NationalLibraryOfScotland/medical-history-of-british-india huggingface dataset:
INVESTIGATIONS INTO THE FLUCTUATIONS OF MILK YIELD
WITH THE ADVANCEMENT OF LACTATION
BY
L. S. JOSEPH, G.B.V.C.,
Cattle Superintendent, Pusa,
AND
C. N. DAVE, B.AG. (BOM.),
Post-graduate Student in Animal Husbandry and Dairying,
Imperial Institute of Agricultural Research, Pusa.
(Received for publication on 22nd April 1931.)
(With three text figures.)
It is one of the most essential problems for a dairyman to maintain a regular and
steady supply of milk to his customers. The method usually adopted for this pur-
pose is to regulate the services and therefore the calvings of the animals throughout
the year. This alone does not completely and successfully solve the problem as it
is co-related with tendency to the decline of milk in different lactations. The
dairyman has, therefore, before regulating services, to analyse his stock with re-
spect to the monthly milk yield in each lactation ; thus to work out the general
tendency towards decline in milk with the advancement of lactation. By combin-
ing the knowledge of decline in milk yield with the regulation of services, he will be
able to overcome the difficulty with regard to the surplus or shortage of milk.
With a view to study the above problem, records of Montgomery breed of cows
at Pusa Cattle Farm were gone through. The investigation is sub-divided into two
headings:—
I. Effect of season on calving.
II. Decline in milk yield with the advancement of lactation.
EFFECT OF SEASON ON CALVING.
The number of cases studied in this connection works out at 1,553, being the
total number during the past 24 years, a detailed account of which is given in
Appendix A. The following Table gives a consolidated review of it.
( 200 )
FLUCTUATIONS OF MILK YIELD WITH ADVANCEMENT OF LACTATION 201
TABLE I.
Showing the season of calvings in Montgomery cows.
Months
No. of calvings
Percentage
Rank with respect to
calving.
January
160
10.3
II
February
141
9.1
III
March
138
8.9
IV
April
127
8.2
V
May
116
7.5
VII
June
111
7.2
VIII
July
109
7.0
IX
August
122
7.8
VI
September
111
7.2
VIII
October
109
7.0
IX
November
142
9.1
III
December
167
10.8
I
Total
1,553
It would appear from the above Table that the distribution of calvings is fairly
uniform throughout the year. The variations are from 7.0 to 10.8 per cent.
Fig. 1 gives a comparative view of the percentage of calvings in different months
of the year.
Fig. 1. Showing percentage distribution of calvings in Montgomery cows.
202
THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [ I, III
DECLINE IN MILK YIELD WITH ADVANCEMENT OF LACTATIONS.
The procedure adopted for this inquiry was to sort out the monthly milk yield
in each lactation along with the date of calving in each case. The latter was
essential in arriving at the exact number of days, the cow was in milk during the
first month of calving. It may be pointed out that it is the general practice at the
Pusa Farm to record the milk from the 7th day after calving, the days prior to that
being considered as the colostrum period. It is also the practice here to record the
lactation yield for ten calendar months, i.e., 304 days, which is the average lacta-
tion period in almost all the milch breed of cows. Hence the figures referred to in
this paper are in accordance with the above practice.
The total number of cases studied works up to 397 in all, a consolidated re-
view of the detailed analysis of which is given in Appendix B. The following Table
gives the monthly milk yield in different lactations.
FLUCTUATIONS OF MILK YIELD WITH ADVANCEMENT OF LACTATION
203
Showing the average monthly milk yield of Montgomery cows in different lactations.
Months
1
2
3
4
5
6
7
8
9
10
11
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
TOTAL
1st
lactation
Milk
yield
(lbs.)
No.
of
cases
183(13)*105
398
366
331
308
287
267
254
239
217
125
2,975
105
105
105
105
104
102
98
93
87
75
2nd
lactation
Milk
yield
(lbs.)
