88 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [ I, II

                                                                                          TABLE

                                    Variation of lactation yield with age

                                                                                          Lactation

Total lactation yields in lbs

1

2

2

3

3

4

4

Below 499 ....

2

..

..

2

1

..

..

500—749.....

5

..

..

1

..

2

. 1

750—999.....

..

..

..

..

..

..

..

1000—1249 ....

7

3

2

1

1

3

3

1250—1499 ....

7

8

8

1

1

2

1

1500—1749 ....

3

6

4

5

4

3

1

1750—1999

16

9

9

6

..

6

6

2000—2249 ....

16

12

8

15

12

7

1

2250—2499 ....

8

16

14

11

8

5

3

2500—2749 ....

24

17

13

14

12

12

9

2750—2999 ....

20

21

17

19

13

11

6

3000—3249 ....

28

15

9

17

14

15

10

3250—3499 ....

19

24

21

18

16

12

8

3500—3749 ....

28

26

23

21

14

15

10

3750—3999 ....

26

21

18

17

14

14

11

4000—4249 ....

23

18

16

13

9

11

10

4250—4499 .

11

27

24

19

19

10

9

4500—4749 ....

13

18

16

8

7

12

8

4750—4999 ....

11

11

10

21

19

16

10

5000—5249 ....

15

9

9

11

9

8

6

6250—5499 .

6

12

8

8

6

7

4

5500—5749 ....

6

8

7

6

6

12

9

5750—5999 ....

6

7

7

9

8

6

2

6000—6249 .

4

7

7

4

4

3

3

6250—6499 .

1

3

3

2

2

4

2

6450—6749 .

1

2

2

5

2

4

3

6750—6999 .

1

3

2

3

2

3

2

7000—7249 .

2

1

1

2

3

1

1

7250—7499 .

..

1

1

..

..

..

..

7500—7749 .

..

2

1

1

1

3

1

7750—7999 .

1

1

1

..

..

1

8000—8249 .

..

..

..

2

2

..

..

8250—8499 ....

..

1

1

..

..

1

1

8500—8749 .

..

..

..

..

..

..

..

8750—8999 .

..

1

1

..

..

..

..

9000—9249 .

..

..

..

1

..

..

..

No. of cows .

310

..

263

..

209

..

..

Means .

3500

3838

3884

3912

4016

4069

4075

P. E. of means .

╤51

╤52

╤59

╤58

╤64

╤69

╤80

Differences between means

+338

╤73

+28

╤83

—53

╤94

—154

Comparative yield

100.0

108.8

108.8

109.58

109.58

111.09

111.09