Role of reproductive technologies in reducing the time lag
associated with the commercial application of genetic discovery in the
sheep industry
J.F. Smith, I. Vetharaniam, D.G McCall and H.R Tervit
AgResearch, Ruakura Research Centre, Private Bag 3123, Hamilton
Proceedings of the New Zealand Society of Animal Production.
2000 60: 36-40
The recent and escalating emphasis on gene discovery has major
implications for genetic improvement of the NZ sheep industry. However,
the long lag phase in the dissemination of new genetic material through
current breeding structures is a major impediment to rapid uptake of the
improvements. Effective reproductive technologies are considered
necessary for achieving the desired rates of dissemination but there is
little evidence of their practical and economic values. To provide
evidence, a series of modelling exercises were undertaken. This involved
defining a particular commercial outcome (advancing the pattern of lamb
kill in Otago/Southland by 1 month without changing lambing date),
deciding on the relevant genetic trait to achieve this (terminal sires
with a 20% increase in mature size), modelling the rate of genetic gain
using a number of breeding scenarios that included artificial
insemination (AI) and multiple ovulation and embryo transfer (MOET), to
determine the time required for sufficient commercial rams to be
available to achieve the outcome. Selected scenarios were then chosen
for more detailed modelling to ascertain the economic implications to
the farm (Otago/Southland lamb finishing farm) and to the industry of
adopting the technology. The advancement of the kill pattern by one
month was worth $12,714 on the commercial farm. Based on a two-tiered
breeding system (stud and commercial) without any reproductive
technology it takes 26 years to achieve the outcome (assuming that the
animal with this genetic advantage had been identified at the start).
The use of AI at the stud level reduced this time by 11 years. The
additional use of MOET on stud ewes gave a further reduction in time of
7 years and the application of AI using stud rams at the commercial
level an additional 2 years. These results confirm the importance of
reproductive technologies in reducing the lag phase in gene
dissemination and their value to the industry. There is a need to
further refine the efficiency and efficacy of the chosen technologies.
Keywords: NZSAPAB;
AI; MOET; genetic gain; sheep; economics; breeding system;
models; growth rate; pattern of lambkill.
Last Updated 12-07-2000
