RELATION BETWEEN THE AMOUNT OF SOMATIC CELLS AND THE LACTOSE IN THE COW MILK OF ORGANIC FARMING ORIGIN

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1 RELATION BETWEEN THE AMOUNT OF SOMATIC CELLS AND THE LACTOSE IN THE COW MILK OF ORGANIC FARMING ORIGIN MIROSLAV SKRIVANEK 1, KVETOSLAVA SUSTOVA 2, GUSTAV CHLADEK 1, ZDENEK HADAS 1 1 Department of Animal Breeding 2 Department of Food Technology Mendel University in Brno Zemedelska 1, Brno CZECH REPUBLIC farmams@seznam.cz Abstract: The aim of this study was to evaluate the relation between the number of somatic cells and the amount of lactose at a dairy herd of cattle managing in the organic farming mode. Individual samples of milk were monitored for a period of one year, when the samples were taken once per month and underwent analyses in the Brno Tuřany laboratory. Apart from the somatic cells count (SCC) (thousands/ml) and lactose (L) in milk, we monitored the milk yield (kg), the contents of fat (%), proteins (%), urea (mg/100ml) and free fatty accids (FFA) (mmol/100g of fat). After the evaluation it is clear that the relation between the number of somatic cells and the amount of lactose is in mutual negative correlation. The results can be used in a zootechnical practice when filtering off the results of non-infectious mastitis. Key Words: organic farming, milk, somatic cell, lactose, mastitis INTRODUCTION Currently in a dairy technology the most widely used type of milk is the cow milk which is a product of a mammary gland of domestic cattle (Bos primigenius f.taurus) (Samková 2012). It is a complex food, when most of the nutrients contained in milk do not act in isolation but in cooperation with a variety of other components. Further on the domestic cattle milk contains many inorganic substrates and biocatalysts (Vorlová et al. 2015). A complex system, such as raw cow milk, contains apart from basic components, such as water, milk fat, proteins, milk sugar and mineral substances, also a variety of other compounds of organic and inorganic origin. Raw cow milk being an important material for milk technologies contains more than a hundred substances with different chemical and physical features (Semjan 1987). The essential, and indeed the only component of carbohydrates in cow milk is lactose (C₁₂H₂₂O₁₁). Carbohydrates, such as glucose, galactose or oligosaccharides, are present in raw cow milk in negligible quantities (Samková 2015). Lactose is present in milk in the range of %. It is a disaccharid with low sweetnes and good digestibility for a human being (Navrátilová et al. 2012). Other nonseparable components of cow milk, besides others, are also somatic cells. Their number is an important value of hygienic quality. The number of somatic cells in milk (SCC) indicates the physiological balance and state of health of the dairy cow and its mammary gland. SCC is one of the basic criteria for national and international regulation of milk quality. According to the Regulation of European Parliament and Council No. 853/2004 the upper hygienic limit for purchase of raw cow milk was established for SCC at the number of in 1 ml of a pool sample of milk (Samková 2015). MATERIAL AND METHODS Characteristics of the Farm and the Herd Reared in Organic Farming Branná, the organic farm, has been kept under the organic farming mode since The main focus of the farm is a livestock production and only partially a crop production. The organic farm produces bulk feed itself, that is hay, haylage and silage, to provide feed supplies for animals. In 273 P age

