145 Bulgarian Journal of Agricultural Science, 12 (2006), 145-152 National Centre for Agrarian Sciences
Milk Yield for Milking Period in the Sheep from the Newly Created Milk Breed in Bulgaria S. BOIKOVSKI1, G. STEFANOVA2 and N. STANCHEVA 1 Agricultural Institute, BG-9700 Shumen, Bulgaria 2 Agricultural Institute, BG-6000 Stara Zagora, Bulgaria
Abstract BOIKOVSKI, S., G. STEFANOVA and N. STANCHEVA, 2006. Milk yield for milking period in the sheep from the Newly created milk breed in Bulgaria. Bulg. J.Agric. Sci., 12: 145-152 It was established that the sheep from the Newly created milk breed in Bulgaria had high milk yield for a longer time, which is favorable for applying machine milking. The milk yield and the average daily milk yield of the sheep for the whole milking period were highest at IInd and more lactation and exceeded the sheep at Ist lactation by 4.71 and by 4.45%. The duration of the milking and the lactation period of the sheep at IInd and more lactation exceeded the sheep at Ist lactation by 8.15 and by 7.53% (P < 0.05). It was established that the analyzed heritability coefficients of some of the milk yield traits had low values and for the milking period at Ist lactation were approximately zeroed.
Key words: suckling, milking and lactation period, milk yield, heritability coefficient
Introduction Applying a hybridization system based on fine fleece, semi-fine fleece, creates the milk breed and partly specialized milk breeds and strains (Hinkovski at al., 1979, 1980, 1982 and 1984). Close schemes are used in the sheep from the selection, candidate-selection and a bigger part of the non-selection herds in Bulgaria (Tzvetanov, 1989; Dimov, 1995; Stancheva, 2002). The typical representatives of the Newly created milk breed significantly dif-
fer from the breeds taken participation in the hybridization and much more resemble the East Friesian breed (depending on the blood). Their udder is well developed with regular position of the teats which make them suitable for machine milking (Boikovski, 1993). They also have excellent adaptive abilities and are resistant to parasites, insects, ticks etc. and do not suffer from piroplazmoza (Hinkovski et al. 1984; Tzvetanov, 1989; Dimov, 1995). They are also characterized with an ability to keep their characteristic traits in a number of generations (Hinkovski et al.,
146 1984; Dimov, 1995). They can be changed quckly into desired direction. The objective of this study was to establish the milk yield for milking period in the sheep from Newly created milk bred in Bulgaria.
Material and Methods The whole complex of investigations in relation to the traits included into the milk yield was realized after the example of the herd from the Newly created milk bred, property of the Agricultural Institute, Shumen. The genetic structure of sheep was established on the basis of Pedigree Books. The degree of relationship was calculated for each individual animal by the method of Wright (1923) and depending on which level the common ancestors reoccurred five groups of relationship were formed: far – Fx =t o 0.39%, (the related animals are in the following levels – ІV-V, V-V, V-VІ etc.), moderate – Fx = from 0.78 to 1.56% (ІV-ІV, ІІІ-ІV etc.), close – Fx = 3.12 to 6.25% (ІІІ-ІІІ, ІІ-ІІІ etc.), mating between full siblings: Fx = 12.50% and more (ІІ-ІІ, І-ІІ etc.) and with unidentified relationship. On the basis of the mating type used the sheep were divided into three groups namely: originating from interline and interline mating and “with unidentified mating”. The following traits were investigated: milk yield and average daily milk yield for 120-day milking period, duration of milking during the suckling period, the milking and the lactation period. The traits investigated were controlled and registered by standard methods indicated in the Sheep Classification Instruction, performance control and breeding value estimation of sheep (2003). The milk yield was
S. Boikovski, G. Stefanova and N. Stancheva
established by separate controls and then was averaged for each animal. The characteristic of the traits was performed in accordance with the estimations from the multi-factor LS-analysis (Harvey, 1990). Some models including additional sources of variability like lactation number were used. The following linear model was used for the variance analysis of all traits studied: Yiji…..n = µ + Ai + Bj + Tn + eiji…..n Where: Yiji…..n - values of the traits used; µ - total average; Ai - effects of the factors chosen for the model with estimation of their levels; Bj Tn eiji…..n - random error of the model ≈ (0, δе 2). The variance estimations were calculated on the basis of the abovementioned model indicating the effect of the factors comprised by it and the F-criterion read the effect of each one of them. The estimations of the heritability coefficients (h 2) were calculated by the method of Sib-analysis by Becker (1968).
