Physicochemical Parameters Of Milk Research Articles

Determining the influence of raw milk β-casein polymorphism on the efficiency of making soft cheese

One of the ways to increase the profitability of the cheese industry is the genetic selection of dairy cows to obtain milk with excellent cheese-capacity characteristics. The object of this study is the technology of fresh soft cheeses made by the acid-rennet and thermo-acid method from the milk of cows with different β-casein genotypes (A1A1, A1A2, A2A2). The subjects of research are the physicochemical indicators of raw milk from cows with different genotypes for β-casein (A1A1, A1A2, A2A2); as well as the yield of soft cheeses. The study has established that the physicochemical parameters of milk from cows with different β-casein genotypes are typical for fresh cow's milk. The study showed that with the acid-rennet method, the composition of cheeses from A1A1 milk was 51.60 %, 21.63 %, and 23.62 % of moisture, protein, and fat, respectively. A1A2 milk cheeses contained 50.70 % moisture, 20.96 % protein, and 25.12 % fat. A2A2 milk cheeses consisted of 52.50 % moisture, 20.70 % protein, and 23.71 % fat. With the thermo-acid method, cheeses from A1A1 milk were characterized by the moisture content of 55.13 %, proteins – 23.31 %, and fat – 20.21 %. A1A2 milk cheeses contained 58.13 %, 22.62 %, and 17.98 % of moisture, protein, and fat, respectively. A2A2 milk cheeses consisted of 54.03 % moisture, 22.33 % protein, and 22.25 % fat. The calculation of the production efficiency of soft cheeses from the milk of cows with different genotypes according to β-casein with the acid-rennet method of production is 119.3 % on average, which is more compared to milk A1A2 (by 4 %) and A2A2 (by 7 %). With the thermo-acidic method, the efficiency of cheese production from A2A2 milk is 107.5 %, which is higher compared to A1A2 milk (by 9 %) and A1A1 (by 5 %). The conclusions show that changes in the β-casein genotype in raw milk can affect the yield and quality of cheese, and therefore, the profitability of production

The biological integrity of natural poly-species symbiotic bacterial communities for the production of kefir: Basic aspects of the preservation

An integral step in kefir production technology is the use of kefir grains, but in some cases it is necessary to maintain their population at the plant. A convenient method is freezing, but with direct freezing, kefir grains lose activity and some microorganisms die off. The use of substances with cryoprotective properties can help preserve kefir grains under direct freezing conditions. The study has examined three environments that have the potential to protect the symbiosis of kefir grains under subcryoscopic conditions: skim sterile milk, gelatin and a sterile solution of 30 % sucrose, and one environment that is stressful – sterile distilled water. At previous stages of research, it was proven that sharp defrosting aggravates the stress phenomena of the bacterial community, in particular, promotes the death of surface lactococci which leads to dysbacteriosis of the symbiosis. The work used for the first time a periodic scheme for defrosting kefir grains in a protective environment; the methods of visual and organoleptic assessment have been applied, the studies of microbiological and physico-chemical parameters of milk after fermentation of kefir starter with kefir grains have been conducted. Milk changes have been carried out using the technology of cultivating kefir grains with daily passages. It is accepted that if based on a set of indicators kefir grains from the experimental groups within 7 days correlate with the indicators detected for the control group, which was not subjected to freezing, then it is accepted that the kefir grains have completely restored viability. If this does not happen, a conclusion is drawn that the symbiosis has not been restored. As a result of the research, the prospects for using the studied substances as protective media have been proven and the need to construct specialized cryoprotective media for direct freezing of kefir grains in order to create your own kefir culture banks has been substantiated. The approach will reduce the use of bacterial substitutes for kefir like direct fermentation starters.

