Fatty Acid Composition Of Milk Fat Research Articles

The effect of 2-day heat stress on the lipid composition of bovine milk and serum

Milk and serum were collected from dairy cows before and during a 2-day heat challenge. The concentrations of free short-chain fatty acids (SCFAs), the fatty acid (FA) profile, and the abundance of the major species of phosphatidylcholine (PC), phosphatidylethanolamine (PE), and sphingomyelin (SM) were measured, and samples collected during heat exposure were compared with those collected prior to heat exposure. It was found that a 2-day heat challenge did not alter the global FA composition of milk fat nor the content of the major phospholipids. Although the concentration of SCFAs C3 and C4 and some lysophosphatidylcholine (LPC) species in milk was found to be associated with the forage type, neither of these lipid molecules can be used as an indicator of acute heat stress. While it is a positive finding that short-term heat stress has no detrimental effect on the FA composition or the nutritive quality of milk fat, this study highlights the complexity of validating a milk lipid biomarker for heat stress in dairy cows.

Analysis of qualitative and quantitative indicators of milk production and processing at the enterprises of the Akmola region

The primary tasks are the development of the agro-industrial complex of the Republic of Kazakhstan and the provision of high-quality products to the population. The Akmola region is one of the country's most developed agricultural and industrial regions. The assessment of qualitative and quantitative indicators of milk production and processing in the Akmola region reflects the development dynamics of the dairy industry of the country and the main problems that need to be solved; therefore, research on this issue is relevant. The purpose of the study was to analyse the quantitative and qualitative indicators of milk production and processing at the enterprises of the Akmola region, review research on the development of formulations based on the raw materials of the area, and study factors affecting the quality of dairy products. The main method used in the study was the analysis of the suitability of milk of the Akmola region as a raw material for producing cheese fermented milk. It was found that, in general, the quality of milk of the Akmola region in terms of fat, protein, minerals, and lactose, the fatty-acid composition of milk fat, the content of somatic cells is good. The specificity of the region, which consists in the fact that most of the raw materials for milk processing plants are supplied by private farms, leads to the variability of microbiological indicators of milk and the content of somatic cells, which limits the use of milk in the production of certain types of cheese. It was concluded that there is a necessity in the development of new recipes, considering the characteristics of raw and powdered milk produced in the Akmola region, which will increase the range of high-quality dairy products, which will be distributed within the country and for export.

Seasonal variation in fatty acid and triacylglycerol composition of bovine milk fat

The aim of this study was to assess the effects of seasonal variation on the changes of the fatty acid (FA) and triacylglycerol (TAG) composition of bovine milk fat (MF) in a nonseasonal milking system. Weekly milk samples were collected from 14 dairy factories and pooled per week as representative samples of the average Dutch bovine milk. The sample collection started in May 2017 and finished in April 2018, resulting in a total of 52 samples, corresponding to each week of the year. The samples were analyzed for MF content (%) and FA and TAG composition using gas chromatography with flame-ionization detection. The increased intake of C18:3 cis-9,12,15 through grass feeding in spring and summer was associated with major changes in MF FA composition, including reduced proportions of de novo synthesized FA and presence of several rumen biohydrogenation products and conjugated linoleic acid isomers in MF. These changes in seasonal FA composition had an effect on TAG seasonal variation. The TAG seasonal variation showed that all TAG groups were significantly different between months. The low molecular weight and the medium molecular weight TAG groups increased in winter and decreased in summer, whereas the high molecular weight TAG groups increased in summer and decreased in winter. Based on pooled monthly samples, MALDI-TOF-mass spectrometry allowed the analysis of even- and odd-chain TAG species in MF based on their total carbon number and number of double bonds. These analyses indicated saturated TAG species to be greatest in winter, whereas monounsaturated, polyunsaturated, and odd-chain TAG species were greatest in summer. Our study showed that TAG seasonal variation in a nonseasonal milking system is influenced by the variation in FA composition throughout the seasons.

