Bulletin USAMV-CN, 63 - 64/2007

THE STUDY OF THE SOMATIC CELLS COUNTING (SCC) FROM SHEEP MILK OBTAINED IN CONVERSION AND ORGANIC CERTIFIED FARMS* Man C.*, Cristina Maerescu**, I. Ivan*** * U.S.A.M.V. Cluj-Napoca, e-mail: [email protected], ** Universitatea Oradea, ***Universitatea Tehnică Cluj-Napoca

Key words: somatic cells, conventional and organic sheep milk Abstract. The study concerning the total somatic cells counting (SCC) from the sheep milk collected from conventional and organic farms shows the following aspects: The milk from conventional farms with different milking sheep effectives (10-50 heads; 51-100; 101300; 301-500), contains between 98,000 and 5 millions SC/mL. The share of the samples with under 500,000 SC/mL (corresponding milk), was of 21.90%, bigger in small farms and smaller in big farms (31.20%, 12.60%, respectively). The share of the satisfactory milk samples (500,000 – 1,000,000 SC/mL) was 29.45% in average, and 29.83% for those which are on the limit of processing (1 – 2 millions SC/mL). The samples with over 2,000,000 SC/mL milk, of very low quality, recorded an average of 18.82%, and led to prejudices in its processing. The milk collected from farms in conversion or organic certified have a slight better technological quality (20-24% samples under 500,000 CS/mL and only 14-17% samples with over 2,000,000 CS/mL). This is not determined by the rearing system with a more serious technological flow.

INTRODUCTION

SCC from sheep milk is controlled by the health status of the animals, being correlated to its bacteriological quality (Ruiu and Pulina, 1992). The mammita is the most frequent disorder of the mammary gland which alters the milk qualitative traits and processing suitability, because increases the permeability of the mammary epithelium and allows the passage of some blood components in milk (Ranucci and Morgante, 1994; Harmon, 1995). The duration of the cell reaction of the infected udder depends on the duration of the infection which is influenced by the pathogen power of the biotic agent (infections with staphylococci are of long duration, and are followed by those produced by streptococci, and enterobacteria). The cell reaction identified by SCC/mL milk is the result of the interaction between many factors (Rota et al., 1993; Man C et al., 2003; Rotaru O. et al., 1998, 2006; Hicks et al., 1994; Zeng and Escobar, 1995; Bencini and Pulina, 1997; Pirisi, 2000), as: the pathogenic power of the infectious agent, the general resistance of the animal, the maintenance conditions, the milking hygiene, different stress factors (temperature, pressure on mammary gland), sheep age and lactation month. The increase of the milk SCC determine the decrease of the fat and casein content, and increase of the non proteic nitrogen in milk, and in special cases the milk does not coagulate being not suitable for processing (Duranti and Casoli, 1991; Pulina, 1991; Bufano et al, 1994). The somatic cells affect the mineral component of the milk, determining the increase of the phosphorus, potassium and magnesium levels meaning the constant increase of the pH (Harmon, 1995). These alterations determine lower coagulation parameters, as: velocity of *

Paper supported by CNCSIS

coagulum formation, its consistency and loose of high share of fat from whey (Duranti and Casoli, 1991; Pirisi et al., 1994). The Directive EEC 92/46/1992 of the European Union contains the admitted norms for SCC from cow milk, but withot refereces to sheepor goat milk. Within the International Symposium ”Somatic Cells of Small Ruminantus”, Italy 2003, there were made suggestions to the authorities f the European Commission concerning the sheep and goat milk. It must contain less than 1,500,000 SC/mL (Barbarosa et al., cited by Rotaru O, 2006). In USA, the norm is of 750,000 SC/mL, but the farmers cannot respect it (Droke et al., 1993). MATERIAL AND METHOD

In Romania, systematic examinations concerning the technological (SCC) and bacteriological (TGN) quality of sheep milk are not performed, and the producer is not paid according to milk quality, taking into account that 80-90% sheep milk is processed in farms according to traditional techniques. The characterization of the sheep milk concerning the SCC and identification of some influence factors is the aim of this paper. 95 samples from 4 farm categories (with 10-15 sheep; with 50-100 sheep; with 100-300 sheep and with 300-500 sheep) were analyzed in the first phase. The samples were harvested in different lactation phases, but only milk samples collected by flock (farm) were examined in the end of the milking. Al farms practice the conventional production system. During the second phase, milk samples from farms in Ist and IInd year of conversion (6 farms) and organic certified (2 farms) were comparatively examined, in order to compare the results with those obtained from conventional farms. The milking was manually performed in all farms. The automatic counting method was used. The Fossomatic System (fig. 1) was used and device was calibrated for sheep milk.