An innovative form of the essential trace element copper for fortification of dairy products

Microelementosis is a disease associated with a deficiency of certain vital microelements. Today, there are ways to combat the lack of essential micronutrients. In this article, the mechanochemical synthesis of a triple copper-containing complex with ascorbic acid and L-isoleucine, an essential amino acid, was carried out. Examination of the sample by X-ray diffractometry showed that the sample has a trigonal crystal structure with space group P31c. As a result of computer quantum chemical modeling, the values of the difference in total energy, chemical hardness, energy of the highest occupied molecular orbital and the lowest unoccupied molecular orbital were determined. We determined the optimal option for the interaction of copper with vitamin C and L-isoleucine, where the binding occurs through hydroxyl groups attached to the C2 and C3 atoms of ascorbic acid, and through the carboxyl group and α-amino group of isoleucine. The sample was examined by IR spectroscopy and confirmed by computer modeling data. The stability of the resulting complex was studied depending on the technological parameters — pH, temperature and exposure time. Using the Greco-Latin square method, a matrix for planning a multifactorial experiment was compiled. An analysis of the dependence of the change in optical density (∆ D) on pH, temperature and exposure time showed that the pH of the medium and the temperature of the solution have a significant effect on ∆ D: an increase in the pH of the medium and the temperature of the solution leads to an increase in ∆ D. Exposure time does not have a significant effect to change the optical density value (∆ D). The parameters at which sample stability is observed correspond to the lowest values of ∆ D: pH = 3–8, t = 25–70, τ = 5–15. The effect of the concentration of a copper-containing complex on the physicochemical parameters of milk was studied. It has been established that the optimal concentration of copper ascorbate isoleucinate for fortifying dairy products is 0.005 mol/l or less. Next, an organoleptic assessment of the indicators of milk enriched with copper ascorbate isoleucinate was carried out. The analysis of the results showed that the organoleptic parameters (smell and taste) of milk enriched with ascorbate-isoleucinate of copper are 0.1 points higher than those of milk enriched with the inorganic form of the essential trace element copper and 0.3 points lower than that of the control milk sample.

Influence of humic acids on of cows milk productivity and indicators of milk quality and safety

The study was conducted to determine the effect of humic acids added to the diet of lactating cows on their milk productivity and physicochemical parameters of milk. The study was conducted on 14 Holstein cows of German breeding, which were fed 20 g/100 kg of live weight per day of an organic feed mixture containing 40.5% humic acids and 22% fulvic acids to their basic diet for 30 days. Milk samples were taken twice, before the use of the organic feed mixture and after 30 days of use. An increase in milk productivity by 5.8% was observed in 86% of lactating cows, the mass fraction of fat in milk increased A slight increase in milk fat content (p<0.1) is associated with an increase in this indicator in the milk of 72% of experimental cows from 0.2 to 0.92%. In the milk of the rest of the cows, the fat content of the milk did not change, but the average index for the group increased by 0.38%. The mass fraction of proteins after 30 days of using the organic feed mixture, an increase in the mass fraction of proteins in the milk of cows was noted on average for the group by 0.2% (р<0.05), with an average indicator for the group of 3.5±0.06% (3 ,12–4.2%). In the milk of 80% of the examined cows, the mass fraction of proteins increased from 0.12 to 0.9%, in 20% of the cows the mass fraction of protein in milk did not change, but the values corresponded to the basic norm (3.0%). An increase in average daily milk yield from 36.73±0.6 kg (35.43–38.9) at the beginning of the study against 38.85±0.19 kg (37.3–39.9; p<0.01) at the end of the experiment, which is 2.12 kg more and indicates a positive effect of humic acids on milk productivity of cows. The number of somatic cells in the milk of cows after a 30-day use of an organic feed mixture based on humic acids did not change and amounted to 104.78±19.09 thousand/cm3 (20.0–218.0), against 104.47±23, 5 thousand/cm3 (11.0–246.0) at the beginning of the study. In the milk of 28.5% of cows, at the end of the study, a slight decrease in the number of somatic cells was noted from 35 to 55 thousand/cm3, in the milk of 21.4% of cows, the number of somatic cells increased slightly from 19 to 74 thousand/cm3, which corresponds to the physiological norm . Milk urea nitrogen is used to assess the energy-protein balance in feed; a reduced value at the end of the study ranged from 7.1 to 18.5 mg/100 ml, indicating a crude protein deficiency in the diet. Key words: humic acids, number of somatic cells, mass fraction of fat, mass fraction of proteins, lactose, milk urea nitrogen, milk productivity.

