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Reproduction and Gestation
Reproduction
Puberty: Early onset of puberty is an economic factor in cattle
rearing. It differs in different breeds of cattle. On attainment of puberty, the
healthy animal will come into oestrum at regular intervals. The interval between
two heat periods is called oestrous cycle. Duration of oestrous cycle varies from
18-21 days. Duration of heat or sexual receptivity ranges from 18-25 hours in different
breeds.
Onset of puberty
|
Breeds
|
Age
|
Weight
|
|
Indigenous cattle
|
20-24 months
|
80-100 kg
|
|
Jersey cross
|
15-18 months
|
160-180 kg
|
|
Brown Swiss cross
|
15-18 months
|
170-200 kg
|
|
Holstein Friesian cross
|
15-18 months
|
180- 210 kg
|
Detection of oestrum in cows can be made from :
• External manifestation including behavioural signs of oestrum
• Mucous discharge
• Turgidity or tone of the uterus
The external manifestations include excitement, loss of appetite, bellowing, reduction
in milk yield, licking other animals, mounting other animals, standing still to
be mounted, frequent urination, swollen vulva and pink and moist vaginal mucous
membrane. The mucous discharge will be ropy, elastic and clear. On rectal palpation,
cervix will be relaxed; uterus will have good tone and will be turgid.
Insemination should be done preferably at the end of oestrum, as ovulation occurs
8-12 hours after the end of oestrum. If the heat signs continue a second insemination
is advised.
Artificial Insemination
(Source: Kerala Agricultural University)
Artificial insemination in cattle
Crossbred bulls attain sexual maturity at about 24-36 months and semen collection
can be started during this period. Before collection the bull may be given 1-2 false
mounts in order to get maximum sperm harvest. From a mature bull usually two collections
can be made at an interval of 2-3 days during a week.
Artificial insemination centres in India
|
Established by
|
No. of Centers
|
|
Animal Husbandry Department
|
2538
|
|
Dairy Development Department
|
11
|
|
Voluntary Agencies
|
211
|
|
APCOS
|
185
|
(Source: NDDB)
Normal quality of bull semen used in artificial
insemination
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Mass activity
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+ + + and above
|
|
Initial progressive motility
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Above 70 per cent
|
|
Sperm concentration
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Above 8 lakhs/mm3
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Sperm abnormality
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Up to 20% with any major sperm
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|
(Maximum allowed) abnormality
|
not exceeding 5%
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Preservation of semen
1. Chilled semen is stored under refrigeration temperature of 3oC to
5oC.
2. Frozen semen.
Number of sperms required per dose of diluted semen
Chilled semen – 15 millions
Frozen semen – 20 - 30 millions
Site of deposition of semen
While chilled semen is deposited in mid-cervix using glass pipette, frozen semen
is deposited near the internal of cervix using A.I. gun.
Storing of frozen semen
Frozen semen is stored in liquid nitrogen at -196oC. The straws are thawed
in water at room temperature before use. Samples with less than 45% post-thaw motility
should not be used.
Procedure for insemination with frozen semen
• Raise the canister to the lower level of the neck of the liquid nitrogen
refrigerator so that the top of the straw in the goblet is visible.
• Using a pre-cooled forceps, take one straw from the goblet and dip
it in a beaker containing water at room temperature for about a minute.
• The straw is then taken out of the water and wiped with a clean towel
to remove water sticking on the outside.
• Hold it by the laboratory sealed end and give one or two jerks to bring
the air space towards the lab-sealed end.
• The lab sealed end of the straw is cut at right angle using a sterile
scissors. Straw should not be cut obliquely, lest the semen leak into the sheath
during insemination.
• Push back the piston of the A.I. gun and put the straw into it with
the factory sealed end down.
• Slip the sheath over the gun and fix the plastic ring over the sheath.
The gun is now ready for use.
• Thawed semen should be used within 30 minutes for getting good fertility.
Embryo transfer
Multiple ovulation and embryo transfer is also a method for genetic improvement.
Obtaining more progenies from the best cows is the objective. A cow which would
normally produce one calf a year can be made to superovulate and produce multiple
embryos. These embryos are transferred to recipient cows for further growth to full
term and calving. The genetic improvement through embryo transfer depends on the
actual superiority of the cow selected as donor, and the bull used for insemination.
