Сельскохозяйственная биология, 2010, № 2, с. 54-58.

УДК 636.2.034:636.082:636.018

HERDLIFE AS DETERMINANT FOR COMPLEX EVALUATION OF THE BULLS

Zh.G. Loginov, N.R. Rakhmatulina, B.A. Servakh, N.V. Nebasova

The method of complex evaluation of the bulls by the means of polyfactorial indices of breading worth was proposed for selection of cows-daughters on productivity, exterior, udder quality and extremities strength, and also on the duration of practical use in dairy herds. By the example of the holsteinized Black-and-White fresh cows keeping on pedigree farms in Leningrad oblast’ the authors have compared the efficiency of tandem-type (sequential) selection with the efficiency of selection on polyfactorial indices.

Key words: selection, linear estimation, exterior, dairy production, productive life.

 

In many countries with developed dairy cattle breeding , the period of practical use of animals in a herd is 4,0-4,5 lactations, and this is the subject of  index selection as well as productivity and exterior qualities (1, 2). In Russia, in farms with high dairy production rates, the duration of practical use of cows does not exceed 2,5-3,0 lactations (3).
Most of economically important qualities are the result of complex physiological functions provided by heredity and environmental conditions. Being a part of population, an animal has its own indices of viability, fertility and exterior. We assume that duration of practical use of cows (DPU) is also the hereditary feature.
The subject of our work – building a model of polyfactorial indices of breeding worth of bulls-sires, to be used in selection of cows-daughters on milk productivity, udder quality, strength of extremities and duration of practical use in dairy herd.
Methods. The object of the study were 1,956 golstinized Black-and-White fresh cows, retired from herds for various reasons. The study was carried out upon the data obtained from pedigree farms of the Leningrad region (excluding animals, retired for " sale for breeding purposes" and "sale for private persons "): "Agro-Balt"(162 cows), "Grazhdanskij" (513), "Detskoselskij" (582), "Leninskij put"(127), "Pervomaiskoye" (7), "Petrovskij" (71), " Rabititsy" (379), "Razdol'je  (67), "Rastcvet " (21), " Rapti " (27) during the period 1996 - 2006.
The exterior of all studied animals was evaluated by the linear system (4). Data on milk production were stored in "2-mole" cards in computer database "SELEX", which is used in farms of the Leningrad region. Genetic and breeding parameters of productivity and exterior features were determined by conventional methods of variation  statistics (5), integrated exterior indices of udder condition (UDC) and firmness of legs (FLC) - by the method of American breeders (6, 7). The duration of practical use was calculated in years from the date of first calving to disposal of cows from herd. Coefficient of heritability of DPU was calculated by the formula:

 


where h2 - coefficient of heritability of parameter, Cx - factorial variance, Cy - total dispersion of parameter (5).
Polyfactorial indices of breeding worth of bulls-sires were composed according the methodological recommendations of RAAS and the RAA SRI of Genetics and Breeding of farm animals (7) by the following models:
PI8 = [2STAf 2STAp + + (0,5 STAe + 0,33 STAUDC + 0,17 STAFLC) + STADPU] x 100;
PI9 = [2STAf + STAp + 2 (0,5 STAe + 0,33 STAUDC + 0,17 STAFLC) + STADPU] x 100,
where PI8 and PI9 - polyfactorial indices of breeding worth of bull-sires, STAf, STAp, STAe, STAUDC, STAFLC and STADPU - standard transmissive ability of an animal in production of fat (F), protein (P), exterior (E), udder condition (UDC), firmness of legs (FLC), duration of practical use (DPU).
Authors tested the efficiency of tandem-type (sequential) selection of bulls on one of the parameters - breeding worth in milk production, production of fat per 305 days of lactation, protein yield, exterior, or duration of practical use of cows-daughters, as well as efficiency of selection by  polyfactorial indices PI7 (7), PI8 and PI9. PI7 doesn’t include DPU.
The entire population of studied cows were the daughters of 167 bulls-sires. The data analysis was performed upon  the bulls-sires who produced at least 15 daughters (n = 38).
Results. The average duration of using animal in herds did not exceed 2,13 years (779 ± 9 days). The largest number of cows (33,0%) retired due to gynecological diseases, troublesome calving and their aftertroubles,  diseases of udder (11,4%) and extremities (10,4%) (Table 1).

1. The number of cows retired from herds for various reasons, and duration of their economic use (pedigree farms of the Leningrad region, 1996-2006)

Reason of retirement

Retired

Duration of practical use,
M±m

heads

%

years

days

Troublesome calving and aftertroubles,  gynecological diseases

646

33,0

2,03±0,04

741±16

Udder diseases

223

11,4

2,04±0,07

745±24

Diseases of extremities

204

10,4

2,34±0,08

853±29

Low productivity

48

2,5

1,85±0,15

676±53

Other internal non-contagious diseases

350

17,9

1,91±0,05

696±17

Infectious and parasitic diseases

112

5,7

2,62±0,14

958±52

Fattening slaughter

141

7,2

1,82±0,08

666±28

Other reason

232

11,9

2,68±0,09

978±33

Total

1956

100

2,13±0,03

779±9

The milk yield in studied cows averaged 7692,0 ± 38,8 kg (fat content - 3,68%, protein content - 3,06%) (Table 2). Phenotypic and genetic variability of milk yield was high – 1717,0 and 859,6 kg, respectively. Production of fat per 305 days of lactation varied from 100,2 to 483,0 kg with a variation coefficient of 22.30%. The variation coefficient of milk protein production was 22.20%.

