research facilities like a dedicated dairy herd ( s ) and breeding scientists .
Local dairy cattle breeding geneticists provide a valuable service to dairy farmers participating in the national milk recording scheme by estimating the genetic merit of dairy cows , heifers and bull for dairy farmers . Farmers are provided annually a herd genetic profile indicating the genetic merit of each animal . Also included are genetic trends for production traits for the herd in comparison to the national herd . However , expanding genetic analyses for other traits is hampered by the non-availability of records like LW and fertility traits other than calving interval . The possibility of estimating genetic parameters for LW , body condition score and fertility traits based on service records has however been demonstrated .
The reason for the lack of breeding and selection research in the dairy industry stems from the fact that breeding requires long term studies . The progeny of sires selected today only complete a first lactation four years later . This should be followed by at least 3-4 generations to enable determining the lifetime effect of a specific breeding programme .
A general misconception exists among nutritionists , veterinarians and research managers that breeding studies within dairy herds are in opposition to short-term feeding trials . Breeding research requires accumulating records of cows over time . Statistical programmes for genetic analyses are adapted to accommodate missing records . Dairy herds used for nutritional research should in any event have a well described breeding objective as a standard operating procedure . It would be easy to include a second breeding objective on a portion of the dairy herd to be able to compare a specific breeding objective ( or treatment ) within the control herd . Records accumulated over time could be made available to geneticists .
Practical experience has shown that limited information is available from commercial herds as records usually do not include a control treatment . Often there is a lack of pedigree information while breeding strategies may have changed over time . Dairy farm breeding objectives are also affected by economic factors and managers which may result in the termination of specific breeding strategies .
Large vs . small cows There is an ongoing debate in South Africa about large vs . small cows . Farmers often indicate breeding towards medium framed cows as part of the herd ’ s breeding objective . At present there is little scientific basis for this and is probably related to the emphasis breed societies put on this trait . Local dairy farmers are not keen to select for higher milk yields mainly because of perceived unfavourable correlations to fertility and LW . With the amount of information currently being recorded on the progeny of service sires , perceived negative correlations can be overcome by applying selection indexes based
AgriKultuur | AgriCulture
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research facilities like a dedicated dairy herd(s)
and breeding scientists.
Local dairy cattle breeding geneticists
provide a valuable service to dairy farmers
participating in the national milk recording
scheme by estimating the genetic merit of
dairy cows, heifers and bull for dairy farmers.
Farmers are provided annually a herd genetic
profile indicating the genetic merit of each
animal. Also included are genetic trends for
production traits for the herd in comparison
to the national herd. However, expanding
genetic analyses for other traits is hampered
by the non-availability of records like LW and
fertility traits other than calving interval. The
possibility of estimating genetic parameters
for LW, body condition score and fertility traits
based on service records has however been
demonstrated.
The reason for the lack of breeding and
selection research in the dairy industry stems
from the fact that breeding requires long
term studies. The progeny of sires selected
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