No.
of
cases
273 (15) 83
544
464
393
336
298
275
254
241
220
115
3,413
83
83
83
83
82
77
72
65
58
50
3rd
lactation
Milk
yield
(lbs.)
No.
of
cases
336 (16) 62
629
561
491
431
376
326
293
258
223
94
62
62
62
62
62
62
58
55
51
41
4,018
4th
lactation
Milk
yield
(lbs.)
No.
of
cases
342 (15) 57
667
597
522
453
411
358
301
265
229
130
57
57
57
57
56
56
56
51
45
36
4,275
5th
lactation
Milk
yield
(lbs.)
No.
of
cases
361 (16) 38
666
607
537
466
420
365
316
288
240
120
38
38
38
38
37
37
34
31
27
19
4,386
6th
lactation
Milk
yield
(lbs.)
No.
of
cases
290 (13) 25
596
526
452
416
388
325
286
265
207
100
25
25
25
25
24
24
23
22
20
15
3,851
7th
lactation
Milk
yield
(lbs.)
No.
of
cases
336 (16) 17
613
544
489
450
394
337
315
274
242
82
4,076
17
17
17
17
17
17
17
16
16
12
8th
lactation
Milk
yield
(lbs.)
No.
of
cases
340 (17) 10
587
531
454
431
384
338
308
303
218
242
10
10
10
10
10
10
10
9
9
4
4,136
* Figures in brackets show the number of days, for which the animals' first month's yield was recorded during the first month of calving.
204 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [ I, III
Inferences from Table II.
1. It would appear from the above table that irrespective of number of lacta-
tion, the milk yield tends to decline as the lactation advances, in spite of a number
of cases remaining constant up to six months.
2. That the milk yield shows a rapid rise from first to second and second to
third lactation by about 450 and 600 lbs. respectively, reaching its maximum in the
fifth lactation.
3. That there is a heavy decline in milk yield by about 500 lbs. from fifth to
sixth lactation.
Fig. 2 gives comparative view of lactation yields.
Fig. 2. Showing lactation yields of Montgomery cows.
FLUCTUATIONS OF MILK YIELD WITH ADVANCEMENT OF LACTATION
205
The following Table shows month to month decline in milk yield.
TABLE III.
Showing month to month decline in milk (lbs.) in different lactations of Montgomery
cows.
Decline from month
2nd to 3rd .
3rd to 4th
.
4th to 5th .
5th to 6th
....
6th to 7th .
7th to 8th .
8th to 9th .
9th to 10th
Total
.
Average
.
1st
lact.
32
35
23
21
20
13
15
22
181
22.6
2nd
lact.
80
71
57
38
23
21
13
21
324
40.5
3rd
lact.
68
70
60
55
50
33
35
35
406
50.7
4th
lact.
70
75
69
42
53
57
36
36
438
54.7
5th
lact.
59
70
71
46
55
49
28
48
426
53.2
6th
lact.
70
74
36
28
63
39
21
58
389
48.6
7th
lact.
69
55
39
56
57
22
41
32
371
46.4
8th
lact.
56
77
23
47
46
30
5
85
369
46.1
Total
504
527
378
333
367
264
194
337
2,904
Average
63.0
65.9
47.2
41.6
45.9
33.0
24.2
42.1
..
45.4
Inferences.
1. The above table shows that the average decline is greater up to seventh
month than in the remaining period of the lactation.
2. That the decline shows wide fluctuations in different lactations during the
same period.
3. That the average monthly decline shows a rapid rise from the first to the
third lactation reaching its maximum in the fourth after which it becomes less pro-
nounced.
4. That the average monthly decline of all lactation combined works out at
45.4 lbs. with 65.9 lbs. as maximum and 24.2 as minimum decline from third to
fourth and eighth to ninth month respectively.
It may be pointed out here that the above table of decline in milk includes
cases which showed some increase in their milk yield from one month to another.