2 livestock production the farm breeds cows with market production of milk and cows without market production of milk (Hereford a Galloway breeds). The dairy herd consists of Czech Pied cattle breed. Summer ration of dairy cows (from 15/5/2015 to 20/10/2015) is provided by the animals grazing on surrounding lands. The walking distance for the dairy cows to the pasture is up to one kilometer. After milking the dairy cows are served with energetic feed in a form of a mixed ration of meal and silage. At the farm the night feast is also applied. In winter months the animals are fed on conserved forage, grass silage and hay. From organic mill operation the farm purchases mill by-product, grits and bran to fill the energy compound of the feed ration of the animals bred. The farm operates a newly reconstructed parlor, a half-size version of herringbone type 1 x 11 places for dairy cows; it is a semi-automatic milking technology. The milked milk is then pumped off through a mechanical filter into a tank, where being sprayed on cooled walls of the tank it is cooled onto C. Milking takes place twice per day, that is always in the morning at 3:30 a.m. and in the afternoon at 15:30. Sets of Milk Samples For the analyses, individual samples of raw milk of dairy cows were used. At the monitored farm the milk of dairy cows was led from the milking unit to milk metres behind which drip collecting vessels were temporarily installed, being able to prepare a milk sample from the entire time of milking one animal. In total, on average 105 individual milk samples were collected per month. Milk samples were collected once per month. Collections were conducted at regular intervals in the range of 14th 20th day of a month. Further on the milk was cooled and transferred to subsequent analyses. Milk of the dairy cows which milk was anyhow nonstandard (increased number of somatic cells, medically treated dairy cows, dairy cows after calving, milk with blood), was collected with a clean ladle from milking cans allotted for milking nonstandard milk. Analytical Methods Analyses of milk were carried out in an accredited laboratory (according to CNS EN ISO/IEC 17025:2005) for milk analysis in Brno Tuřany (number of the test laboratory , number of the certificate 750/2015) according to methods: Determination of milk composition (fat, protein, lactose), urea and freezing point by infrared spectroscopy SOP 01, CNS :1999. Determination of number of somatic cells by fluoroopto-electronic method SOP 02, CNS EN ISO :2007 Lactose: this is a quality parameter of milk. The amount of lactose in analyzed milk of the dairy cows is determined by infrared absorption analyzer which measures the amount of light that is absorbed by hydroxil groups. It is an indirect method of measurement (determination of lactose monohydrate). The amount of lactose (% of monohydrate) is reported in g/100g ( Somatic cells: the amount of somatic cells in milk is a quantitative indicator. The number of somatic cells in raw cow milk is determined by fluoro-opto-electronic method. At this procedure the somatic cells are particals that have a minimum intensity of fluorescence due to staining with fluorescent dye. In a flow cytometer the dyed somatic cells create an electrical impulse and it is registered. The number of somatic cells is reported in thousands in 1 ml of milk. At samples of milk with high number of SCC, a bacterial examination of the presence of mastitis pathogenes was performed. A control measurement of SCC was performed also directly at the organic farm. For the control measurement the MT05 device of Slovak producer PISOFT was used. This device is used for immediate detection of somatic cells count in fresh milk. It is used when monitoring the decline of somatic cells count at dairy cows after calving (the end of a colostric period), when daily controlling the pool samples of milk etc. To the measured milk an agent is added, which affects somatic cells in milk and this way it changes the milk viscosity so that the rate of the viscosity change is directly proportional to the somatic cells count in the milk of the dairy cow. For this accurate viscosity measurement a special ball in the device is used. The ball moves in an inclined glass tube by an angle of 25 according to the milk viscosity. The device analyzes a sucked milk sample in a way that in the glass tube with the sample a metal ball moves downwards for specific time, after that the tube automatically offsets horizontally and 274 P age

3 on the scale the values of somatic cells count can be read. The measurement time of one sample is 30 seconds. Statistical Evaluation To analyze the parametres the statistical software R was used. Basic statistical parametres such as geometric mean and standard deviation were calculated. To describe the relations between the number of somatic cells and lactose, the method of constructing a biplot was used. These relations were described for all the analyzed compounds of milk (milk yield (kg), fat (%), protein (%), lactose (%), somatic cells (SCC), (tis./ml), urea (mg/100ml), free fatty acids (FFA) (mmole/100g fat). RESULTS AND DISCUSSION The number of somatic cells in milk was evaluated in orginal values. The amount of lactose was evaluated in a logaritmically transformed form. Selective standard deviations (SSD) (observation deviations from selective average) were counted from logaritmical data. Achieved values of milk yield are shown in the Table 1 and the Figure 1. The average yield is relatively stable, that is through all the monitored period. Low yield is caused by feeding in an organic farming system, location of the farm in a mountain region, and the breed bred (Czech Pied cattle). The slight increase was observed in the months of June and October. This can be attributed to the pasture maturity of overgrowing areas for pasture in spring and after summer mowing. Table 1 Basic statistic characteristics of milk yield and milk compounds month milk yield (kg) milk yield SSD SCC (tis./ml) SSD of SCC lactose (%) lactose SSD I II III IV not collected V VI VII VIII IX X XI XII Figure 1 Development of milk yield in average of the reference year 275 P age

