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SHEEP MILK QUALITY AND PRODUCTION DURING LACTATION

Fenyvessy, József Jávor, András
University of Horticulture and Food Industry Debrecen University of
College of Food Industry Agriculture Sciences
Szeged, Hungary Debrecen, Hungary

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ABSTRACT

The authors investigated the fat, protein and lactose contents, protein composition, and somatic cell count of milk samples of six genotypes of sheep as well as their milk production during lactation. The genotype Merino, Langhe F1 and Pleven F1 gave the best values for the fat, protein and lactose contents, respectively. The somatic cell count fluctuated during the lactation months and distributed about 30 percent for classes I, II, and III. each, and about 10 percent for class IV. In the case of the milk production the Lacaune F1 and East-Friesian F1produced the highest amount of milk during the lactation which was about 30 percent more than Hungarian Merino.
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INTRODUCTION

The milking of the sheep has a considerable tradition in Hungary. Nevertheless very controversial tendencies can be established in the number of milked sheep and milk quantity in the past decades (Szakály, 1993; Fenyvessy, 1993).
The Hungarian Merino is a triple utilization breed of sheep and it has only an average or sometimes poor milk production compared to the specialized breeds. One can get from the combing Merino proved and well-fed, 40-50 litres of milk (Veress, 1990) and the most dams are able to produce 25-35 litres of milk (Kukovics, 1988).
The insufficient data in the literature were the grounds for extending our analysis to the investigations of the constituents of milk and production during lactation.

MATERIAL AND METHODS

The determination of the sheep milk composition by investigation of individual samples. The milk samples were obtained by regular sampling of six genotype - Langhe F1, Sarde F1, East-Friesian F1, Pleven F1, Lacaune F1 and Hungarian Merino sheep. The length of the lactation of the genotypes differed from each other, but the sampling was made every ten days. We compared the figures of the different genotypes to the Hungarian Merino and recorded the differences. We have determined the following parameters: fat, protein, protein fractions and milk production.
The compositional investigation was carried out with Milko Scan 104 equipment, while the somatic cell count investigation was carried out with Laborscale Analyser PSA1. The determination of the somatic cell count was based on 434 samples of collected ewe's milk.

RESULTS AND DISCUSSION

Fat content

During lactation, the average fat content was 6.83 percent, 6.75 percent, 6.62 percent, 6.76 percent, 6.52 percent and 6.94 percent for the genotypes Langhe F1, Sarde F1, East-Friesian F1, Pleven F1, Lacaune F1 and Hungarian Merino, respectively (Table 1 and Figure 1).
The fat content showed an increasing tendency in all genotypes during lactation. Despite the fact that the Lacaune produced the lowest fat content, its fat production was 96.0 percent higher than that of the Hungarian Merino. The East-Friesian F1 produced the highest amount of fat (5.76 kg) which was 167.4 percent higher than in the Hungarian Merino.

Table 1. Fat content of the ewe's milk according to the genotype

Genotypes

n

Average %

Error

Difference from Hungarian Merino [%]

Langhe F1

136

6.83

0.18

-1.7

Sarde F1

142

6.75

0.18

-2.8

East Friesian F1

97

6.62

0.29

-4.7

Pleven F1

170

6.76

0.15

-2.7

Lacaune F1

19

6.52

0.31

-6.4

Merino

119

6.94

0.40

0.0


Figure 1. Fat content of the ewe's milk according to the genotype

Protein content

During the lactation the average protein was 6.27 percent, 5.93 percent, 5.84 percent, 6.10 percent, 5.40 percent and 6.59 percent for the genotypes Langhe F1, Sarde F1, East-Friesian F1, Pleven F1, Lacaune F1 and Hungarian Merino respectively (Table 2 and Figure 2).
The Lacaune F1 produced the largest amount of protein, namely 5.3 kg which was 165.3 percent higher than the protein content of the Hungarian Merino. The protein production of the other genotypes in comparison to the Hungarian Merino were 4.31 kg (132.2 percent), 3.53 kg (108.3 percent), 5.12 kg (157.1 percent) and 3.61 kg (110.7 percent) for Langhe F1, Sarde F1, East-Friesian F1 and Pleven F1 respectively.
We experienced a slight variation in protein content - it showed an increasing tendency during lactation.

Table 2. Protein content of the ewe's milk of different genotypes

Genotypes

n

Average %

Error

Difference from Hungarian Merino [%]

Langhe F1

136

6.27

0.07

-4.9

Sarde F1

142

5.93

0.08

-10.0

East Friesian F1

97

5.84

0.12

-11.4

Pleven F1

170

6.10

0.06

-7.4

Lacaune F1

19

5.40

0.28

-22.0

Merino

119

6.59

0.16

0.0


Figure 2. Protein content of ewe's milk of different genotypes

Protein composition

The casein protein fraction had a ratio of 78.2 percent within the total protein content which is very important from the point of view of cheese production. The percentage amounts of the different genotypes were 4.9 percent, 4.63 percent, 4.56 percent, 4.76 percent, 4.22 percent and 5.05 percent for Langhe F1, Sarde F1, East-Friesian F1, Pleven F1, Lacaune F1 and Hungarian Merino, respectively (Table 3). We have to calculate the decrease of the casein fraction during the milk processing depending on the technical level of the applied technology (Figure 3).