Genetic parameters of measures and population-wide infrared predictions of 92 traits describing the fine composition and technological properties of milk in Italian Simmental cattle

The objectives of this study were to estimate, for the Italian Simmental cattle population, genetic parameters for 92 traits and their infrared predictions (IP) and to investigate the genetic relationship between measured traits (MT) and IP. Data for milk fat fatty acid composition (n = 1,040), detailed protein composition (n = 3,337), lactoferrin (n = 558), pH (n = 3,438), coagulation properties (n = 3,266), curd yield and composition obtained by a micro-cheese making procedure (n = 1,177), and content of Ca, P, Mg, and K (n = 689) were obtained using reference laboratory analysis. Infrared prediction for all the investigated traits was performed using 143,198 spectra records belonging to 17,619 Italian Simmental cows. (Co)variance components for MT and their IP were estimated in a set of bivariate animal model REML analyses and genetic correlations between MT and IP were estimated using all IP obtained at the population level. A significant positive relationship was observed between the coefficient of determination of the infrared prediction models and the phenotypic and genetic variation of the IP. The decrease in the estimated genetic variance of IP compared with MT was on average 64%. For traits exhibiting calibration models with coefficients of determination in cross-validation (R2CV) greater than 0.9, the decrease in the genetic variance ranged from approximately 20 to 50%. Most traits (88 out of 92) exhibited lower heritability estimates for IP than for the corresponding MT. The estimated genetic correlations between IP and MT (ra) were in general very high. A positive relationship (r = 0.57) between R2CV of calibration models and the estimated ra has been detected. For calibration models exhibiting R2CV higher than 0.75, ra were greater than 0.9. The variability in the estimated correlations increased when R2CV decreased, and for calibration models of moderate predictive ability, estimates of ra ranged from 0.2 to 1. Genetic parameter estimates suggested that IP can be used as indicator traits in breeding programs for the enhancement of fine composition and technological properties of milk. The genetic gain achievable selecting for IP is expected to be high for fatty acid composition, minerals, and for technological properties of milk, whereas it will be low for casein and whey protein composition and for the content of lactoferrin.

Manipulation of milk fatty acid composition in lactating cows: Opportunities and challenges

Public health policies recommend a population wide decrease in the consumption of saturated fatty acids (SFA) to lower the incidence of cardiovascular and metabolic diseases. In most developed countries, milk and dairy products are the major source of SFA in the human diet. Altering milk fat composition offers the opportunity to lower the consumption of SFA without requiring a change in eating habits. Supplementing the diet of lactating cows with oilseeds, plant oils and marine lipids can be used to replace the SFA in milk fat with monounsaturated fatty acids (MUFA), and to a lesser extent, polyunsaturated fatty acids (PUFA). Due to ruminal metabolism, the decreases in milk SFA are also accompanied by increases in trans fatty acids (TFA), including conjugated isomers. The potential to lower SFA, enrich cis MUFA and PUFA, and alter the abundance and distribution of individual TFA in milk differs according to oil source, form of lipid supplement and degree of oilseed processing, and the influence of other components in the diet. The present review summarises recent evidence on changes in milk fat composition that can be achieved using dietary lipid supplements and highlights the challenges to commercial production of modified milk and dairy products. A meta‐analysis on the effects of oilseeds on milk fatty acid composition is also presented.Practical applications: Milk and dairy products are the major source of SFA in the diet in most developed countries. Including oilseeds, plant oils, and to a lesser extent, marine lipids in the diet of lactating cows can replace SFA with MUFA and PUFA in milk offering a mechanism to lower SFA consumption in human populations. Understanding the sources of variation in milk fat composition responses, and adjusting other ingredients in the diet to accommodate lipid supplements offers the opportunity to consistently produce milk with an altered fatty acid composition. However, commercialisation of dedicated supply chains will depend on whether the added costs of production and segregation of modified milk for processing can be recovered at retail.Dairy products are the major source of saturated fatty acids in diets of developed countries. There are various dietary strategies that can be employed at the dairy cow level to alter milk fat fatty acid composition, but it is important to understand variations in cow response to these interventions to consistently produce milk with altered fatty acid composition.