Fig 1. Fossomatic device for determination of SCC from milk

RESULTS AND DISCUSSIONS

The experimental conditions and results obtained in determination of SCC/mL milk in conventional farms are presented in table 1 and fig. 2.

Table 1 The evolution of SCC/mL milk in conventional farms Percent repartition of the SCC/mL milk samples Under 500,000 – 1,000,000 – Over 500,000 1,000,000 2,000,000 2,000,000 31.20 36.40 18.20 14.20 25.60 33.10 22.90 18.40 18.20 28.60 33.60 19.60 12.60 19.70 44.60 23.10 21.90 29.45 29.83 18.82

No. of farms 4 4 2 2 12

under 500,000

1 - 2 mil.

18,4 19,6 23,1

22,9

33,6

500,000-1 mil.

18,2

19,7 12,6

18,2

33,1 28,6

31,2

25,6

45 40 35 30 25 20 15 10 5 0

36,4

%

14,2

Farm 10-50 heads Farm 51-100 heads Farm 101-300 heads Farm 301-500 heads TOTAL/AVERAGE

No. of examined samples 43 32 12 8 95

44,6

No. of milked sheep by farm

5-10 heads 51-100 heads 101-300 heads 301-500 heads

over 2 mil.

Fig.2. evolution of SCC/mL milk in conventional farms

The experimental conditions and results by milk samples harvested from farms in conversion and organic certified are presented in table 2 and fig. 3. Table 2 The evolution of SCC/mL milk in farms in conversion and organic certified No. of milked sheep by farm In conversion Organic certified*

No. of examined samples 6 2

No. of farms 24 12

Percent repartition of the SCC/mL milk samples Under 500,000 – 1,000,000 – Over 500,000 1,000,000 2,000,000 2,000,000 24,60 38,00 20,00 17,40 20,20 49,60 16,00 14,20

* one farm has 3,500 milking shep and the other 126 milking sheep

49,6

% 38

50

24,6 20,2

40

conversion 16

20

17,4 14,2

20

30

organic certified

10 0 under 500,000 500,000-1 mil.

1 - 2 mil.

over 2 millions

Fig.3. The evolution of SCC/mL milk in farms in conversion and organic certified

Because in Romania systematic studies concerning the SCC/mL sheep milk were not performed, the results of our research represents priority for the Romanian bibliography and can be considered the reference point for the estimation of the data which will be obtained, and for the implementation of some measures of improvement of the hygienic and technological quality of the milk obtained in sheep farms. Our results are reference point in Eastern Europe for the sheep farms in conversion and organic certified. In analyzing these date we started from few bibliographical citations concerning the worldwide situation of sheep milk. According to the International Center of Resources and Valuation of Information by small ruminants milk chain (CIRVAL, 2001, 2002, 2004), the average value of SCC/mL milk by 129,896 sheep milk analyzed samples was of 1,707,000, decreasing from the year 2000 to 2004 (data for Sardinia – Corsica). In Hungary, Fenyvessy I. and Javor A. (1993), obtained by 434 analyzed sheep milk samples 25.6% samples under 500,000 SC/mL; 31.5% samples between 500,000 – 1,000,000 SC/mL; 28.6% between 1 and 2 millions and 14.3% samples had over 2 millions SC/mL milk. The highest share of SC/mL milk was recorded in milk samples harvested in last 2 months of lactation. Relatively similar data were obtained by Legarra A. and Mendizabal F.J. (1998) when they examined 43,536 sheep milk samples, harvested from Basc region and Navarre. In Mediterranean Europe, with tradition in sheep and goat rearing, the aimed threshold concerning the SCC/mL ship milk, decreased from 1.5 – 3 millions in 1999, to 1 – 2 millions /mL in 2003. Concerning the EU Directive 46/923, according to SERVIZIO and SVILUPPO REGIONALE, the repartition of the results, expressed in percents, by classes of somatic cells, in milk and mixed sheep breeds manually and mechanically milked is presented in table 3. Table 3 The repartition of results (%) by somatic cell classes and specialized sheep breeds Issue