Such cases showing increase in milk yield from second to third month in different
lactations formed 18 per cent. of the total number under observation. Among these
there were ten cases showing increase from third to fourth month and three, showing
increase from fourth to fifth month, as detailed below.
206
THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [ I, III
TABLE IV.
Showing increase in milk yield (lbs.) in different months of lactation.
Month
2nd to 3rd
3rd to 4th
4th to 5th
1st
lact.
30 (25)*
34 (5)
28 (3)
2nd
lact.
20(7)
..
..
3rd
lact.
44 (12)
54 (1)
..
4th
lact.
55 (12)
13 (2)
..
5th
lact.
55 (8)
19 (1)
..
6th
lact.
70 (2)
20 (1)
..
7th
lact.
14 (1)
..
..
8th
lact.
44 (3)
..
..
* Figures in brackets show number of cases in each lactation.
The following Table shows month to month percentage decline in milk in
different lactations:—
TABLE V.
Showing month to month percentage decline in milk in different lactations of Montgo-
mery cows.
Decline
from month
2nd to 3rd
.
3rd to 4th .
4th to 5th .
5th to 6th .
6th to 7th
.
7th to 8th
.
8th to 9th .
9th to 10th .
Average per cent.
decline with res-
pect to preceding
month.
1st
lact.
8.0
9.5
6.9
6.8
6.9
4.8
5.9
9.2
7.2
2nd
lact.
14.7
15.3
14.5
11.3
7.7
7.6
5.1
8.7
10.6
3rd
lact.
10.8
12.4
12.2
12.7
13.3
10.1
11.9
13.5
12.1
4th
lact.
10.5
12.5
13.2
9.2
12.9
15.9
11.9
13.5
12.4
5th
lact.
8.9
11.5
13.2
9.8
13.1
13.4
8.8
16.6
11.9
6th
lact.
11.7
14.0
7.9
6.7
16.2
12.0
7.3
21.8
12.2
7th
lact.
11.2
10.1
7.9
12.4
14.4
6.2
13.0
11.6
10.8
8th
lact.
9.5
14.5
5.0
10.9
11.9
8.8
1.6
28.0
11.3
Average 11.1 per cent.
Inference.
1. That on an average, the milk yield for each month is 11.1 per cent. less than
that of the preceding month.
FLUCTUATIONS OF MILK YIELD WITH ADVANCEMENT OF LACTATION
207
TABLE VI.
Showing the progressive percentage decline of milk in different lactations (based on 2nd
month).
Decline
from month
2nd to 3rd
.
2nd to 4th
2nd to 5th
.
2nd to 6th .
2nd to 7th
.
2nd to 8th
.
2nd to 9th
.
2nd to 10th .
Average
monthly
per cent. decline.
1st
lact.
8.0
16.8
22.6
27.9
32.9
36.2
40.0
45.3
5.7
2nd
lact.
14.7
27.7
38.2
45.2
49.4
53.3
55.7
59.6
7.4
3rd
lact.
10.8
21.9
31.4
40.1
48.0
53.2
58.8
64.4
8.0
4th
lact.
10.5
21.7
32.0
38.3
46.2
54.7
60.1
65.5
8.2
5th
lact.
8.9
19.4
30.1
37.0
45.3
52.7
56.9
64.1
8.0
6th
lact.
11.7
23.9
29.9
34.6
45.2
51.7
55.2
64.9
8.1
7th
lact.
11.2
20.2
26.5
35.6
44.9
48.5
55.2
60.4
7.5
8th
lact.
9.5
22.6
26.5
34.5
42.3
47.4
48.2
62.7
7.8
Average 7.6 percentage.
Inferences.
1. It would appear from the above table that the total percentage decline is
least in first lactation.
2. That from second to eighth lactation the average percentage decline remains
practically constant.
3. That on the whole the average percentage monthly decline in Montgomery
cows works out at 7.6.
208
THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [ I, III
Fig. 3 shows the average percentage monthly decline in different lactations of
Montgomery cows.