2. Selection and genetic parameters of productivity in cows retired in the 1st lactation (n = 1956, pedigree farms of the Leningrad region, 1996-2006)

Parameter

M±m

σф

h2

σg

Cv, %

Milk yield for 305 days of lactation, kg

7692,0±38,8

1717,0±27,4

0,25

859,6±13,7

22,30±0,36

Fat content, %

3,68±0,01

0,240±0,004

0,45

0,160±0,003

6,60±0,11

Protein content, %

3,060±0,003

0,140±0,002

0,45

0,090±0,001

4,60±0,07

Milk fat production, kg

282,60±1,42

63,00±1,01

0,35

37,30±0,60

22,30±0,36

Milk protein production, kg

235,30±1,18

52,30±0,84

0,35

31,00±0,50

22,20±0,36

The final grade of exterior

79,60±0,07

2,92±0,05

0,29

1,57±0,03

3,67±0,06

DPU, years

2,13±0,03

1,13±0,02

0,19

0,49±0,01

53,00±0,85

Note: σф — phenotypic variability of parameter, h2 — coefficient of heritability, σg — genetic variability of parameter, Cv — variation coefficient.

DPU heritability was 0,19 (19%), with variation coefficient of 53,00%. The final exterior grade by  the 100-point scale (4) averaged 79,60 ± 0,07 points, variation coefficient - 3,67%.
In population of retired cows, the value of  UDC (+) variants averaged +0,71 ± 0,02, and of (-) variants - 0,95 ± 0,03.  For FLC these averages were +1,31±0,03 and -1,70±0,05, respectively. The absolute values of  UDC varied from +2,63 to -7,74, FLC – from +5,97 to -10,61.
In 25% the best bulls-sires selected by one of the parameters, the cows-daughters demonstrated higher milk yield, production of fat and protein per 305 days of lactation - higher than in all other cows by 1,256 kg (P < 0,001),  44 kg (Р < 0,001) and 40 kg (Р < 0,001), respectively. (Table 3). However, these cows had the worse estimations of exterior, less quality of udder and extremities, and therefore, the shorter duration of practical use in herds. It’s futile to select bulls-sires only on DPU of their daughters: these cows had the higher DPU (by 0,69 years, or ~252 days), but the less production of milk, milk fat and protein per 305 days of lactation, compared to cows-daughters of other bulls -  by 1666 (Р < 0,001), 55 (Р < 0,001) and 51 kg (Р < 0,001, 0,001, <0,001) less, respectively.
In 20% the best bulls-sires selected by PI7, PI8 and PI9 , their cows-daughters had the higher UDC, FLC and E indices. In the bulls-sires estimated by PI8 and PI9 indices, the cows-daughters had the significant advantage in duration of practical use in herds, while having no worse production of milk, milk fat and protein than cows-daughters of other bulls (see Table. 3).
Thus, the complex evaluation of bulls-sires by the polyfactorial indices is more efficient than tandem-type selection. It helps to support the optimal level of selection differential on parameters of productive quality, exterior, quality of udder and extremities, and also on the duration of practical use in herds of cows-daughters.

3. The results of evaluation and selection of bulls-sires on one of parameters of cows-daughters (tandem-type selection) and by polyfactorial indices

Parame-
ters

Bulls-sires, %
(n = 38)