Comparative Study of Some Physicochemical Criteria of the Milk of Goats Raised in the Touggourt Region, Algeria

The creation of the goat sector in Algeria and government subsidy have led to the appearance of specialized goat breeding systems and dairy production. Goat's milk is a popular food in the arid and semi-arid regions of Algeria. This food contributes effectively to balance and enrich the nutrition of the populations of these regions. The present study aim to contribute to the physicochemical characterization of goat milk from three breeds (Alpine, Arbia and the Cross breed) reared in the research station of Touggourt, by analyzing and comparing the physicochemical properties of these milks: pH, density, titratable acidity, fat, dry matter, non-fat dry matter and humidity content in various milk samples. A total of eighty-one samples of milk coming directly from the udders of goats of these three breeds (n=81) were collected in 2022. The samples are: (n1=60) from goats of the Alpine population, (n2= 9) from the Arbia breed and (n3 =12) from the cross breed. The parameters determined varied according to the day of sampling and the breed of goat from which the milk was obtained. The physicochemical quality of the milk varied from one breed to another. The Alpine goat showed a superiority in the Fat content (37.27 ± 4.11 g/l), in dry matter (115 ± 1.17 g/l) and in defatted dry extract (77.80 ± 9.38 g/l ), more over the Arbia breed marked a superiority in pH (6.75±0.04), and humidity (90.46 ± 0.10%), and the Cross breed in density (10 27± 1.075). and the Acidity (17.33±0.45 °D). This allows us to conclude that breed has an effect on the physico-chemical parameters of milk.

The effect of the feed additive "Relikt A®" on the blood and milk parameters of newborn cows

This work is devoted to the study of the effect of the 4% feed additive "Relikt A®", which includes a complex of humic substances, on the morphological and biochemical parameters of blood, the physico-chemical composition of milk, namely, the content of milk protein, fat (their ratio), dry fat-free milk residue, density, acidity and conductivity. As a result of the studies on the 30th day, it was found that with the introduction of a 4% feed additive "Relict A®" into the diet at a dose of 200 mg/kg of live weight, the total protein in the blood serum of the experimental group exceeded the control values by 12,06% (pЈ0,01**), albumin - by 7,86% (рЈ0,05*), globulins - by 14,87% (рЈ0,01**), urea - by 21,33% (рЈ0,05*), calcium - by 17,41% (pЈ0.05*), calcium to phosphorus ratio - by 42,97% (pЈ0,001***), magnesium - by 8,14% relative to control values. According to the physicochemical analysis of milk after 14 days of the experiment, it was noted that the milk protein in the experimental group is higher than the control values by 8,00% (pЈ0,05*), the ratio of fat to protein is lower by 31,90% (pЈ0,05*). On the 30th day of the experiment, it was noted that the milk protein of the experimental group of animals is higher than the control ones by 8,36% (pЈ0,05*), SOMO (dry skimmed milk residue) - by 8,39% (pЈ0,05*), acidity is lower by 11,35% (рЈ0,01**). The introduction of the "Relikt A®" feed additive into the diet at a dose of 200 mg/kg optimizes the biochemical processes of the body of cows in the early period after calving, reduces the risk of ketosis and hypocalcaemia, and ensures the absorption of dietary nutrients, which is expressed in the corresponding physicochemical parameters of milk.