Under 500,000 500,000 – 1,000,000 1,000,000 – 2,000,000 Over 2,000,000

Milk sheep breeds Manually milked Mechanically milked 34 41 17 8

23 19 31 27

Mixed sheep breeds Manually milked Mechanically milked 45 50 28 25 18 25 9 0

The results obtained in our trail concerning the mixed sheep breeds manually milked presented in table 3 are similar with those obtained in different Romanian sheep farms. Mary Jarvis (1994), estimates that 250,000 SC/mL milk, represents desiderate to achieve, but under 750,000/mL, can be accepted. Jeromy Ten Hag suggests the maximum threshold of 1.6 millions SC/mL sheep milk. The British Sheep Dairying Association requires less than 400,000 SC/mL milk for sour milk and rough milk destined to obtaining milk products thermically not treated. The payment methods used for sheep milk in countries where quality examination is performed also are interesting. In Italy, according to the EU Directive UE 46/923, the basic price is paid for milk with 1.3 – 1.8 millions SC/mL, and the bonus begin from 1 million SC/mL and is maximum for a content under 500,000 SC/mL. The penalties are applied from over 1.8 millions SC/mL and are maximum at 3 millions SC/mL. But this payment rule is not uniform by entire country. In most countries of the world the sheep milk is not paid according to the quality and only in few countries qualitative examinations are performed by producers. Within concrete conditions from the studied farms, only 22% of analyzed samples had less than 500,000 SC/mL, meaning they accomplish the requirements for the first quality milk. 30% are with 500,000 – 1,000,000 SC/mL, meaning generally satisfactory milk. 30% of samples had 1 – 2 millions SC/mL and 18% more than 2 millions SC/mL, being not correspondent. Values of 5 millions SC/mL, associated to high TGN were often recorded in collected milk, which reveals the precarious sanitary status of the mammary gland in many ewes from the flock. In large milked sheep flocks, of over 300 heads, the share of the samples with less than 500,000 SC/mL is lower compared to small farms and share of the samples with more than 1 million SC/mL increased. Concerning the milk from organic certified farms, or in conversion, the evolution of the SCC is similar with the conventional milk, even the share of the samples with less than 1,000,000 somatic cells/mL, is higher compared to the values obtained in conventional farms. CONCLUSIONS

The following aspects concerning the number of somatic cells/mL by milk were revealed after the analyze of 95 collected sheep milk samples from farms with variable sheep number by flock (10-50 heads, 51-100 heads, 101-300 heads and 301-500 heads): 1. The share of the samples with less than 500,000 CS/mL, meaning not correspondent, was 21.90% in average; the highest percent of samples belonging to this category was recorded in farms with 10-15 milked ewes and the lowest (12.6 – 18.2%) in flocks with more than 300 milked ewes. 2. The share with satisfactory milk samples with 500,000 – 1,000,000 SC/mL, was 29.45% in average, decreased to 36.4% in flocks with less than 50 milked ewes to 19.7% in flocks with more than 300 milked ewes. 3. The share of the samples with 1 – 2 millions SC/mL, meaning milk which is situated at the limit of use for cheese producing is high, of 29.83%, and variability within farms was high, from 18.2% in small farms, to 44.6% in farms with more than 300 milked ewes. 4. The milk with over 2 millions SC/mL (2-8 millions), has an average share of 18.82% from total samples, with variations between 14.2% in small farms and 19.6-23.1% in big farms. 5. The organic certified milk and the milk obtained from farms in conversion recorded a higher share of samples with less than 1,000,000 SC/mL, compared to conventional milk, with not big differences, generally.

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