset in large part by increases in long-chain FA (mainly oleic acid). The concentrations of conjugated linoleic acid (CLA) (P < 0.05) and trans-vaccenic acid were higher (P < 0.05) in the milk fat from the grazing cows. The results showed substantial variation among individual cows within treatments on milk fat content of CLA. Significant correlations were found for individual cow's milk fat CLA content across diets. Overall, this study indicates that the concentration of CLA in milk fat is enhanced by the dietary intake of pasture and that moderate low fat concentrate supplementation of grazing dairy cows increases performance without compromising the FA profile of milk fat

Effects of grass silage and soybean meal supplementation on milk production and milk fatty acid profiles of grazing dairy cows

Copyright © American Dairy Science Association, 2008.The effects of supplementation with grass silage and replacement of some corn in the concentrate with soybean meal (SBM) on milk production, and milk fatty acid (FA) profiles were evaluated in a replicated 4 × 4 Latin square study using 16 dairy cows grazing pasture composed of ryegrass, Kentucky bluegrass, and white clover. Each experimental period lasted for 3 wk. The 4 dietary treatments were PC, 20 h of access to grazing pasture, supplemented with 6 kg/d of corn-based concentrate mixture (96% corn; C); PCSB, 20 h of access to grazing pasture, supplemented with 6 kg/d of corn- and SBM-based concentrate mixture (78% corn and 18% SBM; CSB); SC, 7 h of access to grazing pasture during the day and 13 h of ad libitum access to grass silage at night, supplemented with 6 kg/d of C concentrate; and SCSB, 7 h of access to grazing pasture during the day and 13 h of ad libitum access to grass silage at night, supplemented with 6 kg/d of CSB concentrate. The concentrate mixtures were offered twice each day in the milking parlor and were consumed completely. Grass silage supplementation reduced dietary crude protein and concentration of total sugars, and dietary SBM inclusion increased dietary crude protein concentration and decreased dietary starch concentration. Milk yield and energy-corrected milk were increased by SBM supplementation of cows with access to grass silage. Milk protein concentration was lower in cows offered grass silage, regardless of whether SBM was fed. Dietary SBM inclusion tended to increase milk fat concentration. Plasma urea N was reduced by silage feeding and increased by SBM supplementation. Supplementation with grass silage overnight could represent a useful strategy for periods of lower pasture availability. Dietary inclusion of SBM in solely grazing cows had no effects on milk production and composition, exacerbated the inefficient capture of dietary N, and increased diet cost. Grass silage supplementation affected milk FA profiles, increasing both the FA derived from de novo synthesis and those derived from rumen microbial biomass, and decreasing the sum of C18 FA (mostly derived from diet or from mobilization of adipose tissue reserves). Milk fat concentrations of conjugated linoleic acid cis-9, trans-11, vaccenic acid (18:1 trans-11), and linolenic acid (18:3n-3) were unaffected by grass silage supplementation, suggesting that partial replacement of pasture by unwilted grass silage does not compromise the dietary quality of milk fat for humans

O conhecimento do passado para apoiar, no futuro, a Agricultura, Zootecnia e Tecnologia de Alimentos

Jornadas "Ciência nos Açores - que futuro?", Biblioteca Pública e Arquivo Regional de Ponta Delgada, 7 e 8 de Junho de 2013