Influence of feeding level on the formation of milk productivity of dry cows

The materials of the publication demonstrate the results of scientific research conducted on Simmental cattle in the farm “Pchany-Denkovych” Stryy district of the Lviv region. The research is based on optimizing the normalized feeding of cows during the start-up period. The diets of experimental animals include low, medium, and high levels of energy nutrition according to detailed standards. The study was conducted on three groups of Simmental cows with eight heads each. The analysis of the obtained results showed that the different levels of energy nutrition of experimental animals did not significantly affect the hematological parameters; their level was within physiological norms for healthy animals. Estimating the intensity of metabolic processes in the body of dry cows was carried out based on the contents of the scar. There was a probable increase in the number of amylo- and cellulolytic bacteria, the number of which prevailed (the second and third groups) in comparison with the control by 1.42–2.32 and 2.32–2.53 million/ml. A similar pattern was observed for the number of proteolytic bacteria. The increase in these populations of microorganisms contributed to their enzymatic activity, which led to a probable increase in the number of LVH, which are precursors of milk fat. According to the indicators of live weight gain during the dry season, animals of the second and third groups had an advantage. Physicochemical parameters of milk were also better in these groups of cows; the higher the level of nutrition, the higher the fat, protein content in milk. A similar analogy is observed for the dynamics of the live weight of calves, which is directly proportional to the level of feeding cows during the dry season. For four months, the calves of the experimental groups had higher growth energy (6.7–10.5 % compared to the control). The control over the level of milk productivity of cows after calving was carried out according to control milk yields, which showed that the hopes for lactation in the experimental groups were 7.2–8.0 % higher than in the control group. This is because the animals of the experimental groups, due to the higher level of feeding according to detailed standards in the dry season, deposited more nutrients in the body and thus provided a higher level of milk productivity. Therefore, the conducted research gives grounds to recommend the farm to use high and medium levels of energy nutrition for cows during the dry season.

EVALUATION OF MILK QUALITY PARAMETERS FROM COWS WITH MASTITIS

The social significance of mastitis is manifested in the fact that the causative agents of mastitis in cows can cause disease in humans. Since the leading role in mastitis pathology belongs to streptococci and staphylococci, it is they who most often enter the milk. The purpose of the research was to establish the frequency of occurrence of subclinical mastitis in cows, its effect on the physicochemical parameters of milk with the determination of the species composition of the microflora of milk in cows with subclinical mastitis with the development of a method for its diagnosis in the early stages of the development of inflammation of the mammary gland. The work is based on the results of analytical analysis of the literature, a comprehensive clinical, instrumental and laboratory study of lactating cows with mastitis. Studies have established that the disease of the udder in cows with mastitis at the beginning of lactation has a certain seasonal nature and its main peaks occur in March-May and September-November. During these months, from 2.5 to 4.1 % of cows with mastitis from the total number of the farm were identified. It has been established that with mastitis there is a change in the physicochemical parameters of milk: an increase in the number of somatic cells up to >1500 thousand/cm3; an increase in the pH of the milk to 7.3, which is associated with the breakdown of milk proteins to ammonia, and an increase in the electrical conductivity of milk to 7.54 mS/sm, due to the entry of sodium and chlorine ions into milk from the blood. The task in developing a method for diagnosing mastitis in cows was to diagnose the disease at the early stages of the development of inflammation of the mammary gland and facilitate complex studies. This method consists in studying the composition of a biological fluid, which is applied to a glass slide in the form of a drop of milk from the examined quarter of the udder, dried to obtain a solid medium structure, and examined under a light microscope.

Effect of tomato dregs supplementation on the quality of bovine milk production in the Holstein breed

This work focused on the one hand on the characterization of tomato by-products (Solanum lycopersicum L. 1753) and on the other; on the supplementation of tomato spent grain in the diet of Holstein breed cows and its effect on the volume and quality of milk. A comparative study between two lots; one contains dairy cows fed through a diet without tomato spent grain, the second batch fed with tomato spent grain. The physicochemical analyzes of tomato spent grain focused on the water content, dry matter, mineral matter, total proteins, fat, defatted matter, Phosphorus, Calcium and vitamins A and Vitamin E. We note that tomato spent grain is very rich in vitamin A and E as well as in calcium and phosphorus and that it also has a low fat and protein content. According to the results obtained, we notice an improvement in the following physicochemical parameters of milk: a significant increase (p < 0.001) in density which goes from 1026 ± 1.97 to 1028 ± 2.14, a significant increase (p < 0.01) in fat which goes from 40.74 ± 7.07 to 43.94 ± 8.45, and a significant increase (p < 0.001) of the dry extract which goes from 124.56 ± 11.31 to 148.7 ± 29.88. A significant increase (p < 0.001) in the average daily volume of milk is observed in the batch supplemented with tomato spent grain (13.73 ± 3.47 l/d) compared to the batch not supplemented with tomato grain (11.12 ± 3.00 l/d). The statistical study reveals that there is a relationship between the duration of supplementation and the continuous improvement of parameters: density (p < 0.001); dry extract (p < 0.001); degreased material (p < 0.001).