Moreover, the success rate of embryo harvest and transfer are key factors while
adopting this technology. But the cost involved is very high at present. Embryo
transfer can be successfully applied to produce good breeding bulls and also to
enhance multiplication in case of endangered breeds.
The embryo transfer technology introduced in the recent past is yet another step
towards livestock development. Of the total adult female cattle population in the
State 83.4 percent is cross bred and if the cattle in milk is taken into consideration,
it will increase to 85 percent and this was made possible by the Indo-Swiss Project
and the expanded health care facilities and veterinary services.
Reproductive and productive parameters (Traits)
in Indian cattle
|
Sr. No
|
Name of the breed
|
Age at first calving (months)
|
Calving interval (months)
|
Lactation yield (kg.)
|
Lactation length (days)
|
Dry period (days)
|
Milk yield kg/day during lactation
|
|
Indian breeds
|
|
1
|
Dangi
|
54
|
17
|
600
|
300
|
210
|
2
|
|
2
|
Deogir
|
48
|
15
|
1,500
|
300
|
150
|
5
|
|
3
|
Deoni
|
53
|
14
|
810
|
270
|
150
|
3
|
|
4
|
Gir
|
48
|
16
|
1,350
|
270
|
210
|
5
|
|
5
|
Gaolao
|
46
|
16
|
600
|
300
|
180
|
2
|
|
6
|
Hallikar
|
46
|
20
|
600
|
300
|
300
|
2
|
|
7
|
Hariana
|
58
|
13
|
1,200
|
240
|
150
|
5
|
|
8
|
Kangayam
|
44
|
16
|
600
|
240
|
240
|
2.5
|
|
9
|
Kankrej
|
48
|
17
|
1,800
|
360
|
150
|
5
|
|
10
|
Khilari
|
52
|
16
|
240
|
240
|
240
|
1
|
|
11
|
Ongole
|
40
|
19
|
630
|
210
|
360
|
3
|
|
12
|
Rathi
|
40
|
19
|
1,815
|
330
|
240
|
5.5
|
|
13
|
Red Sindhi
|
42
|
14
|
1,620
|
270
|
150
|
6
|
|
14
|
Sahiwal
|
40
|
14
|
1,620
|
270
|
150
|
6
|
|
15
|
Tharparkar
|
50
|
14
|
1,620
|
270
|
150
|
6
|
|
16
|
Umblachery
|
46
|
17
|
360
|
240
|
270
|
1.5
|
|
17
|
Non-descript
|
60
|
19
|
405
|
270
|
300
|
1.5
|
|
Crossbred Cattle
|
|
1
|
H x F
|
34
|
14
|
2,970
|
330
|
90
|
9.0
|
|
2
|
H x BS
|
29
|
15
|
2,805
|
330
|
120
|
8.5
|
|
3
|
H x J
|
33
|
13
|
2,850
|
300
|
90
|
9.5
|
|
4
|
G x J
|
25
|
13
|
2,640
|
330
|
60
|
8.0
|
|
5
|
G x F
|
25
|
13
|
2,160
|
270
|
120
|
8.0
|
|
6
|
RS x F
|
29
|
12
|
2,295
|
270
|
90
|
8.5
|
|
7
|
RS x RD
|
28
|
12
|
2,160
|
270
|
90
|
8.0
|
|
8
|
RS x J
|
29
|
12
|
1,500
|
300
|
90
|
5.0
|
|
9
|
R x J
|
32
|
12
|
2,700
|
300
|
60
|
9.0
|
|
10
|
T x F
|
33
|
13
|
2,550
|
300
|
90
|
8.5
|
|
11
|
S x F
|
33
|
14
|
2,400
|
300
|
120
|
8.0
|
(Source: NDDB)
H = Hariana, S = Sahiwal, RS = Red Sindhi, G = Gir, T =
Tharparkar, R = Rathi, F = Friesian, BS = Brown Swiss, RD = Red Dane, J = Jersey
Gestation period
Gestation length is 275-285 days. Slight variation exists between breeds. Holstein
Friesian and Brown Swiss crosses have a longer gestation length than other crosses.
If gestation length exceeds 300 days, parturition will have to be induced. Few pregnant
animals may exhibit oestrous symptoms.
Pregnant cows should be given at least 2 months dry period. Transfer the pregnant
cows to calving pen at least 2-3 weeks before the expected date of calving.
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