Num-
ber of cows-da-
ugh-
ters, heads

Milk
yeald per 305 days of lacta-
tion, kg

Production,
kg

 UDC

FLC

DPU,
years

Exte-
rior, grade

Polyfacto-
rial indices

milk
fat

milk pro-
tein

PI8

PI9

Tandem-type selection of  25 %  best bulls-sires

DPU,
years

25

195

6490±
499

244±
17

197±
14

-0,26±
0,30

-0,33±
0,10

2,72±
0,10

78,5±
0,3

50±
80

34±
70

75

1064

8156±
119

299±
4

248±
4

-0,14±
0,10

-0,05±
0,10

2,03±
0,10

79,7±
0,2

-78±
34

-81±
29

difference

-1666
**

-55
**

-51
**

–0,12

-0,28*

+0,69
***

-1,2
**

+128

+115

Milk
yield

25

306

8720±
43

320±
2

268±
1

-0,01±
0,10

-0,26±
0,20

1,99±
0,10

80,0±
0,2

70±
34

33±
40

75

953

7464±
215

276±
7

228±
7

-0,15±
0,10

-0,13±
0,10

2,25±
0,10

79,2±
0,2

-84±
39

-81±
34

difference

+1256
***

+44
***

+40
***

+0,14

–0,13

-0,26*

+0,8*

+154
**

+114*

BW in
milk
yield

25

285

8157±
282

300±
10

249±
9

-0,19±
0,20

-0,32±
0,30

2,14±
0,20

78,9±
0,4

121±
45

47±
50

75

974

7639±
224

282±8

234±
7

-0,10±
0,10

-0,11±
0,10

2,21±
0,10

79,6±
0,2

-100±
36

-85±
32

difference

+518

+18

+15

–0,09

–0,21

-0,07

-0,7

+221
***

+132
*

BW in
milk fat produc-
tion

25

263

8103±
270

301±
10

247±
9

-0,16±
0,20

-0,28±
0,30

2,28±
0,10

78,9±
0,4

161±
41

91±49

75

996

7656±
227

282±
8

235±
7

-0,10±
0,10

-0,12±
0,10

2,16±
0,10

79,6±
0,2

-113±
33

-99±
30

difference

+447

+19

+12

–0,06

–0,16

0,12

-0,7

+274
***

+190
**

BW in milk protein produc-
tion

25

280

8295±
247

307±
9

254±
8

-0,12±
0,20

-0,26±
0,20

2,15±
0,20

79,3±
0,4

158±
42

96±
49

75

979

7596±
224

280±
8

232±
7

-0,12±
0,10

-0,13±
0,10

2,20±
0,10

79,5±
0,2

-112±
33

-100±
29

difference

+699*

+27*

+22*

0,00

-0,13

-0,05

-0,2

+270
***

+196
**

Selection of 20 % best bulls-sires by polyfactorial indices of breeding worth

Polyfac-
torial index PI7

20

255

7933±
422

294±
15

244±
13

0,14±
0,10

0,25±
0,30

2,34±
0,10

79,8±
0,4

195±
32

182±
28

80

1004

7716±
209

284±
7

236±
6

-0,18±
0,10

-0,27±
0,10

2,15±
0,10

79,4±
0,2

-112±
31

-117±
24

difference

+217

+10

+8

+0,32**

+0,52*

+0,19

+0,4

+307
***

+299
***

Polyfac-
torial
index PI9

20

211

7898±
413

295±
15

242±
13

0,00±
0,20

0,08±
0,30

2,45±
0,20

79,5±
0,4

221±
28

187±
26

80

1048

7725±
211

284±
7

236±
7

-0,15±
0,10

-0,23±
0,10

2,12±
0,10

79,4±
0,2

-120±
29

-118±
24

difference

+173

+11

+6

+0,15

+0,31

+0,33*

+0,1

+34
1***

+305
***

Note: DPU – duration of practical use, BW – breeding worth, UDC – index of condition of udder, FLC – index of firmness of legs
*, ** and *** Р < 0,05; Р < 0,01 and Р < 0,001, resp.

 

REFERENCES

1. Van Raden  Р.М., Selection of Dairy Cattle for Lifetime Profit, in Proc. 7th World Congr. Genet. Appl. Livestock Prod., Montpellier, 2002, vol. 29, pp. 127-130.
2. Dankvert S.A. and Dunin I.M, Proizvodstvo i mirovoj rynok moloka v nachale XXI veka (Production of Milk and the Dairy Market in Early XXI Century), Moscow, 2002, pp. 24-27.
3. Loginov Zh.G., Rakhmatulina N.R. and Bragynets S.A., The Duration of Practical Use of the Holsteinized Black-and-White Cows with Various Milk Productivity, in Mat. Mezhd. nauch. conf. “Sovremennyje metody genetiki i selectsii v zhivotnovodstve” (Papers of Int. Sci. Congress “The Current Methods of Genetics and Selection in Animal Husbandry), Sanct-Petersburg, 2007, pp. 55-59.
4. Pravila otsenki teloslozheniya docherej bykov-proizvoditelej molochno-myasnykh porod (Rules of Evaluation the Physique of Cows-Daughters of Bulls-Sires of Dairy and Meat Breeds), Moscow, 1996.
5. Plokhinskii N.A., Biometriya (Biometry). Мoscow, 1970, pp. 62-66.
6. Sire Summaries, 2007, vol. 2, pp. 5-20.
7. Prokhorenko P.N., Loginov Zh.G., Rakhmatulina N.R. e.a., Kompleksnaya otsenka zhivotnykh v molochnom skotovodstve na osnove postroyeniya modelej polifaktornogo indeksa plemennoj tsennosti. Metodicheskiye rekomendatsii (Complex Evaluation of Animals in Dairy Cattle Breeding upon the Basis of Building the Models of Polyfactorial Index of Breeding Worth. Methodological guidelines.), Moscow, 2005.


Scientific Research Institute of Genetics and
Selection of Farm Animals, Russian Agricultural Academy,
Sankt-Petersburg 196625, Russia,
e-mail: paxmat@pochta.ru ,
b_serwakh@pochta.ru

Received May 14, 2008

 

 

 

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