QUALITY OF RAW MILK AND ITS FATTY ACID COMPOSITION

The study of the influence of the season on the organoleptic and physicochemical parameters of milk is still relevant. In addition, the ratio of fatty acids in the milk of cows characterizes the level of their feeding and the study of these indicators is relevant given the prevalence of adulteration of milk and dairy products with vegetable oils. The aim was to study individual indicators of raw milk quality depending on the season and its fatty acid composition. The material for the study was prefabricated chilled raw milk obtained at different times of the year on the dairy farm of NULES of Ukraine "Agronomic Research Station". The research was conducted in the accredited Ukrainian Laboratory of Quality and Safety of AIC NULES of Ukraine. Organoleptic, physicochemical, sanitary and hygienic were determined by generally accepted standard methods. The fatty acid composition of milk was investigated by gas chromatography. Extraction of lipids from milk was performed by the method of Folch. Analysis of LCD methyl esters was performed on a Trace GC Ultra gas chromatograph (USA) with a flame ionization detector. Identification of fatty acids was performed using a standard sample Supelco 37 Component FAME Mix. Quantitative evaluation of the fatty acid spectrum of milk fat lipids was performed by the method of internal normalization with their determination in percent. The study was performed in 2 parallels. Statistical processing of experimental data was performed by conventional methods of variation statistics. The probability of the difference in indicators was assessed by Student's t-test. Differences between the compared indicators were considered significant at the significance level P≤0.05. Studies have shown that milk organoleptic and physicochemical parameters of raw milk vary depending on the season. In terms of microbiological indicators, the milk corresponded to the first grade, although in winter, according to other indicators, it could be attributed to the extra, or at worst, to the highest grade. In addition, in winter the content of saturated fatty acids in milk increases. The content of unsaturated fatty acids increases in summer and autumn due to the presence of green mass and corn silage in the diet of cows. The obtained results can be used as a basis for preparing a diet to obtain milk with optimal content and ratio of fatty acids, which can become competitive in the market of raw milk to produce milk and dairy products of improved chemical composition, dietary, functional products, baby food. Key words: raw milk, quality, sanitary and hygienic indicators, fatty acids

Influence of the season and lactation on the milk composition of goats-producers of biosimilar human lactoferrin

The seasonal variability of the physicochemical parameters of milk of both ordinary goats and goats producers of a biosimilar human lactoferrin has been established. The average values of the mass fraction of fat, protein, lactose, nonfat milk solids, density index in the second and third quarters were lower than in the first and fourth quarters. At the same time, the difference between the spring-summer and autumn-winter periods in the mass fraction of fat was 25%. In the mass fraction of protein, lactose, nonfat milk solids, density it was 5–7%. Comparative analysis of milk from goats-producers of a biosimilar human lactoferrin of various lactations revealed a number of changes in the physicochemical composition of raw materials in comparison with non-transgenic animals: an increase in the mass fraction of protein by 4–6% (P˂0.05), of lactose by 2–6 (P˂0.05), nonfat milk solids by 1–6, density by 2–5% (P˂0.05), freezing temperature by 5 and a decrease in the mass fraction of fat by 5–8% (P˂0, 05). At the same time, the indicators of active and titratable acidity of milk were similar in all groups of animals. At the same time, the concentration of human lactoferrin in the milk of producers of the second and third lactation had almost identical seasonal changes in the increase and decrease in the synthesis of lactoferrin in the mammary gland during the year: in the first quarter – 2.88 and 2.97 g/l, in the second – 4.76 and 4.63, in the third – 7.44 and 7.55 and in the fourth – 7.97 and 6.72 with an average annual value of 5.84 and 5.72 g/l, respectively.