Fig. 3. Showing the average percentage monthly decline in milk in different lactations of Montgomery cows.
FLUCTUATIONS OF MILK YIELD WITH ADVANCEMENT OF LACTATION
209
APPENDIX A.
Showing the season of calvings in Montgomery breed (1907 to 1930).
Year
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
Total
Percentage
Rank with
respect
to cal¬
vings.
January
—
2
1
2
4
7
3
6
5
14
11
4
14
4
16
11
9
10
10
4
9
6
3
5
160
10.3
II
February
1
—
5
6
4
2
2
—
3
14
12
6
5
9
18
6
7
8
12
6
5
3
2
5
141
9.1
III
March
1
3
2
6
8
9
5
6
7
5
16
—
8
6
11
5
6
5
6
6
6
4
4
3
138
8.9
IV
April
2
5
2
8
8
2
6
4
-
5
11
—
3
7
8
6
7
4
8
7
8
5
4
7
127
8.2
V
May
1
—
3
6
2
1
5
—
4
6
8
2
7
9
4
6
1
8
3
7
15
4
10
4
116
7.5
VII
June
—
3
6
2
4
5
12
6
6
4
2
13
3
5
7
2
3
5
5
9
1
2
4
3
111
7.2
VIII
July
1
4
7
1
5
6
6
7
3
2
4
8
6
9
3
4
3
5
5
4
6
3
2
5
109
7.0
IX
August
1
1
4
1
9
1
4
4
7
7
4
11
3
6
18
7
3
4
3
3
9
6
2
4
122
7.8
VI
September
—
3
2
3
2
8
5
6
3
9
8
4
2
5
7
6
4
6
4
3
7
3
3
8
111
7.2
VIII
October
2
1
2
4
4
8
3
6
8
6
8
13
5
2
4
6
6
5
2
6
3
2
2
1
109
7.0
IX
November
2
6
1
1
5
5
5
10
2
5
14
3
10
11
12
11
3
9
9
5
5
2
4
2
142
9.1
III
December
1
2
4
7
9
3
10
6
6
13
5
8
6
11
4
10
13
9
6
7
6
7
5
9
167
10.8
I
Total
12
30
38
47
64
57
66
61
54
90
103
72
72
84
112
80
65
78
73
67
80
47
45
56
1,553
C
210
THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [ I, III
APPENDIX B.
Showing month to month lactation yields and their decline in Montgomery cows.
Months
1
2
3
4
5
6
7
8
9
10
11
Total
Average
monthly
decline
(lbs.)
Average
monthly
decline in
percent-
age.
1st Lactation
Milk yield in lbs.
183
398
366
331
308
287
267
254
239
217
125
2,975
...
Decline in lbs.
Month to month
decline per cent.
in 13 days.
32
35
23
21
20
13
15
22
...
...
181
...
8.0
9.5
6.9
6.8
6.9
4.8
5.9
9.2
...
...
...
22.6
Progressive decline
per cent.
8.0
16.8
22.6
27.9
32.9
36.2
40.0
45.3
...
...
..
...
5.7
No. of cases
105
105
105
105
105
104
102
98
93
87
75
...
...
2nd Lactation
Milk yield in lbs.
273
544
464
393
336
298
275
254
241
220
115
3,413
...
Decline in lbs.
Month
to month
decline per cent.
in 15 days
80
71
57
38
23
21
13
21
...
...
324
40.5
14.7
15.3
14.5
11.3
7.7
7.6
5.1
8.7
...
...
...
...
Progressive decline
per cent.
14.7
27.7
38.2
45.2
49.4
53.3
55.7
59.6
...
...
...
...
7.4
No. of cases
83
83
83
83
83
82
77
72
65
58
50
...
...
3rd Lactation
Milk yield in lbs.
336
629
561
491
431
376
326
293
258
223
94
4,018
..
Decline in lbs.
in 16
68
70
60
55
50
33
35
35
...