Results and Discussion During the first period i.e. for 120 days, 71.60% of the total amount of milk for milking period at Ist lactation was obtained, and at IInd and more lactations - 67.26% (Table 1). After the 120th day at Ist lactation averagely for 64.79 days 41.93 l milk was obtained with average daily milk yield 0.647 l and at IInd and more lactations -
147
Milk Yield for Milking Period in the Sheep from the Newly Created Milk Breed in Bulgaria
shows a longer maintenance of high milk yield during the period after the 120th day. The variation coefficients were in a normal range except the duration of the suckling period at Ist, IInd and more lactations (C = 59.923 and 42.269%). Of course, all this is a result from the high variation of
for 79.74 days - 50.59 l milk respectively. The average daily milk yield decreased in the sheep at Ist lactation from 0.881 l for 120 days to 0.647 l for the period after the 120th day and at IInd and more lactation from 0.866 l to 0.634 l or by 26.86 and 26.79%. This decrease is favorable and
Table 1 Total average of some traits of the milk yield in sheep from the Newly created milk N
Ist lactation
Traits
n
Milk obtained for 120 days, 1 Average daily milk yield for 120 days, 1 Milk obtained for milking period, 1 Average daily milk yield for milking period, 1 Suckling period, days
1. 2. 3. 4. 5.
x
S
C
IInd and more lactations E
n
x
S
C
E
105 105.67 26.07 24.671 2.408 162 103.940 24.05 23.142 1.818 105
0.881
0.22 24.670 2.408 162
0.866
0.20 23.141 1.818
105 147.58 41.51 28.125 2.745 162 154.530 32.74 21.185 1.664 105
0.799
0.23 27.635 2.697 162
105
38.33 20.29 59.923 5.165 162
0.774
0.18 23.236 1.826
40.190 16.99 42.269 3.321
6. Milking period, days
105 184.79 39.60 21.427 2.091 162 199.740 29.16 14.599 1.147
7. Lactation period, days
105 223.12 41.10 18.420 1.798 162 239.930 34.85 14.525 1.147
Table 2 F-criteria of significance at the variance analysis for the efect of some variance sourses on some of the milk yield
N
o
Sources of variantion
Milk yield for 120 days, 1
Average Duration Duration Duration Average Milk yield daily milk of the of the of the daily milk for yield for suckling milkking lactation yield for milking milking period, period, period, 120 days, 1 period, 1 period, 1 days days days n.s. n.s. n.s. n.s. n.s. n.s.
1 Sire' s line Dedree of 2 relationship
n.s. n.s.
n.s.
n.s.
n.s.
n.s.
n.s.
n.s.
3 Type of mating
n.s.
n.s.
n.s.
n.s.
n.s.
n.s.
n.s.
n.s.
n.s.
n.s.
n.s.
n.s.
+
+
+
+
n.s.
Close
+++
n.s.
+++
Close
Close
n.s.
n.s.
n.s.
n.s.
Close
Lactation number Purpose of the 5 lambs born 6 Dam' s line 4
Sources of variantion
n.s. n.s. n.s. n.s. n.s.
n.s.
n.s.
n.s.
n.s.
For 120 days
n.s.
Average daily milk yield for 120 days
n.s.
n.s.
n.s.
n.s.
n.s.
n.s.
n.s.
n.s.
Suckling period n.s.