АНТИОКСИДАНТНАЯ АКТИВНОСТЬ НАТИВНОГО МОЛОКА И ЕГО БЕЛКОВЫХ ФРАКЦИЙ

Compounds with antioxidant properties act as stabilizers of biological membranes and prevent the development of free-radical chain processes that lead to the development of severe diseases. Cow’s milk shows antioxidant activity due to whey proteins. Heat treatment used in dairy production technology can inhibit the antioxidant properties of milk proteins. Preserving the natural properties of milk is an urgent task. (Research purpose) The research purpose is in studying the antioxidant activity of raw milk and protein fractions isolated from it with optimal preservation of the activity of whey proteins. (Materials and methods) Authors received raw milk from an individual farm in the Moscow region. The physicochemical parameters of milk and whey were assessed by standardized methods; the fractional composition of proteins was assessed by high-performance liquid chromatography; and the antioxidant activity (total content of water-soluble antioxidants) of milk and protein fractions isolated from it assessed by amperometric method. Milk proteins were coagulated using rennet and calcium chloride. Protein fractions were separated by centrifugation (15,000 revolutions per minute) for 90 minutes. (Results and discussion) The article presents the physical and chemical parameters of raw whole and skimmed milk. The fractional composition of native serum proteins with a predominance of beta-lactoglobulin was studied. The method of milk protein isolation by rennet-calcium method was worked out at a minimum temperature of 38-40 degrees Celsius. (Conclusions) The article presents the composition of raw milk. The article presents the developed optimal conditions for isolation of native proteins from raw skim milk. The antioxidant activity of raw milk, casein fraction and whey was assessed. To maximize the preservation of the antioxidant activity of biologically active whey proteins, it is necessary to reduce the generally accepted pasteurization temperatures of milk (75-95 degrees Celsius), while at the same time searching for new methods of decontamination of milk from foreign microflora.

ВЛИЯНИЕ ПРЕМИКСОВ И БОЛЮСОВ НА ПРОДУКТИВНОСТЬ И КАЧЕСТВО МОЛОКА КОРОВ

In a comparative aspect, the result of providing cows with minerals and vitamins through boluses and premixes is presented. The studies were carried out in the Republic of Tatarstan in 2019 on three groups of cows, 15 animals each. The first (control) group of cows received a feeding ration with the P60-1/C premix during the dry period, and after calving - with the P60-3 premix for 60 days. Cows of the second and third groups on the first day of the dry period received Bolus-1 and Bolus-2, respectively (2 boluses) once, and after calving - a ration with P60-3 premix for 60 days. The experiment was carried out according to the method of A.I. Ovsyannikov. The results were processed according to A.N. Plokhinsky. Milk production was monitored daily for 60 days. Physicochemical parameters of milk were determined using the device “Laktan 1-4” on the 60th day of lactation. In animals that received boluses, milk production in terms of basis fat was higher on average by 3.7%. The increase in productivity in cows of the second group was significant relative to that in cows of the first group (p &lt;0.05). When boluses are used in animal feed rations, the most effective use of diet components is noted: in the second and third groups, 4.17 and 4.16% less metabolic energy was spent on the production of 1 kg of milk of base fat content and by 3.06 and 3.05 % respectively less crude protein. The largest mass fraction of protein was in the milk of cows in the control group - 2.92% (p &lt;0.001), and the mass fraction of fat - in cows receiving Bolus-1 (3.88%). The milk of cows receiving Bolus-2 was characterized by the highest density (30.58 ° A, p &lt;0.05). The use of premixes and boluses did not affect the SNF content in milk

Antimicrobial activity and therapeutic efficacy of thiacycline in subclinical mastitisin sheep