...
406
50.7
Month to
month
decline per cent.
days
10.8
12.4
12.2
12.7
13.3
10.1
11.9
13.5
...
...
...
...
Progressive
decline
per cent.
...
10.8
21.9
31.4
40.1
48.0
53.2
58.8
64.4
...
...
....
....
8.0
No. of casses
62
62
62
62
62
62
62
58
55
51
41
...
...
4th Lactation
Milk yield in lbs.
342
667
597
522
453
411
358
301
265
229
130
4,275
...
Decline in lbs.
in 15
70
75
69
42
53
57
36
36
...
...
438
Month to month
decline
per cent.
days
10.5
12.5
13.2
9.2
12.9
15 9
11.9
13.5
...
...
54.7
Progressive
decline
per cent.
...
10.5
21.7
32.0
38.3
46.2
54.7
60.1
65.5
....
...
8.2
No.
of cases
57
57
57
57
57
56
56
56
51
45
36
FLUCTUATIONS OF MILK YIELD WITH ADVANCEMENT OF LACTATION
211
APPENDIX B—contd.
Showing month to month lactation yields and their decline in Montgomery cows—contd.
Months.
1
2
3
4
5
6
7
8
9
10
11
Total
Average
monthly
decline
in lbs.
Average
monthly
decline
in per-
centage.
5th Lactation
Milk yeild (lbs.)
361
666
607
537
466
420
365
316
288
240
120
4,386
Decline (lbs.)
in
59
70
71
46
55
49
28
48
...
...
426
Month
to
month
decline per cent.
16 days
8.9
11.5
13.2
9.8
13.1
13.4
8.8
16.6
...
...
53.2
Progressive
decline
per cent
...
8.9
19.4
30.1
37.0
45.3
52.7
56.9
64.1
...
...
...
8.0
No. of cases
38
38
38
38
38
37
37
34
31
27
19
6th Lactation
Milk yield (lbs.)
290
596
526
452
416
388
325
286
265
207
100
3,851
Decline (lbs.)
in 13 days
70
74
36
28
63
39
21
58
...
...
389
48.6
Month to
month
decline per cent.
11.7
14.0
7.9
6.7
16.2
12.0
7.3
21.8
...
...
Progressive
decline
per cent.
...
11.7
23.9
29.9
34.6
45.2
51.7
55.2
64.9
8.1
No.
of cases
25
25
25
25
25
24
24
23
22
20
15
7th Lactation
Milk yield (lbs.)
336
613
544
489
450
394
337
315
274
243
82
4,076
Decline (lbs.)
Month
to
month
decline
per cent.
in 16 days
69
55
39
56
57
22
41
32
...
...
371
46.4
11.2
10.1
7.9
12.4
14.4
6.2
13.0
11.6
...
...
...
Progressive
decline
per cent.
...
11.2
20.2
26.5
35.6
44.9
48.5
55.2
60.4
...
...
7.5
No. of cases
17
17
17
17
17
17
17
17
16
14
12
...
8th Lactation
Milk yield (lbs.)
340
587
531
454
431
384
338
308
303
218
242
4,136
Decl i
ne (lbs.)
Month to month
decl i
ne per cent.
in 17 days
56
77
23
47
46
30
5
85
...
369
9.5
14.5
5.0
10.9
11.9
8.8
1.6
28.0
46.1
Progressive
decline
per cent.
...
9.5
22.6
26.5
34.5
42.3
47.4
48.2
62.7
7.8
No.
of cases
10
10
10
10
10
10
10
10
9
9
4
C 2
EFFECT OF SEASON OF CALVING ON MILK YIELD AND
CALVING PERIOD OF MONTGOMERY COWS.
BY
L. S. JOSEPH, G.B.V.C.,
Cattle Superintendent, Pusa,
AND
C. N. DAVE, B.AG. (BOM.),
Post-graduate Student in Animal Husbandry and Dairying,
Imperial Institute of Agricultural Research, Pusa.
