SHEEP MILK QUALITY AND PRODUCTION DURING
LACTATION
Fenyvessy, József
Jávor, András
University of Horticulture and Food Industry
College of Food Industry
Szeged, Hungary
Debrecen University of
Agriculture Sciences
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.
231
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
Langhe F1
Sarde F1
East Friesian F1
Pleven F1
Lacaune F1
Merino
136
142
97
170
19
119
6.83
6.75
6.62
6.76
6.52
6.94
0.18
0.18
0.29
0.15
0.31
0.40
Difference from Hungarian
Merino [%]
-1.7
-2.8
-4.7
-2.7
-6.4
0.0
7
6.9
Fat content %
6.8
6.7
6.6
6.5
6.4
6.3
6.2
6.1
Langhe
F1
Sarde
F1
E.Friesian
F1
Pleven
F1
Lacaune
F1
Merino
Genotype
Figure 1. Fat content of the ewe’s milk according to the genotype
232
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
Langhe F1
Sarde F1
East Friesian F1
Pleven F1
Lacaune F1
Merino
n
Average %
Error
136
142
97
170
19
119
6.27
5.93
5.84
6.10
5.40
6.59
0.07
0.08
0.12
0.06
0.28
0.16
Difference from Hungarian
Merino [%]
-4.9
-10.0
-11.4
-7.4
-22.0
0.0
Protein content (average) %
7
6,5
6
5,5
5
4,5
4
Langhe F1
Sarde F1
East-Friesian
F1
Pleven F1
Lacaune F1
Merino
Genotypes
Figure 2. Protein content of ewe’s milk of different genotypes
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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 %
Casein
Error
whey protein
Difference from
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
Pleven F1
Lacaune F1
Merino
97
4.56
1.28
0.12
-11.3
170
4.76
1.44
0.06
-8.2
19
4.22
1.18
0.23
-22.0
119
5.05
1.44
0.16
0.0
Casein content (average) %
5,5
5
4,5
4
3,5
3
Langhe F1
Sarde F1
East
Friesian F1
Pleven F1
Lacaune F1
Merino
Genotypes
Figure 3. Casein content of the ewe’s milk of different genotypes
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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
Langhe F1
Sarde F1
East Friesian F1
Pleven F1
Lacaune F1
Merino
4.8
Average %
Error
Difference from Hungarian
Merino [%]
136
4.69
0.06
-0.4
142
4.74
0.06
+0.5
97
4.77
0.10
+1.2
170
4.62
0.05
-2.0
19
4.55
0.18
-3.5
119
4.71
0.13
0.0
Lactose content (average) %
4.75
4.7
4.65
4.6
4.55
4.5
4.45
4.4
Langhe
F1
Sarde F1
East Friesian
F1
Pleven
F1
Lacaune
F1
Merino
Genotypes
Figure 4. Lactose content of the ewe’s milk of different genotypes
235
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
Somatic cell count x 103 /cm3
Samples
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 EastFriesian (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
Langhe F1
136
99.13
4.03
16.6
Sarde F1
142
97.14
4.07
14.2
97
110.87
6.56
30.3
East Friesian F1
Pleven F1
Lacaune F1
Merino
236
Average [day]
Error
Difference from Hungarian
Merino [%]
170
92.88
3.41
9.2
19
107.30
11.90
26.2
119
85.04
9.13
0.0
Table 7. Milk production of the investigated ewes during the lactation according to the
genotype [litres]
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
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production. In: Állattenyésztés és Takarmányozás. Supplement No. 1.
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