Milk Fat Products

The analysis of impact that breeding area, year of birth, calving season and interaction between breeding area and calving season have on milk and milk fat production in full lactations was performed in 241 Simmental cows, with 897 lactations born in period from 1998 to 2007 and distributed into three breeding areas (Čačak, Zlatibor and Rudno). According to applied model, analysis of the influence of paragenetic factors, imapct of breeding area and interaction of breeding area and calving season on the production of milk and milk fat in full lactation was very significant (P<0.01). The year of birth did not significantly impact (P>0.05) the production of milk and milk fat, while the calving season significantly impacted (P<0.05) the production of milk and insignificantly (P>0.05) the production of milk fat in full lactation. Coefficients of determination were very significant (P<0.01) and ranged from 0.431 (43.1%) in milk fat production to 0.500 (50%) in milk production.

Milk fat production is highly influenced by nutrition and rumen fermentation. Rumination is an essential part of the ruminant digestive process and can serve as an indicator of rumen fermentation. The objective of this research was to quantify variation in rumination time between and within dairy herds and test for relationships between rumination time and milk fat production and fatty acid (FA) profile as a proxy of rumen fermentation. Our hypothesis was that rumination may indicate disruptions to rumen fermentation and that cows that spent less time ruminating would have lower milk fat due to these rumen disruptions. Data were collected from 1,733 Holstein cows on 5 commercial dairy farms (4 in Pennsylvania and 1 in New York) of 200 to 700 head using 1 of 2 commercially-available rumination sensing systems, CowManager SensOor ear tags (Agis Automatisering BV) or SCR model HR-LDn neck collars (SCR Engineers). Rumination data were collected for 7 consecutive days leading up to a DHIA test, summed within day, then averaged to obtain mean daily minutes of rumination time. Milk samples from the DHIA test were analyzed for fat content by mid-infrared spectroscopy and for milk FA profile by gas chromatography. Rumination data were analyzed using multiple linear regression models. Rumination time was related to concentration of specific odd- and branched-chain and trans FA in milk but was not directly related to milk fat concentration. Rumination time also did not contribute to models predicting milk fat concentration after accounting for other cow-level variables. There was a linear relationship between trans-10 C18:1 and rumination time that was positive after accounting for the effect of farm (partial R2 of 2.97% across all data, 4.24% in SCR data, and 2.22% in CowManager data). Although rumination time was not related directly to milk fat, it was associated with differences in trans and odd- and branched-chain FA that have been demonstrated to change during subacute ruminal acidosis or biohydrogenation-induced milk fat depression, which may affect milk fat and other production variables. These associations suggest that further investigation into using rumination data from commercial systems to predict or identify the presence of these conditions is warranted.