(Received for publication on 23rd April 1931.)
The value of a milch breed to the practical dairyman is dependent not only
upon the quantity of milk the cow gives, but also upon the number of days she
remains in milk and dry.
With the object of studying the relationship between yields per lactation and
intervals between successive calvings, pedigree records of Farm bred Montgomery
cows (for the past 11 years) at Pusa Dairy were examined. The procedure adopted
for this enquiry was to sort out the lactation yields with respect to the month of
calving along with the number of days in milk and dry. The total number of cases
examined was 369 as detailed below :—
TABLE I.
Showing the lactation yield and calving period with respect to month of calving.
Months
January
February
March
April
May
June
July
August
September
October
November
December
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
Total Average
.
.
.
.
.
.
.
.
.
.
.
.
.
No. of
cases
34
45
42
47
29
27
25
24
21
11
30
34
369
Average
lactation
yield
4,024
3,524
4,012
3,833
3,722
4,026
3,681
3,868
3,492
4,745
3,357
3,953
3,811
Average
days in
milk
292
279
292
283
293
300
291
298
287
301
299
298
291
Average
days
dry
125
170
163
169
155
139
149
182
141
271
116
159
157
Average
calving
period
417
449
455
452
448
439
440
480
428
572
415
457
448
Order
of
rank
3
10
4
7
8
2
9
6
11
1
12
5
..
( 212 )
CALVING ON MILK YIELD AND CALVING PERIOD OF MONTGOMERY COWS
213
Inferences.
1. It will appear from the above table that the month of calving shows no
correlation with the milk yield.
2. That the average lactation yield is 3,811 lbs. in an average period of 448
days of which 157 are dry.
3. That the average calving period when calves are hand-fed is 448. Taking
283 days as the average gestation period, the average period required for conception
after calving is 165 days, i.e., a Montgomery cow is likely to conceive 165 days after
calving, yielding milk for 126 days after conception, and remaining dry for 157 days,
thus completing her average calving period of 448 days.
It may be interesting to note that the calving period is enhanced by about 25
per cent. when calves were allowed to suckle the dams. The following table gives
its details.
TABLE II.
Showing the average calving period of Montgomery cows, when the calves are hand-fed
and allowed to suckle.
No. of cases
286
369
Difference
Average No.
of days
in milk
304
291
13
Average No.
of days
dry
255
157
98
Average
calving
period
559
448
111
REMARKS
Calves allowed to suckle the dams.
Calves hand-fed.
The above Table indicates that in case of suckled calves the total calving
period is increased by 111 days comprising of 13 and 98 days as wet and dry periods
respectively.
The figures of Table I are further analysed with respect to the season of
calving.
214 THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [ I, III
TABLE III.
Showing the effect of season on lactation yield and calving period.
Season of calving
Spring
Summer
Rains
Winter
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
Total
.
.
.
.
.
No. of
cases
121
103
70
75
369
Average
lactation
yield
3,834
3,852
3,688
3,831
..
Average No.
of days
in milk
287
290
292
299
..
Average No.
of days
dry
155
157
158
158
..
Average
calving
period in
days
442
447
450
457
..
Inferences.
1. It will appear from the above Table that there is a decrease in the average
lactation yield by about 150 lbs. in case of rains calvers. This may probably be
attributed to change in climatic conditions preventing the animals from taking their
regular exercise in the open air.
2. That the average calving period along with the number of days in milk and
dry practically remains unaffected irrespective of the season of calving.
THE DIAGNOSIS OF JOHNE'S DISEASE-SOME EXPERI-
MENTAL RESULTS USING A "BOWEL-WASHING" METHOD.
BY
HUGH COOPER, M.R.C.V.S., I.V.S.,
Veterinary Research Officer,
AND
M. K. SRINIVASAN, G.M.V.C.,
Veterinary Inspector, Imperial Institute of Veterinary Research,
Muktesar-Kumaun.