Effect of corn silage harvest maturity and concentrate type on milk fatty acid composition of dairy cows

The variation in maturity at harvest during grain filling has a major effect on the carbohydrate composition (starch:NDF ratio) and fatty acid (FA) content of corn silages, and can alter the FA composition of milk fat in dairy cows. This study evaluated the effect of silage corn (cv. Atrium) harvested and ensiled at targeted DM contents of 300, 340, 380, and 420g/kg of fresh weight and fed to dairy cows in combination with a highly degradable carbohydrate (HC) or low-degradable carbohydrate concentrate, on the nutrient intake, milk yield, and composition of milk and milk fat. Sixty-four multiparous Holstein-Friesian dairy cows in their first week of lactation were assigned to the 8 dietary treatments according to a randomized complete block design. The 8 dietary treatments consisted of a factorial combination of the 4 corn silages and the 2 concentrates. Corn silages were offered ad libitum as part of a basal forage mixture, whereas the concentrates were given at the rate of 8.5kg of DM/cow per day during the 15-wk experimental period. Dry matter, crude protein, and energy intakes did not differ across the corn silages. However, the intake of starch increased, and those of NDF and C18:3n-3 decreased with increasing maturation. Milk yield and composition were not different across the corn silages. Yield (kg/d) of milk, protein, and lactose was higher for low-degradable carbohydrate compared with HC concentrate-fed groups. Increasing maturity of corn silages decreased the content of C18:3n-3 and total n-3 and increased the n-6:n-3 ratio in milk fat. Concentrate type significantly altered the composition of all trans FA, except C18:2 trans-9,12. Inclusion of the HC concentrate in the diets increased the contents of all C18:1 trans isomers, C18:2 cis-9,trans-11, and C18:2 trans-10,cis-12 conjugated linoleic acid in milk fat. Milk fat composition was strongly influenced by the stage of lactation (wk 3 to 10). The content of all even short- and medium-chain FA changed with lactation, except C8:0 and C10:0. The content of C12:0, C14:0, and C16:0 and total saturated FA increased and the content of C18:0, C18:1 cis total, and total cis monounsaturated FA decreased with lactation. Maturity of the corn silages at harvest did not affect the production performance of dairy cows, but resulted in a decreased content of C18:3n-3, total n-3, and an increased n-6:n-3 ratio in the milk fat of dairy cows.

Comparison of Conjugated Linoleic Acid and Other Fatty Acid Content of Milk Fat of Mafriwal and Jersey Cows

Special attention has been given to the milk Fatty Acids (FA) that have a beneficial effect for human health such as mono and poly unsaturated fatty acids in particularly the Conjugated Linoleic Acids (CLA). This study was undertaken to investigate the milk fat contents of CLA variables (CLA and CLA-desaturase index) and other FA composition of Mafriwal and Jersey cows under same feeding system. In addition, the relationship between these two CLA variables with milk production and milk fat percent was determined. All the cows were grazed on pasture and given 5.5 kg of concentrate per head daily. Milk FA composition was determined using gas chromatography after extraction of milk fat using modified Folch's method. The results showed a significant variation (p<0.05) in the FA contents of the two breeds. The cis-9, trans-II CLA and CLA-desaturase index in milk fat of Mafriwal were significantly higher (p<0.05) than that of Jersey cows. Mafriwal cows produced significantly (p<0.05) higher concentrations of C18:0, C18:1cis-9, C18:3 and C20:1 than that of Jersey, while Jersey cows produced significantly (p<0.05) higher concentrations of C12:0 and C14:0 than Mafriwal cows. Additionally, significant positive correlations were observed between CLA variables and milk production. This study indicates that the breed of cows has an effect on CLA and other FA composition of milk fat and Mafriwal cows produced significantly higher percentages of CLA than Jersey cows which would provide better benefits for human health. Furthermore, the milk fat content of CLA and CLA-desaturase index were positively related to the milk production.