Table 3. Protein composition of the ewe's milk of different genotypes

Genotypes

n

Average %

Error

Difference from

   

Casein

whey protein

 

Hungarian Merino [%]

Langhe F1

136

4.90

1.37

0.07

-5.1

Sarde F1

142

4.63

1.30

0.08

-11.1

East-Friesian F1

97

4.56

1.28

0.12

-11.3

Pleven F1

170

4.76

1.44

0.06

-8.2

Lacaune F1

19

4.22

1.18

0.23

-22.0

Merino

119

5.05

1.44

0.16

0.0


Figure 3. Casein content of the ewe's milk of different genotypes

Lactose content

Countary to the other constituents, the lactose content had the same ratio in the milk of different genotypes. The average values were 4.69 percent, 4.74 percent, 4.77 percent, 4.62 percent, 4.55 percent and 4.71 percent for Langhe F1, Sarde F1, East-Friesian F1, Pleven F1, Lacaune F1 and Hungarian Merino, respectively (Table 4 and Figure 4).
The highest lactose content can be found in the milk of the East-Friesian F1, which is 1.2 percent higher than the Hungarian Merino's value. The lowest amount occurred in the milk of the Lacaune F1, which is 3.5 percent lower than in the Hungarian Merino milk.

Table 4. Lactose content of the ewe's milk of different genotypes

Genotypes

n

Average %

Error

Difference from Hungarian Merino [%]

Langhe F1

136

4.69

0.06

-0.4

Sarde F1

142

4.74

0.06

+0.5

East Friesian F1

97

4.77

0.10

+1.2

Pleven F1

170

4.62

0.05

-2.0

Lacaune F1

19

4.55

0.18

-3.5

Merino

119

4.71

0.13

0.0


Figure 4. Lactose content of the ewe's milk of different genotypes

Somatic cell count

Six one-month periods, we examined the somatic cell count of collected Merino ewe's milk and studied the unfavourable effects of milk of high somatic cell count on the industrial processing, too. On the basis of examination of 434 samples we concluded that 25.6 percent and 57.1 percent of the samples had somatic cell counts lower than 500 000/cm3 and 1 000 000/cm3, respectively (Table 5).
Correlation was found between the increased somatic cell count of milk and both the increased loss of fat and the amount of milk used for the production of 1 kg of cheese.

Table 5. Somatic cell count of ewe's milk per month

Samples

Somatic cell count x 103 /cm3

Month

Number

<500

500-1000

1000-2000

>2000

II.

39

28.2

35.9

12.8

23.1

III.

58

20.7

32.8

24.1

22.4

IV.

96

39.6

24.0

22.9

13.5

V.

78

3.3

29.5

30.8

6.4

VI

125

16.0

37.6

33.6

12.8

VII

38

10.5

29.0

44.7

15.8

Total/av.:

434

25.6

31.5

28.6

14.3

Milk production

The length of the lactation period in the case of these six genotypes ranged between 85 and 111 days. The shortest was in case of Hungarian Merino and the longest was in the East-Friesian (Table 6). The amount of milk was the highest in the case of Lacaune F1 genotype (Table 7). Due to the high daily amount, it is more than two times higher than in the case of the Hungarian Merino (Table 8). During the lactation some of the parameters were different between morning and evening. Fat and somatic cell were constantly higher in the evening milking; on the contrary, production was higher in the morning milk. The other parameters do not present different trends in the two milkings.

Table 6. Length of the lactation period of investigated ewes according to the genotype (day)

Genotypes

n

Average [day]

Error

Difference from Hungarian Merino [%]

Langhe F1

136

99.13

4.03

16.6

Sarde F1

142

97.14

4.07

14.2

East Friesian F1

97

110.87

6.56

30.3

Pleven F1

170

92.88

3.41

9.2

Lacaune F1

19

107.30

11.90

26.2

Merino

119

85.04

9.13

0.0

Table 7. Milk production of the investigated ewes during the lactation according to the

Genotypes

n

Average [litres]

Error

Difference from Hungarian Merino [%]

Langhe F1

136

68.75

3.58

38.8

Sarde F1

142

59.47

3.61

20.1

East-Friesian F1

97

87.06

5.82

75.8

Pleven F1

170

59.14

3.03

19.4

Lacaune F1

19

99.80

12.41

101.6

Merino

119

49.51

8.09

0.0

Table 8. Daily milk production of the investigated ewes according to the genotype [litres]

Genotypes

n

Average [litres]

Error

Difference from Hungarian Merino [%]

Langhe F1

136

0.69

0.02

17.8

Sarde F1

142

0.61

0.02

4.2

East Friesian F1

97

0.75

0.04

28.9

Pleven F1

170

0.63

0.02

7.5

Lacaune F1

19

0.93

0.12

34.5

Merino

119

0.58

0.05

0.0

REFERENCES

Fenyvessy, J. 1993. Figures to the composition of the milk Hungarian Merino. In: Állattenyésztés és Takarmányozás. Supplement No. 1.
Jávor, A. - Sás, Gy. - Veress, I. & Kovács, Z. 1993. The effect of the feeding on sheep milk production. In: Állattenyésztés és Takarmányozás. Supplement No. 1.
Kukovics, S. 1988. A juhtej minségét befolyásoló beltartalmi értékek alakulása a mennyiség függvényében [Developing the quality influencing constituents in dependence on the quantity], In: Állattenyésztési és Takarmányozási Kutató Központ kiadványa 60-63 p.
Szakály, S. 1993. The possibility of milk processing on the Hungarian Dairy small ruminant farms. In: Állattenyésztés és Takarmányozás. Supplement No. 1.
Veress, L. 1990. Juhtartásunk jövjérl [On the keeping sheeps in the Future], In: Állattenyésztés és Takarmányozás 39. 2:103-109

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