Tuesday, 27 January 2015

Significantly higher genetic progress with new reproductive technologies

By Jørn Rind Thomasen, VG & Senior Scientist Anders Christian Sørensen, Aarhus University
Systematic use of reproductive technologies for the best females gives up to 34% higher genetics progress – without increasing the rate of inbreeding.
Calculations show that we can increase the genetic progress significantly by using new reproductive technologies systematically in the best females. And even without an increase in rate of inbreeding. But it requires that the sires of sons are used widely and equally. Even though the technology is expensive, the investment is profitable due to the higher genetics progress.

At the moment VikingGenetics is working at various models to ensure a more integrated use of MOET/OPU in the breeding scheme for all breeds.

Donor heifers are selected more reliably with genomic selection
Over the last decades the use of MOET used to increase the number of progeny by the best females in the population. However, the challenge has been that the selection of high index heifers for flushing solely was based on pedigree information and thus with lower reliability. The reliability in the selection of bull dams was increased when selecting them older when they had their own information from first lactation. This increased the generation interval and led to a lower genetic progress.

By using genomic information the donors can be selected more reliably even as heifers. Genomic selection will also make it possible to select between full and half siblings from MOET and OPU more efficiently. Therefore our study shows that MOET/OPU is more effective combined with the use of genomic selection.

Increased genetic progress
Compared to a reference breeding scheme with genomic selection of bulls only, we can increase the genetic progress by up to 34% by using MOET/OPU (table 1). In a breeding scheme with 50 sires of son the genetic progress will thus be improved by 16 to 28 percent. The increase from the 16 to 28 percent comes from an expansion of the flush programme from 50 to 200 donors, i.e. from 250 to 1000 born bull calves from MOET/OPU.

Furthermore our analysis shows that there is a positive interaction between improving the reliability of the genomic breeding values, flushing even younger bull dams and obtaining better flush results at the same time.

Table 1: Genetic progress, increase in inbreeding and profitability of introducing various reproductive techonologies in the breeding work
 
# donors


# sires of sons


Relative increased genetic progress


Relative rate of inbreeding


Profitability


0*


50


0


100


-


50


25


+23%


258


47


100


25


+28%


230


30


200


25


+34%


209


18


50


50


+16%


128


30


100


50


+22%


123


20


200


50


+28%


120


13


100


100


+14%


69


8


200


100


+20%


66


6



* Reference scheme
The number of sires of sons influence the increase in inbreeding the mostThe inbreeding impact – or the genetic cost that comes from using a more intensive breeding strategy – varies a lot between the breeding strategies shown in table 1. This means that by choosing the best strategy we can use the best females more intensively without it affecting the rate of inbreeding significantly.

An expansion of the donor programme will reduce the increase in inbreeding, but the largest positive effect comes from using more sires of sons. The donor programmes with 50 sires of sons increases the rate of inbreeding by 20 to 28 percent per generation compared to a corresponding reference plan without the use of MOET/OPU. An increase of this extent is, however, acceptable.

Investment in reproductive tecnologies is profitable
In all the shown breeding schemes in table 1 the profitability is calculated as the increased profit divided by the increased costs in the breeding scheme by using reproductive technologies. It is assumed that the genetic progress is expressed in a population of 500,000 production cows. This means that the breeding scheme with 100 donors and 50 sires of sons will return the investment 20 times over 15 years. The cost of progeny from MOET/OPU has been set to 1000 Euro per live calf, but even at a cost of 1500 euro per calf, the investment in MOET/OPU will give a positive return. The calculations, however, assume that 100% of the value of the benefit for the entire cow population is used to recover the investment. In case only half the cow population will use the improved genetic, the profitability will be halved.

Dictionary

MOET
= Multible Ovulation and Embryo Transfer – transfer of embryos after hormone treatment increasing the number of embryos for transfer

OPU
= Ovum Pick Up – extracting unfertilized eggs that will afterwards be fertilized in a laboratory

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