(Received for publication on 21st April 1931.)
Johne's disease is undoubtedly prevalent among cattle in India to a much
greater extent than is usually supposed. Much evidence has accumulated at this
Institute to show that this disease exists in herds where there is no clinical history
of its occurrence and none suspect its existence. Animals in good condition and
apparently quite healthy may be infected, and many months at least may pass
before clinical symptoms are shown to attract the attention of owners. Such
animals are obviously a source of great danger to others in the herd as the causal
organisms of the disease are voided continuously with the faeces. The first and
most important step that must be taken if the disease is to be controlled or elimi-
nated in a herd is to detect the infected animals.
The most satisfactory test that has so far come into use in this country for the
diagnosis of Johne's disease in the early stages is the avian tuberculin test. The
double intradermal test recommended by the British Medical Research Council,
with concentrated avian tuberculin, may be used for the detection of Johne's
disease in the same way as " ordinary " tuberculin is used for the detection of
tuberculosis, and in testing a herd both the agents may, with great advantage, be
used simultaniously. The value of avian tuberculin for the detection of Johne's
disease will be seen from the results recorded below, where a number of reactors to
this agent, although not showing definite clinical symptoms, were subsequently con-
firmed to be infected.
In cases where a positive reaction to avian tuberculin is obtained, or where
animals are suspected to be clinically affected with the disease, it is desirable to
obtain confirmation of the diagnosis by the actual demonstration of the causal
organism. The usual method for the demonstration of acid-fast organisms in the
intestine of cattle is the rectal mucous membrane smear method, which is described
( 215 )
216
THE INDIAN JOURNAL OF VETERINARY SCIENCE AND ANIMAL HUSBANDRY [ I, III
in the printed circular instructions on Johne's disease, written by Dr. J. T.
Edwards, formerly Director, and issued from the Muktesar Institute, dated 27th
July 1923, an extract from which is given below :—
" It is said that in a proportion of clinically affected animals, probably about
25 per cent., the causal organisms may be discovered in smears made
from the mucous membrane of the rectum. It should be remembered
that examination of rectal smears is therefore by no means an infallible
method of diagnosis, for animals that harbour enormous numbers of
organisms higher up in the alimentary tract may fail to reveal any in
the rectum. A positive result obtained from the examination is defi-
nitely confirmatory, whereas a negative result does not necessarily
exclude the existence of the disease ".
The method recommended in the same instructions for making smears from the
rectum is as follows :—
" A piece of mucous membrane no larger in size than a pin's head is pinched
off between the free edges of the finger nails of the middle or the second
finger and thumb. This operation requires a little dexterity. After
cleansing the finger nails of one hand (the right hand usually) with
soap and water, the forearm and arm are lubricated with soap and water,
the hand introduced into the cavity of the rectum, and the rectal con-
tents emptied. The hand is introduced again after cleansing and the
tips of the middle finger and thumb held in close apposition like a pair
of pincers, and a minute area of mucous membrane is sharply pinched
off well forward in the rectal cavity. A slight difficulty now arises in
withdrawing the hand, for the sharp contraction of the anal sphincter
would tend to wipe away the fragment of membrane unless special pre-
cautions are taken. The thumb and middle fingers are therefore well
flexed so that their tips rest in apposition in the hollow of the palm,
while the index finger on one side and the third and fourth fingers on
the other are stretched forcibly outwards so as to act as dilators of
the rectum during the act of withdrawal, and protect the fragment of
membrane from interference. The fragment is usually found embedded
under a finger nail or may rest on the distal portion of the finger. If
the fragment is covered with faecal material it should be washed gently
with clean water. It is then taken up by means of the blade of an old
scalpel and well teased out on the surface of one or more glass slides so
as to form a moderately thin smear. Smears taken in this way are
usually very clean and in a very perfect state for examination, while
the animal itself is exposed to the minimum of injury. It is well to