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The study was
carried out on 3168 Karan Swiss cows maintained at NDRI,
Karnal during 1965 to 2000. The disposal rate of female
calves and heifers in various age groups namely upto 1
month, 1-3 month, 3-6 month, 6-12 month, 12-18 month and 18
months to AFC was investigated over the generations
(paternal and maternal generations).The mortality rate in
different age groups was found to be 8.5, 5.3, 1.5, 2.0, 1.0
and 1.5% of herd strength, whereas culling rate was found to
be 0.1, 0.1,1.1, 2.3, 1.7 and 12.6% of herd strength. The
overall disposal from birth to first calving was found to be
38.1% in Karan Swiss herd. Parity-specific disposal over
both the paternal and maternal generations revealed low
incidence of disposal after first parity in the first
generation, whereas, in later generations incidence of
disposal was more. Impact of disposal on milk production
performance studied by comparing the average expected
breeding values (EBV) of existing, disposed, culled,
retained and newly entered animals over the years indicated
high EBV in the initial years than later years. This could
be due to small herd size, low replacement rate and high
incidence of involuntary culling.
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