animal production - CSK Himachal Pradesh Agricultural University ...

Selection of a Good Dairy Cow
Av.gestation period 280 280
(days)
Av. lactation yield(L) 4000 6150
305 days)
Age at first calving 38 36
(months)
Distinguishing Has straight top line Ruggedly built and
Characters level rump and sharp posses large
withers. Head shows feeding capacities
a double dish. Animals and udders. The
are inclined to be nervous head is long,
and sensitive, often vicious. narrow and straight
Capable of utilizing with slightly rounded
roughages efficiently. Can withers.
with stand tropical and
humid climate better
Composition of milk
Fat (%) 5.5 3.5
Protein(%) 3.9 3.1
Lactose(%) 4.9 4.9
Ash (%) 0.7 0.7
Total solids(%) 15.0 12.2
An average crossbred cow should have age at first calving 24-30 months, weight at first calving 300 kg, lactation
yield (300 days) more than 2,800 L, service period 60-90 days, dry period 60 days, calving interval 12-14 months and fat
percentage 4.0-4.5. For achieving these characteristics, the local cows should be mated with exotic bulls of Jersey breed to
produce crossbreds, having 50 per cent exotic germplasm (halfbreds) in this state. The best local cows with a good milk
yield should be mated with progeny-tested bulls of exotic breed having high genetic potential for milk yield. These crossbred
cows (halfbreds) should be mated with crossbred bulls (halfbreds) so that the level of exotic germplasm is maintained
around 50 per cent.
Reproduction
Crossbred heifers attain puberty around 12 months of age whereas the local heifers attain the same around 30-35
months. The age at sexual maturity in crossbred heifers is about 15-18 months as against 30-35 months in the local ones.
The weight of the heifer at the time of their first insemination should be 225-250 kg for Jersey crossbred and 250-275 kg for
Holstein Friesian.
The average duration of estrous cycle is 21 days with a range of 18-24 days. The duration of heat is 24-36 hours
in crossbred cows and 12-24 hours in local cows. The symptoms of heat can be sub-grouped as early heat (0-8 hours),
mid-heat (12-18 hours) and late heat (24 hours). The symptoms of heat are given below:
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