DNA Results Validate and Assist Suncrest’s Herd Selection Programme – August 2013

Whilst in Canada attending the World Galloway Congress, fellow Canadian Galloway breeder John McIllwraith introduced Bob & Karen to the Igenity Profile System whereby using the power of DNA, Igenity can help to understand and manage the potential for cattle to perform and transmit traits of economic importance. Igenity profile scores traits such as:

  • Carcass Composition (yield grade, rib-eye area and back-fat thickness);
  • Carcass Quality (marbling and quality grade);
  • Maternal and Reproductive Traits (heifer pregnancy rate, stay ability and maternal calving); and,
  • Average Daily Gain (residual feed intake and daily gain)

and allows breeders to determine how their herds’ genetics compares with Galloway breed/country benchmarks available in the Igenity database; and allows them to sort and rank their cattle based on traits that are most important to them.

In June 2013 Bob & Karen took hair samples from some selected White Galloway breeding cows and bulls with a view to assessing the genetics of their herd, how it rated with country benchmarks for the breed, and whether important traits of progeny of selected matings were improved.

The resulting Igenity Profiles for their animals were very interesting but to fully understand the benefits they need to be read in conjunction with the Igenity Results Key for Beef which can be found on the Igenity web site – www.igenity.com

Briefly the profiles use a score of 1-10 with the values in between reflecting the relative difference expected in animals compared to contemporaries with an Igenity Profile score of 1. Higher scores are not necessarily better i.e. the lower the score for Residual Feed Intake, the less the animal needs to achieve the same gains, but most traits e.g. Average Daily Gain, the higher the better. As an example, if Animal A has an I-Score of 7 for Average Daily Gain (in effect 0.25kg/day), and Animal B has an I-Score of 3 (in effect – 0.06kg/day); and if Animal A gains 1.55 kg/day, then it is predicted that Animal B will gain Animal A’s gain less the I-Score equivalent difference (0.25-0.06=0.19kg/day), giving Animal B an Average Daily Gain of 1.36kg/day.

The following table gives the Igenity results from selected Suncrest cows and bulls, and shows averages for each trait as compared with an average result from a Canadian Galloway breeder, and the whole of the USA.

At a glance Table 1 shows that Suncrest’s cows score a much lower Residual Feed Intake (IScore 3.9 or 0.59kg/day) than the North American average (I-Score 5.7 or 1.0kg/day), requiring on average 0.41kg/day less for the same gain than their N. American counterpart. In addition Suncrest herd’s Average Daily Gain (I-Score 5.9 or in effect 0.20kg/day) exceeds the North American average (I-Score 5.3 or 0.16kg/day) by 0.04kg/day, (with minimal hard feed supplements).

The table also shows that Suncrest’s Carcass Quality traits (Tenderness, Marbling and Percent Choice) compares favourably with the North American average, as generally does the Carcass Composition and Maternal & Reproductive traits. See Tables 2, 3, 4 & 5 –comparing Suncrest’s distribution (My Animal Distribution in tables) for traits – Residual Feed Intake (RFI), Average Daily Gain, Tenderness & Marbling, with that of USA Galloways (Benchmark Group Distribution in tables) respectively.

More importantly when comparing the Igenity Scores of Suncrest’s Sire/Dam matings with the I-Scores of their progeny, a significant improvement in most traits is noticed, thereby validating Suncrest’s herd selection and mating programme (see Table 6).

Table 6 shows that whilst the Residual Feed Intake I-Score for the progeny is greater than those of their Dam (a negative), the Average Daily Gain is the same as or an improvement on both parents. Carcass quality of progeny shows an increase in Tenderness over that of both parents, and progeny have a higher I-Score for Marbling and Percent Choice than their Dams. Meanwhile Carcass Composition traits for the progeny are the same as or an improvement on their Dams, and the four Maternal & Reproductive trait scores of the progeny are an overall improvement on the average scores of both parents.

Parent

Progeny

Unfortunately Suncrest’s parent to progeny sample is small at this stage, as a lot of the progeny had been sold prior to doing these Igenity Profiles. Plans are to have the Profiles done for replacement heifers, a new Stud Sire, and this year’s crop of calves, thereby providing a larger, and more significant database, thus allowing more conclusive results and better information for breeding decisions.

However whilst the parent to progeny sample is small, definite improvements are evident, and the Igenity profiles, coupled with an assessment of animal structure, physique, temperament and a number of performance measures, will enable better decisions into the future on which Dams & Progeny should be held or culled, and which Sires should be used over which Dams.

In summary, the Igenity Scores are now being used to provide more informed herd management decisions, in conjunction with other selection criteria. The I-Score traits most important to Suncrest’s herd and farming operation are now being selected, and more weight is being placed on the traits considered most relevant to Suncrest’s herd improvement objectives.