Relevance. The work is devoted to the results of studying of the antimicrobial and therapeutic efficacy of the drug thiacycline in subclinical mastitis in sheep. The aim of our research еsеwas to study the antimicrobial activity and therapeutic efficacy of thiacycline in subclinical mastitis in lactating ewes.Methods. The study of antimicrobial activity was carried out by the method of serial dilutions in a liquid nutrient medium, on the basis of the Caspian zonal NIVI in the laboratory on the study of diseases of non-infectious etiology of farm animals. The therapeutic efficacy of thiacycline was studied in the SEC "Bukhti" of the Gunib district of Dagestan Republic on ewes of the Dagestan rock, aged from 3 to 5 years, with subclinical mastitis, in the amount of 51 heads. Animals on the basis of analogues were divided into two groups: experience (n = 26), control (n = 25). The animals of the experimental group were treated with thiacycline, the drug was administered intramuscularly, once a day, in dose 0.1 ml/kg. The test combination drug thiacycline developed by VIC. The control group was treated with bicillin-3, in dose 600,000 units per head, with an interval 72 hours.Results. The complex antibacterial drug thiacycline has a wide spectrum and high antimicrobial effect against museum strains and potential causative agents of sheep mastitis. The therapeutic efficacy of thiacycline in the treatment of subclinical mastitis in sheep – 97.0%, which is on 13.0% higher compared to bicillin-3. On the 7th day after the last administratin of preparation all the physicochemical parameters of milk corresponded to the physiological norm.

CONTRIBUTION TO THE STUDY OF THE PHYSICOCHEMICAL CHARACTERISTICS OF BOVINE MILK IN THE TLEMCEN REGION

The objective of this work is to carry out a comparative study through the main factors (individual, breed, age and region) having a direct effect or by interaction on the physicochemical parameters of th milk produced by 3 types of cows, local (BLL), imported (BLI) and crossed (BLC) which are reared b the same extensive farming system in the western region of Algeria. A total of 88 dairy cows, 55 BLLs, 17 BLIs and 16 BLCs selected at the beginning of lactation were followed regularly for a period of three months (March to May). At the same time, milk samples are taken for each cow and then they are sent for analysis at the laboratory. The physicochemical parameters of milk analyzed as well as milk production showed a very varied degree of influence with respect to breed and age.

Effect of somatic cell count on dairy products: a review

Somatic cells are the most essential factors naturally present in milk, and somatic cell count (SCC) is used as an indicator of monitoring mastitis incidence in the herd and also to assess the quality of milk. In addition, SCC is frequently used to determine quality payments to dairy producers. The SCC is directly related to get maximum milk production from individual cow and a lower SCC indicates better animal health, as somatic cells originate only from inside the animal's udder. SCC monitoring is important because as the number of somatic cells increases, milk yield is likely to fall, primarily due to the damage to milk-producing tissue in the udder caused by mastitis pathogens and the toxins they produce, particularly when epithelial cells are lost. Keeping low SSC will allow good quality more raw milk and provide a better product to milk processors whether used as fluid milk or converted to milk based products. Somatic cells containing lipolytic and proteolytic enzymes lead to degrade major nutrients fats and proteins, respectively. Elevated SCC is related to udder inflammation, which leads to alter the normal microbial count and physicochemical parameters of milk, as well as the quality of heat treated fluid milk and milk based product. The objective of this review is to discuss on the SSC and endogenous enzymes released from somatic cells in raw milk as well as effect of somatic cells count and their endogenous enzymes in processed milk and milk based products.Asian J. Med. Biol. Res. March 2017, 3(1): 1-9