The composition and functional properties of cow’s milk are of considerable importance to the dairy farmer, manufacturer, and consumer. Broadly, there are 3 options for altering the composition and/or functional properties of milk: cow nutrition and management, cow genetics, and dairy manufacturing technologies. This review considers the effects of nutrition and management on the composition and production of milk fat and protein, and the relevance of these effects to the feeding systems used in the Australian dairy industry. Dairy cows on herbage-based diets derive fatty acids for milk fat synthesis from the diet/rumen microorganisms (400–450 g/kg), from adipose tissues (<100 g/kg), and from de novo synthesis in the mammary gland (about 500 g/kg). However, the relative contributions of these sources of fatty acids to milk fat production are highly dependent upon feed intake, diet composition, and stage of lactation. Feed intake, the amount of starch relative to fibre, the amount and composition of long chain fatty acids in the diet, and energy balance are particularly important. Significant differences in these factors exist between pasture-based dairy production systems and those based on total mixed ration, leading to differences in milk fat composition between the two. High intakes of starch are associated with higher levels of de novo synthesis of fat in the mammary gland, resulting in milk fat with a higher concentration of saturated fatty acids. In contrast, higher intakes of polyunsaturated fatty acids from pasture and/or lipid supplements result in higher concentrations of unsaturated fatty acids, particularly oleate, trans-vaccenate, and conjugated linoleic acid (CLA) in milk fat. A decline in milk fat concentration associated with increased feeding with starch-based concentrates can be attributed to changes in the ratios of lipogenic to glucogenic volatile fatty acids produced in the rumen. Milk fat depression, however, is likely the result of increased rates of production of long chain fatty acids containing a trans-10 double bond in the rumen, in particular trans-10 18 : 1 and trans-10-cis-12 18 : 2 in response to diets that contain a high concentration of polyunsaturated fatty acids and/or starch. Low rumen fluid pH can also be a factor. The concentration and composition of protein in milk are largely unresponsive to variation in nutrition and management. Exceptions to this are the effects of very low intakes of metabolisable energy (ME) and/or metabolisable protein (MP) on the concentration of total protein in milk, and the effects of feeding with supplements that contain organic Se on the concentration of Se, as selenoprotein, in milk. In general, the first limitation for the synthesis of milk protein in Australian dairy production systems is availability of ME since pasture usually provides an excess of MP. However, low concentrations of protein in milk produced in Queensland and Western Australia, associated with seasonal variations in the nutritional value of herbage, may be a response to low intakes of both ME and MP. Stage of lactation is important in determining milk protein concentration, but has little influence on protein composition. The exception to this is in very late lactation where stage of lactation and low ME intake can interact to reduce the casein fraction and increase the whey fraction in milk and, consequently, reduce the yield of cheese per unit of milk. Milk and dairy products could also provide significant amounts of Se, as selenoproteins, in human diets. Feeding organic Se supplements to dairy cows grazing pastures that are low in Se may also benefit cow health. Research into targetted feeding strategies that make use of feed supplements including oil seeds, vegetable and fish oils, and organic Se supplements would increase the management options available to dairy farmers for the production of milks that differ in their composition. Given appropriate market signals, milk could be produced with lower concentrations of fat or higher levels of unsaturated fats, including CLA, and/or high concentrations of selenoproteins. This has the potential to allow the farmer to find a higher value market for milk and improve the competitiveness of the dairy manufacturer by enabling better matching of the supply of dairy products to the demands of the market.

Effects of Intraruminal and Intra-Abomasal Additions of Cod-Liver Oil on Milk Fat Production in the Cow

The objective of the study was to determine the effect of cassava pomace and protected soybean meal on dairy milk production and quality of mid lactating dairy cows. This research was conducted at Turen, Malang from January to April 2020. Twelve lactating Friesian Holstein dairy cows were divided into 2 groups so that each group consisted of 6, namely the control and treatment groups. The feed were a combination of forage and concentrate with a ratio of 35:65 in dry matter (DM). The control group received wet concentrate with DM content of 30.58%, 14.87% CP, and 75.06% TDN, while the treatment groups received concentrate with supplementation of cassava pomace 15% of DM ratio and protected soybean meal 45 g/l milk production. The variables observed were nutrient consumption, milk production and quality. Data between the two groups were analyzed using the Independent Sample T-test. The results showed that the addition of waste cassava and protected soybean meal increased (P<0.05) nutrient consumption (DM, OM, CP, CF, EE, and TDN). Milk production in the treatment group was higher (P<0.05) than control group (9.46 vs. 6.07 Ls/head/day). Milk protein production in the treatment group was higher (P<0.05) than control group (0.37 vs. 0.21 L/head/day). The content of milk protein and milk fat between the control and treatment groups was not significantly different (respectively 3.19 Vs 3.28; 4.46 vs 4.42 %). Milk protein and fat production in the treatment group was higher (P<0.05) than control group (0.21 vs 0.37; and 0.50 vs. 0.30 L/head/day respectively). The composition of glucose and blood urea in control and treatment dairy cows were not significantly different. In conclusion, giving cassava pomace and protected soybean meal to dairy cows during mid lactation increased nutrient consumption, milk production, milk protein production, and milk fat production but did not increase percentage of milk protein and fat. The treatment also did not affect blood glucose and nitrogen urea contents.