Genetic determination of fatty acid composition in Spanish Churra sheep milk

The objective of this study was to estimate the genetic variation of ovine milk fatty acid (FA) composition. We collected 4,100 milk samples in 14 herds from 976 Churra ewes sired mostly by 15 AI rams and analyzed them by gas–liquid chromatography for milk fatty acid composition. The studied traits were 12 individual FA contents (proportion in relation to the total amount of FA), 3 groups of fatty acids [saturated fatty acids (SFA), monounsaturated FA (MUFA), and polyunsaturated FA (PUFA)], and 2 FA ratios (n-6:n-3 and C18:2 cis-9,trans-11:C18:1 trans-11). In addition, percentages of fat and protein and daily milk yield were studied. For the analysis, repeatability animal models were implemented using Bayesian methods. In an initial step, univariate methods were conducted to test the hypothesis of the traits showing additive genetic determination. Deviance information criterion and Bayes factor were employed as model choice criteria. All the studied SFA showed additive genetic variance, but the estimated heritabilities were low. Among unsaturated FA (UFA), only C18:1 trans-11 and C18:2 cis-9,cis-12 showed additive genetic variation, their estimated heritabilities being [marginal posterior mean (marginal posterior SD)] 0.02(0.01) and 0.11(0.04), respectively. For the FA groups, only PUFA showed significant additive genetic variation. None of the studied ratios of FA showed additive genetic variation. In second multitrait analyses, genetic correlations between individual FA and production traits, and between groups of FA and ratios of FA and production traits, were investigated. Positive genetic correlations were estimated among medium-chain SFA, ranging from 0 to 0.85, but this parameter was close to zero between long-chain SFA (C16:0 and C18:0). Between long- and medium-chain SFA, estimated genetic correlations were negative, around −0.6. Among those UFA showing significant additive genetic variance, genetic correlations were close to zero. The estimated genetic correlations among all the investigated FA, milk yield, and fat and protein percentages were not different from zero. Our results suggest that low additive genetic variation is involved in the determination of the FA composition of milk fat in Churra sheep under current production conditions, which results in low values of heritabilities.

Terpenes and fatty acid profiles of milk fat and “Bitto” cheese as affected by transhumance of cows on different mountain pastures

The evolution of fatty acid (FA) and terpenoid profiles was studied in milk (n=20) and “Bitto” (n=3), a protected designation of origin cheese produced in a restricted Italian alpine area. Milk came from 25 Italian Brown cows successively grazing pastures at 1400, 2100 and 2200m during transhumance in June–September 2006. The fat matter was analyzed for FAs and terpenes by means of gas chromatography and purge & trap/gas chromatography–mass spectrometry, respectively. FA composition of milk fat varied significantly (p<0.0001) in relation to contents of conjugated linoleic acid (CLA), stearic, linoleic and trans-vaccenic acids. Similar monoterpene profiles characterized milk fat from cows grazing the different pastures and the highest amount of terpenes was measured in milk coming from cows grazing at 1400m. High levels of δ3-carene in milk fat were likely related to the important presence of Ligusticum mutellina in the pasture. Only negligible amounts of sesquiterpenes were detected in milk fat whereas they were the most abundant class in fodder. Both FA and terpene profiles of ripened (70 days) cheeses resembled those of the original milks. Overall, results confirm the influence of the botanical composition of mountain pastures both in enhancing the ruminal synthesis of CLA and in modifying the FA and terpenoid profiles of milk and “Bitto” cheese. Nevertheless, neither the FA nor the terpenoid profiles revealed here can be considered as “unique” to “Bitto” cheese and, for this reason, they can hardly be assumed to be biomarkers for defining a specific relationship among grazing area, milk and “Bitto” cheese. They better represent the chemical fingerprint of the cow feeding, adopted in mountain areas.