Diet and bioclimatic conditions on production and milk quality

It was aimed to analyze the productive performance of lactating cows on isoprotein fed diets, at differentiated environmental conditions. Eight Holstein cows were used, grouped in two 4 × 4 balanced Latin squares design. The treatments were evaluated in 2 × 2 factorial designs: sources of roughage (corn silage – CS plus concentrate, and the combination of corn silage with sugarcane - CSSC, 1:1 on DM, plus concentrate) and distinct environment (with= WS and without= OS, fan and nebulizers system= Sfn). The estimation of dry matter intake (DMI), productive performance and physicochemical parameters of milk were evaluated. There was no interaction effect of environment factors and source of forage. There was signiA cant effects for the source forage factors, where the DMI for the CSSC based diet was higher than the CS based diet in the effect of forage (4.22 vs. 4.06% BW, and 22.3 vs. 21.7 kg/d, respectively, P≤0.05), but with similar milk production correcting 3.5% fat (23.01 vs. 22.62, CSSC and CS; 22.85 vs. 22.78 kg/day, WS and OS, respectively, P≥0.05). The feed efA ciency and conversion was similar in both factors (102.8 vs. 104.7% and 0.99 vs. 1.0, CSSC and CS; 102.5 vs. 104.9% and 1.0 vs. 0.99, WS and OS, respectively, P≥0.05). The beneA t-diet cost ratio was higher for CS-based diet than for CSSC (7.44 vs. 6.97, P≤0.05). There were effects only in the forage factor for CP milk (3.26 vs. 3.23%, P≤0.05), lactose (4.54 vs. 4.49%, P≤0.05) and urea nitrogen in milk (23.21 vs. 20.71 mg/dL, P≤0.05) and the superiority arising from the CSSC-based diet in comparison to the CS diet. There was higher for T and THI (28.1 vs. 23.6°C and 75.1 vs. 71.1, respectively, P≤0.05), and lower RH to 2:00 pm (47.7 vs. 64.5%, P≤0.05). The linear score showed negative correlations with DMI, milk production, lactose and urea nitrogen (-0.36, -0.69, -0.44 and -0.32, P≤0.05, respectively). The use of the diet based on CSSC proposed increases in DMI and milk quality without affecting production, but with smaller beneA t-diet cost ratio. The use of the environmental cooling system did not improve the production, qualitative parameters of milk and thermal comfort of dairy cows under the conditions evaluated.

Application of ozonated water for sanitizing cow teats and its influence on quality of milk

This study evaluated the efficiency of ozonated water compared with chlorhexidine to disinfect teats of cattle and their influence on milk quality. 48 cows were separated in 2 groups of sanitation: (I) using ozonated water at 2 mg.L -1 for 30s and (II) using 2%(v/v) chlorhexidine for 30s (standard methodology of disinfection). Before and after sanitation, swabs of teat were collected for carry out microbiological analysis. Additionally, after teats sanitation, the milking was performed and the obtained milk were evaluated by microbiological and physico-chemical parameters. The number of decimal reductions (NDR) reached after ozone sanitation was 2.52, 2.09 and 1.50 for aerobic mesophilic, Staphylococcus sp. and Enterobacteriaceae, respectively. The use of chlorhexidine promoted NRD of 2.38 (aerobic mesophilic), 2.04 ( Staphylococcus sp.) and 1.16 (Enterobacteriaceae). Therefore, no significant differences were found between NRD caused by chlorhexidine and ozonated water. Moreover, no significant differences were observed in the psychrotrophic and aerobic mesophilic counts of the milk obtained after teats sanitation with ozonated water and chlorhexidine. Furthermore, it was observed that only samples obtained from cows treated with chlorhexidine showed the presence of Enterobacteriaceae. There were no changes in the physico-chemical parameters of milk obtained after both treatments. Thus, the ozonated water is a potential substitute of chlorhexidine for cows teats sanitation, resulting in similar microbiological reductions without risks of bacterial resistance development and waste generation.

Impact of good hygiene practices in milking over microbiological and physicochemical quality of raw refrigerated milk

Normative instruction no 62 brought new standards to be followed by producers, proceeding to continue the improvement of milk quality in progress since Normative instruction no 51. However quality improvement of milk did not occur as fast as expected. The aim of this work was to evaluate the impact of good practices on milk quality in 49 dairy farms located in Ivaipora/PR, through collective lectures and training courses. A reduction of 88,05% in Total Bacterial Count (TBC) in 28 (57,15%) dairy farms that implemented the good practices was observed. From those farms, 23 (47,93%) presented TBC bellow maximum of 750.000 CFU/mL as required by legislation at the period of analysis, with average counts of 166.826,1 CFU/mL. As for Somatic Cell Counts (SCC), 83,57% of all farms began to produce milk according with the standard set to this item at the time of analysis. Significant variations were not observed in physico-chemical parameters of milk after practices implementation. Implementation of the proposed practices was sufficient to produce milk according with standards established by legislation.