4 Figure 2 Values of somatic cells count (SCC) (thousand/ml) Achieved values of SCC are shown in the Table 1. and the Figure 2. The analysis of the somatic cells count in the organic farm milk proved an increase over the permitted norm (400 thosand/ml) in the months of March and September. High increase of somatic cells count in milk indicates inflammations of mammary glands, so called mastitis at dairy cows bred. At the microbiological analysis of the milk the most spread disease agents were found as Streptococcus uberis a Streptococcus agalactiae. At selected dairy cows antibiotic treatment was started. After an examination more serious cases of mastitis were selected off the herd for slaughter. Figure 3 Values of lactose amounts (%) Achieved values of lactose are shown in the Table 1. and the Figure 3. In the analyzed milk a significant decrease of lactose in milk occurs from the month of April to July. This is caused by an increase of mastitis in dairy farming. At healthy dairy cows the lactose amount is stable in the terms of milk composition and it moves on the level of 4.5 5%. 276 P age

5 Figure4 Biplot display of variables and observations for analyzed parametres To build a biplot for the farm analysis values scaling was used to suppress the high scattering of the first two variables, because scaled variables have dispersion equal to 1. Since the centering was carried out, they are based in point [0,0] (zero mean values of variables). Evaluation of biplot : the maximum amount of fat is present in months of Oct, Nov, Mar (October, November, March) the minimum amount of fat is present in July lactose is high in winter months, lower in summer months SCC and lactose are jsou negativly correlated variables urea, SCC and proteins are positively correlated variables. They have smaller values of variables generally in winter months, in summer months generally average and above average. The results on the farm and milk analyses through the monitored year proved negative correlation between SCC and lactose amount, which corresponds with results of more works (Renner 1972, Bergmann 1978, Hanuš and Suchánek 1991, Hanuš et al. 1995, 2009). In these studies the same negative correlation between somatic cells count and lactose amount was proved. This result can be led close to a possible mastitis in dairy cows and development of mastitis. The process of the disease causes increasing pathogenic activity which was proved in milk samples. This process reduces the secretory epithelium and formation of lactose in the mammary gland. It is therefore an intensification of immune reaction of the organism when increasing somatic cells count. Lactation stage can be also an agent of decreasing the amount of lactose and increasing somatic cells count along lactation progression, mainly towards its end (Hanuš et al 2010). CONCLUSION The aim was to determine the relation between the number of somatic cells and the amount of lactose at a dairy herd of cattle managing in an organic farming mode. Monitored were individual milk samples through a period of one year. Based on the results it can be stated that the relation between somatic cells count and the amount of lactose is in a mutual negative correlation. The results can be used in zootechnical practice not only when filtering the results of non-infectious mastitis, but also when analyzing in rutine monitoring systems, screening a herd or when managing a prevention of occurance of product disorders of dairy herd. 277 P age

6 REFERENCES Bergmann, J Laktosegehalt und Zellzahl in Einzeltierproben. Der Tierzüchter. ČESKOMORAVSKÁ SPOLEČNOST CHOVATELŮ A.S. 2016: Laboratoř pro rozbor mléka - Brno [online]. Available at: [ ]. ČSN :1999. Stanovení složení mléka infračerveným absorpčním analyzátorem. Praha. ČSN EN ISO :2007. Stanovení počtu somatických buněk. Praha. Hanuš, O., Hronek, M., Hyšpler, R., Yong, T., Tichá, A., Fikrová, P., Hanušová, K., Sojková, K., Hanuš, O., Suchánek, B Variabilita a obsah somatických buněk v mléce krav pod vlivem některých vnitřních a vnějších faktorů. Živočišná výroba r. 36. Hanuš, O., Ticháček, A., Kopecký, J., Příspěvek k práci s výsledky počtu somatických buněk v mléce jednotlivých krav. Mliekarstvo r. 26. Kopecký, J., Jedelská, R., Vztah mezi počtem somatických buněk a obsahem laktózy v mléce různých druhů savců. [online]. Available at: 7.pdf. [ ] Navrátilová, P. a kol Hygiena produkce mléka. VFU v Brně, ústav hygieny a technologie mléka. Renner, E Möglichkeit der Feststellung von Eutererkrankungen mit dem Infrarot-Milchanalysis (IRMA). Dtsch. Molk. Samková, E Mléko: produkce a kvalita: Milk: production and quality. 1. vyd. České Budějovice: Jihočeská univerzita v Českých Budějovicích. Semjan, Š Výroba kvalitného mlieka. Bratislava. Príroda, vydavatelstvo kníh a časopisou. Vorlová, L., Borkovcová, L., Králová, M., Kostrhounová, R. a kol Jakost a zdravotní nezávadnost syrového mléka, sborník semináře. Výsledky stanovení fyzikálně chemických parametrů bazénových vzorků mléka. Veterinární a farmaceutická univerzita Brno. 278 P age