Estimation of Heritability and Genetic Correlations for the Major Fatty Acids in Bovine Milk

The current cattle selection program for dairy cattle in the Walloon region of Belgium does not consider the relative content of the different fatty acids (FA) in milk. However, interest by the local dairy industry in differentiated milk products is increasing. Therefore, farmers may be interested in selecting their animals based on the fat composition. The aim of this study was to evaluate the feasibility of genetic selection to improve the nutritional quality of bovine milk fat. The heritabilities and correlations among milk yield, fat, protein, and major FA contents in milk were estimated. Heritabilities for FA in milk and fat ranged from 5 to 38%. The genetic correlations estimated among FA reflected the common origin of several groups of FA. Given these results, an index including FA contents with the similar metabolic process of production in the mammary gland could be used, for example, to increase the monounsaturated and conjugated fatty acids in milk. Moreover, the genetic correlations between the percentage of fat and the content of C14:0, C12:0, C16:0, and C18:0 in fat were −0.06, 0.55, 0.60, and 0.84, respectively. This result demonstrates that an increase in fat content is not directly correlated with undesirable changes in FA profile in milk for human health. Based on the obtained genetic parameters, a future selection program to improve the FA composition of milk fat could be initiated.

Effect of calcium salts of fish and palm oils on lactational performance of Holstein cows

Two experiments were conducted to determine the effect of source of fatty acids (FA) fed as tallow or calcium salts of fish and palm oils (CaSFO) on performance of dairy cows. In experiment 1, 738 multiparous Holstein cows were fed a diet with either 18 g/kg of tallow or 19 g/kg of CaSFO to supply equal amounts of FA in two replicates per treatment. In experiment 2, 331 multiparous cows were fed one of the two supplements described previously. In both experiments, all cows received a pre-treatment diet during the first 25 days in milk (DIM) consisting of half of each fat supplement (9 g/kg of tallow + 9.5 g/kg of CaSFO). Thereafter, cows received their respective diets for the first 145 DIM. Yields of milk and milk fat were not affected by dietary source of FA in both experiments. However, feeding CaSFO reduced concentration of true protein and solids-not-fat, as well as yields of true protein. Group and individual dry matter (DM) intakes and feed efficiency were not altered by treatment, but cows fed CaSFO had higher total tract apparent digestibility of DM. Cows fed CaSFO had increased concentrations of eicosapentaenoic, docosahexaenoic, conjugated linoleic acid ( cis 9, trans 11), C18:1 trans 9, and C18:1 trans 11 FA in milk fat. Treatment had no effect on blood parameters and estimated energy balance, but cows fed CaSFO lost more body condition. Feeding CaSFO at 19 g/kg of the diet modified the FA composition of milk fat compared with tallow, but did not improve lactational performance of dairy cows. The present findings suggest that supplementation with tallow or CaSFO results in similar lactational performance, with changes in FA profile of milk fat.

Major Advances in Concentrated and Dry Milk Products, Cheese, and Milk Fat-Based Spreads

Advances in dairy foods and dairy foods processing since 1981 have influenced consumers and processors of dairy products. Consumer benefits include dairy products with enhanced nutrition and product functionality for specific applications. Processors convert raw milk to finished product with improved efficiencies and have developed processing technologies to improve traditional products and to introduce new products for expanding the dairy foods market. Membrane processing evolved from a laboratory technique to a major industrial process for milk and whey processing. Ultra-filtration and reverse osmosis have been used extensively in fractionation of milk and whey components. Advances in cheese manufacturing methods have included mechanization of the making process. Membrane processing has allowed uniform composition of the cheese milk and starter cultures have become more predictable. Cheese vats have become larger and enclosed as well as computer controlled. Researchers have learned to control many of the functional properties of cheese by understanding the role of fat and calcium distribution, as bound or unbound, in the cheese matrix. Processed cheese (cheese, foods, spreads, and products) maintain their importance in the industry as many product types can be produced to meet market needs and provide stable products for an extended shelf life. Cheese delivers concentrated nutrients of milk and bio-active peptides to consumers. The technologies for the production of concentrated and dried milk and whey products have not changed greatly in the last 25 yr. The size and efficiencies of the equipment have increased. Use of reverse osmosis in place of vacuum condensing has been proposed. Modifying the fatty acid composition of milkfat to alter the nutritional and functional properties of dairy spread has been a focus of research in the last 2 decades. Conjugated linoleic acid, which can be increased in milkfat by alteration of the cow's diet, has been reported to have anticancer, anti-atherogenic, antidiabetic, and antiobesity effects for human health. Separating milk fat into fractions has been accomplished to provide specific fractions to improve butter spreadability, modulate chocolate meltability, and provide texture for low-fat cheeses.

