News

In January 2004 Deer Improvement purchased nineteen stags highly ranked for venison growth rate. These animals had been raised under a variety of conditions at different studs so could not be compared alongside each other.

In order to measure comparative performance it was necessary to have each stag generate a number of offspring raised under the same conditions and accurately identified using DNA parentage testing. The relative growth rates of the progeny would then provide an accurate assessment of the genetic value of the sires.

A total of seven weighings are planned from pre-weaning to the yearling stage. The first two weights, one in early January and the second at weaning, have been used to calculate the genetic merit of the stags in terms of impact on weaning weight.

Ideally we would like to identify the genetic merit of the stags relative to the average commercial hind in New Zealand, but this has not been established. Later this year we will have enough genetic links to enable our Breeding Values to be listed on the same scale as the Invermay Sire Referencing Scheme which uses as its base the average Invermay hind in 1990. Until then we can only compare what we have measured, so all stags are listed relative to the lowest ranking of the group.

We have found that the genetic merit of the stags ranges over twelve kilograms (11.8 to be precise) at weaning in late February. The names of the stags and their individual weaning weight evaluations are listed below:

What do these figures tell us?
If Carl was mated over hinds of genetic merit equivalent to his own, his progeny would be twelve kilos heavier at weaning than progeny from Midnight mated over hinds at his level. However if both were mated randomly over the same group of hinds, Carl’s offspring would be weaned on average 6 kilos heavier than Midnight’s. This is because only half the genes in the offspring come from the sire.

What are the implications for farmers?
The data collected and analysed to date indicates support for the widely held view that there is a wide range of genetic diversity for growth rate in red deer in New Zealand. Because we don’t yet have an accurate measure of the genetic merit of the average commercial hind we cannot precisely quantify the genetic advantage of our top stags, but we can use some reasonable assumptions to explain the genetic gain that is available to those who seek to improve the efficiency of venison production.

For example, we do know that Carl is twelve kilos better than Midnight. Midnight is a pure Eastern ranked highly in his stud of origin. It would be reasonable to assume that Midnight is more highly ranked for growth rate than the typical commercial hind carrying genes from feral ancestors and perhaps some English bloodlines selected for antler traits. If we assume that Midnight is say 6 kilos better than the average hind, it follows that Carl is (6+12) 18 kilos ahead. That is, by lifting the genetic merit of commercial hinds and stags to the level of Carl, a farmer could lift his weaning weights in late February by 18 kilos.

While this is happening the Deer Improvement genetic improvement programme will be using technologies such as embryo transfer to capitalise on the availability of objective evaluations to make further gains. By using the top ranked stags to generate replacement hinds and sire stags farmers can expect to make similar rates of gain.

Where does it end?
 Long term experience in dairy, beef and sheep farming shows that genetic improvement shows no sign of slowing even after many generations of selection.

For the full pedigrees of the stags please refer to the Deer Improvement website (www.deerimprovment.co.nz) or for more information contact any member of the Deer Improvement team.