BackgroundIt is well known that feeding a high concentrate (HC) diet to lactating ruminants likely induces subacute ruminal acidosis (SARA) and leads to a decrease in milk fat production. However, the effects of feeding a HC diet for long periods on milk fatty acids composition and the mechanism behind the decline of milk fat still remains poorly understood. The aim of this study was to investigate the impact of feeding a HC diet to lactating dairy goats on milk fat yield and fatty acids composition with an emphasis on the mechanisms underlying the milk fat depression. Seventeen mid-lactating dairy goats were randomly allocated to three groups. The control treatment was fed a low-concentrate diet (35% concentrate, n = 5, LC) and there were two high-concentrate treatments (65% concentrate, HC), one fed a high concentrate diet for a long period (19 wks, n = 7, HL); one fed a high concentrate diet for a short period of time (4 wk, n = 5, HS). Milk fat production and fatty acids profiles were measured. In order to investigate the mechanisms underlying the changes in milk fat production and composition, the gene expression involved in lipid metabolism and DNA methylation in the mammary gland were also analyzed.ResultsMilk production was increased by feeding the HC diet in the HS and HL groups compared with the LC diet (P < 0.01), while the percentage of milk fat was lower in the HL (P < 0.05) but not in the HS group. The total amount of saturated fatty acids (SFA) in the milk was not changed by feeding the HC diet, whereas the levels of unsaturated fatty acids (UFA) and monounsaturated fatty acids (MUFA) were markedly decreased in the HL group compared with the LC group (P < 0.05). Among these fatty acids, the concentrations of C15:0 (P < 0.01), C17:0 (P < 0.01), C17:1 (P < 0.01), C18:1n-9c (P < 0.05), C18:3n-3r (P < 0.01) and C20:0 (P < 0.01) were markedly lower in the HL group, and the concentrations of C20:0 (P < 0.05) and C18:3n-3r (P < 0.01) were lower in the HS group compared with the LC group. However, the concentrations of C18:2n-6c (P < 0.05) and C20:4n-6 (P < 0.05) in the milk fat were higher in the HS group. Real-time PCR results showed that the mRNA expression of the genes involved in milk fat production in the mammary gland was generally decreased in the HL and HS groups compared with the LC group. Among these genes, ACSL1, ACSS1 & 2, ACACA, FAS, SCD, FADS2, and SREBP1 were down-regulated in the mammary gland of the HL group (P < 0.05), and the expressions of ACSS2, ACACA, and FADS2 mRNA were markedly decreased in the HS goats compared with the LC group (P < 0.05). In contrast to the gene expression, the level of DNA methylation in the promoter regions of the ACACA and SCD genes was increased in the HL group compared with the LC group (P < 0.05). The levels of ACSL1 protein expression and FAS enzyme activity were also decreased in the mammary gland of the HL compared with the LC group (P < 0.05).ConclusionsLong-term feeding of a HC diet to lactating goats induced milk fat depression and FAs profile shift with lower MUFAs but higher SFAs. A general down-regulation of the gene expression involved in the milk fat production and a higher DNA methylation in the mammary gland may contribute to the decrease in milk fat production in goats fed a HC diet for long time periods.

Influence of the metabolic state during lactation on milk production in modern sows

tAGPAT6 gene, which encodes for the enzyme 1-acylglycerol-3-phosphate O-acyltransferase 6, is a vital component in lipid metabolism and plays a significant role in milk fat production in dairy animals. The present study investigated the association of genetic variation within 5′UTR exons 1-1511, 3′UTR exons 1512-1723 of AGPAT6 gene in Deoni cows with milk production traits using PCR-SSCP method. The present investigation revealed three unique SSCP patterns, ‘1’, ‘2’ and ‘3’ in Exon 1 of the AGPAT6 gene. A total of two novel single nucleotide polymorphisms (SNPs) were identified in the coding region of Exon 1. Both the SNPs were found to cause silent mutation having significant (p≤0.01) association with fat percentage. The present study further aimed to investigate the relative abundance (%) of mRNA of AGPAT6 gene in PBMC of Deoni cows from the day of calving (0th day) to the 60th day post-partum using qRT-PCR. Expression levels of AGPAT6 were significantly elevated (p < .05) on the 30th, 40th, and 60th days postpartum relative to calving day, highlighting its pivotal role in extensive milk fat synthesis during lactation. The variation in expression, with a greater than 10-fold increase from day 0 to day 60, was predominantly driven by the lactation stage. Therefore, enhancing AGPAT6 gene expression in bloodstream signifies a valuable approach for the early identification of cows exhibiting increased milk fat levels and production during lactation. Additionally, the recognized polymorphisms could serve as genetic indicators for selective breeding.