+++
n.s.
n.s.
n.s.
n.s.
n.s.
n.s.
n.s.
n.s.
Milkking period n.s.
+++
n.s.
n.s.
n.s.
n.s.
++
n.s.
n.s.
Close
n.s.
++
n.s.
n.s.
Close
Average daily milk yield for 120 days
Milk yield
n.s.
Close
n.s.
Close
n.s.
Close
n.s.
Close
Suckling period
n.s.
+++
n.s.
n.s.
n.s.
n.s.
n.s.
n.s.
n.s.
+++
n.s.
+
IInd and more lactation Milk yield Duration of Average For daily milk milking yild for period milking period n.s. n.s. n.s. n.s. n.s. Milkking period
st
1. I 2. IInd and more
N
Lactation number
105 162
n
a 0.009 -0.009 t-test n.s.
Milk yield, 1
x 0.799 0.774
a SE 0.019 0.102 -0.019 0.102 t-test n.s.
Average daily milk yield, 1
For milking period SE x a SE 0.103 147.58 -1.125 18.672 0.103 154.53 1.125 18.672 t-test n.s.
Average daily milk yield, 1
x a SE x 105.67 1.129 12.427 0.881 103.94 -1.129 12.427 0.866 t-test n.s.
Milk yield, 1
For 120 days
Table 4 LS- estimations (a) of the effect of lactation number on the total amount of the average daily milk yield for 120 days and for the whole milking period
1 Sire' s line Dedree of 2 relationship Type of 3 mating Purpose of 4 the lambs born 5 Dam' s line
N Lactation period
Duration of For 120 days
Milk yield
Ista lactation Milk yield Average For daily milk milking yild for period milking period n.s. n.s. Lactation period
Table 3 F-criteria of significance at the variance analysis for the effect of some variation sourses on some of the milk yield traits by lactations
148 S. Boikovski, G. Stefanova and N. Stancheva
100.26
106.63
x
t-test 1-2+
-3.911
3.911
a 12.334
12.334
SE 0.835
0.889
x
t-test 1-2+
-0.033
0.033
a 0.103
0.103
SE
Average daily milk yield, 1
For 120 days Milk yield, 1
150.45
152.41
x
t-test n.s.
-1.281
1.281
a 18.534
18.534
SE 0.770
0.813
n
105 162
1. Ist 2. IInd and more
N
Lactation number 0.592 -0.592 t-test n.s.
a
SE 6.196 6.196
Suckling period, days 38.33 40.19
x
-6.067 6.067 t-test 1-2-+
a
SE 16.917 16.917
Milking period, days 184.790 199.740
x
x
a
17.345 17.345
SE
t-test 1-2 Close
-6.335 6.335 t-test 1-2-+
a
SE 0.101
-0.024 0.101
0.024
Lactation period, days 223.12 239.93
Duration of the periods of the milk yield
x
Average daily milk yield, 1
For milking period Milk yield, 1
LS-estimations (а) of the effect of the lactation number on the duration of the periods of the milk yield
Table 6
84
2. IInd and more
n
183
Purpose of lambs born
1. Ist
N
Table 5 LS- estimations (a) of the effect of the purpose of lambs born on the total and average daily milk yield for 120 days and for the whole milking period
Milk Yield for Milking Period in the Sheep from the Newly Created Milk Breed in Bulgaria
149
150 the trait (for Ist lactation - from 1 to 84 days and for IInd and more lactation - from 1 to 85 days). The high standard deviations of the traits studied are on principle characteristic for such studies in sheep and coincide with those reported by Dimov and Ivanova (2001) concerning the Splotchfaced Maritza sheep. This level of the phenotypic performance of milk yield in sheep for milking period was higher that the one established by other authors (Tzvetanov, 1989; Dimov, 1995; Petrova and Vitkov, 1996; Dimov and Ivanova, 2001; Stancheva, 2002) and put them in the group of sheep with average level of milk yield (Boikovski, 1995). The purpose of the lambs born (for slaughtering and for breeding purposes (P