Determining Fat, Protein, and Lactose in Milk from Cows Fed Formaldehyde Protected Sunflower-Soybean Supplement

To determine whether feeding cows protected lipid supplement influences reliability of analyses of milk composition, we measured fat, protein, and lactose in milk produced by two groups of six Holstein cows, one fed a conventional hay-concentrate ration and one a ration containing protected sunflower-soybean supplement. Analyses were of 36 samples from each group collected biweekly over 12 wk. The three constituents were measured by an Infrared Milk Analyzer. Reference methods were Babcock test for fat, Udy dye-binding for protein, and a polarimetric method for lactose. Fatty acid composition was determined by gas chromatography, and three nitrogen fractions (total, noncasein, and nonprotein) were measured by Technicon Auto Analyzer. The differences, reference method minus infrared, for cows fed the conventional and protected lipid rations, were for fat .09 and .46%, for protein −.02 and −.08%, and for lactose .06 and .23%. Thus, agreement between infrared and reference methods was closer for cows fed conventional rations than for those fed protected lipid supplement. For cows fed the supplement, the low fat by infrared was attributed to an increase in the mean molecular weight of the fatty acids. Changes in fatty acid composition of milkfat when cows are fed protected sunflower-soybean supplement causes errors in estimation of fat by infrared analysis unless the instrument is calibrated specially for the milk.

Changes in the composition of bovine milk fat during milking

SummaryFat analyses were carried out on fore-milk and residual milk samples to elucidate the significance of the changes in fatty-acid composition of milk fat during milking previously reported by other workers. The levels of phospholipid in fore-milk samples per unit weight of fat were considerably higher than those of residual milk samples. The fatty acid composition of the triglyceride in fore-milk and residual milk samples was similar. These results suggest that the differences in fatty acid composition of milk fat collected during milking can be attributed to decreases in the relative amount of phospholipid-rich globule membrane associated with increasing globule diameter.

Influence of Dietary Fat and Short-Time Starvation on the Composition of Sow-Milk Fat

The influence of cottonseed oil and of linseed oil upon the fatty-acid composition of milk fat was each studied in one sow. Each oil was added to the basic diet in an amount of 6.3 % for two periods of the lactation. As cottonseed oil has a fatty-acid composition that is similar to that of the basic diet, the supplement with this oil will, in general, increase the same kind of fat in the diet. The linoleic-acid content in the milk fat will be nearly redoubled (11.7 % to 20.5 %) when the cottonseed oil is added. The supplement with linseed oil (of which linolenic acid constitutes about 58 %) to the food raised the linolenic-acid level in the milk fat from 1.1 % to 18.3 %. The increase of linoleic and linolenic acid is counterbalanced by a decrease of shorter fatty acids (G 14 and G 16 acids). The fatty-acid composition of the milk fat adjusts itself to the dietary changes within two or three days. By feeding a diet containing 16.7 % cottonseed oil to a sow, about 27 % linoleic acid was obtained in the sow’s milk fat. The influence of 30 hours of starvation upon the fatty-acid composition was studied in two sows. The content of G 18 acids rose during starvation and that of shorter acids (C14 and C16) diminished.