Short-Interval Milking as a Physiological Technique. I. Effect of Frequent Milking with the Aid of Oxytocin on Milk and Milk Fat Production

Heritability, Phenotypic and Genetic Correlations Between Type Ratings and Milk Fat Production in Ayrshire Cattle1,2

Milk fat products (MFP), including butter and low‐fat dairy spreads, are a specific type of ready‐to‐eat food known as water‐in‐fat emulsions, in which the behavior of microbial foodborne pathogens such as Listeria monocytogenes is not clearly known. This study investigated the growth and survival of L. monocytogenes, and of Listeria innocua as a surrogate for L. monocytogenes, in these foods using challenge testing. Three commercial MFPs with various fat contents (butter, half butter and low‐fat dairy spread) and two samples of traditional churned butter with various water droplet sizes were artificially contaminated with Listeria. Total mesophilic microflora including lactic acid bacteria, pH and Listeria were monitored throughout the shelf life. The growth potential of Listeria was calculated in the course of the shelf life and remains below the limit value of 0.5 log cfu/g during the whole shelf life in any of the butter. However, the concentration of Listeria remained stable during the shelf life in the tested MFPs (commercial and churned) except in the commercial low‐fat dairy spread in which Listeria decreased gradually.Practical ApplicationsEuropean Union regulation No. 2073/2005 lays down the microbiological limit criteria for Listeria monocytogenes in ready‐to‐eat foods (RTE). According to this regulation, each RTE food has to be classified, with scientific justification, as able or unable to support the growth of L. monocytogenes during the shelf life. This challenge‐test study on milk fat products (MFPs) provided some useful data needed to assess the behavior of Listeria in these particular RTE food products. This study showed that while MFPs do not promote growth, they do support Listeria survival. Water droplet size seems to be a key parameter in preventing the growth of both microflora and Listeria. The study also showed that, in order to determine whether a given MFP supports Listeria growth or not, it is crucial to investigate the impact of the variations in physico‐chemical and microbiological parameters of each butter‐making process used by companies.

Arginine, one of the conditionally essential AA, has been reported to affect fat synthesis and metabolism in nonruminant animals by influencing adenosine monophosphate activated protein kinase (AMPK) in some organs. In dairy cows, the effect of Arg on milk fat production is not clear, and any potential mechanism that underlies the effect is unknown. We tested the hypothesis that Arg infusion would improve the production of milk fat, and explored possible mechanism that might underlie any effect. We used 6 healthy lactating cows at 20 ± 2 d in milk, in fourth parity, with a body weight of 508 ± 14 kg, body condition score of 3.0 ± 0, and a milk yield of 30.6 ± 1.8 kg/d (mean ± standard deviation). The cows were blocked by days in milk and milk yield and each cow received 3 treatments in a replicated 3 × 3 Latin square design, with each of the experimental periods lasting 7 d with a 14-d washout between each period. The treatments, delivered in random order, were (1) infusion of saline (control); (2) infusion of 0.216 mol/d of l-Arg in saline (Arg); (3) infusion of 0.868 mol/d of l-Ala in saline (the Arg and Ala treatments were iso-nitrogenous) through a jugular vein. On the last day of each experimental period, blood was sampled to measure insulin, nitric oxide, glucose, and nonesterified fatty acid, and the liver and mammary gland were biopsied to measure the expression of genes. Milk yield was recorded, and milk fat percentage was measured daily during each of the experimental periods. The yield and composition of fatty acid (FA) in milk was measured daily on the last 3 d during each of the experimental periods. The data were analyzed using a mixed model with treatment as a fixed factor, and cow, period, and block as random factors. The daily milk yield and milk fat yield when the cows were infused with Arg were 2.2 kg and 76 g, respectively, higher than that in control, and 1.8 kg and 111 g, respectively, higher than that in Ala. When the cows were infused with Arg they had higher concentration and yield of de novo synthesized FA, than when they received the control or Ala infusions, although milk fat percentage, daily feed intake, and the digestibility of nutrients were not affected by treatment. The serum concentration of nitric oxide and insulin were higher during Arg than during control or Ala, with no difference between control and Ala. In the liver, the expression of the genes coding for AMPK (PRKAA1, PRKAB1, and PRKAG1) and genes related to the oxidation of FA were higher during Arg than during control or Ala, whereas in the mammary gland the expression PRKAB1 was lowest, and the expression of genes involved in the synthesis of milk fat were highest, during Arg infusion. The results suggest the intravenous infusion of Arg enhanced the production of milk fat by promoting the de novo synthesis of FA and increasing milk yield.

The Effect of Roughage Intake upon the Fat Content of Milk

Factors Relating to Development of Spontaneous Oxidized Flavor in Raw Milk

Standards and labeling of milk fat and spread products in different countries