information for each bull. This includes
estimated breeding values (EBVs) for all
production traits as well as management and
body conformation traits. Depending on the
source (country) of bulls, they often have a
breeding index like net merit (NM) consisting
of a number of economically important traits.
To do sire selection, obtain a list of all the
available bulls. The list should contain at least
20 bulls. The list should also contain the price
for each straw of semen.
The available index (NM) for bulls can be used
or an own specific herd index can also be
estimated. This could simply be a combination
of EBVs for fat and protein yield using milk
prices for fat and protein as guidelines. The
index could also be extended to include milk
production, fertility, productive life or body
conformation traits like stature. Rank the list
of bulls for the chosen index from high to low.
Pick, according to the index, the best five bulls
to be used in the herd. Use bulls randomly on
cows.
Some commercial dairies use mating
programmes because of ease of sire
selection, breeding management and better
overall breeding results. These programmes
use corrective mating to improve body
conformation traits while simultaneously
improving or maintaining production.
Rearing calves and heifers to first calving
Heifer calves are reared to replace cows
leaving the herd. Heifer rearing starts at birth
and ends at first calving. The newly born calf
must be treated like a baby, especially during
AgriKultuur |AgriCulture
the first two months of its life.
Within six hours after birth, the calf should
be helped to suckle from the mother to
consume colostrum. The cow can also be
milked by hand and colostrum fed to the calf
using an artificial teat. Colostrum is the first
milk produced after calving. It contains anti-
bodies of diseases the mother was exposed
to during pregnancy. This provides a passive
immunity to a calf during the first weeks of its
live. Colostrum also has a higher solid content
than standard milk, e.g. 24 vs. 13%, because of
higher fat and protein levels. While no direct
absorption of anti-bodies takes place after 6-8
hours, colostrum provides protection within
the stomach and should be fed for as long as it
is produced.
After 24 hours the newly-born calf can be put
in a calf pen (1.2 wide x 1.8 m long) with dry
bedding. Pens must have 1.2 m high side-
walls on three sides and a roof (1.5 m high).
Remove wet bedding once a day replacing it
with dry straw. Keep calves in the pens until 3
months of age after which heifers can be kept
in groups.
Milk feeding, using whole milk or milk replacer,
continues after colostrum feeding. Feed 2-3
litres of milk to each calf in the morning and
afternoon. Warm milk can be fed directly
after milking. While an artificial teat can be
used, calves can also be trained to drink from
a bucket. Sterilize and dry drinking utensils
after each feeding to prevent pathogens
spreading among calves. Keep on feeding
milk feeding until weaning at about 3 months
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