Breeding

DUDAUMAN PARK

Breeding Meat Goats Since 1998

BREEDING STRATEGY

OUR PURPOSE

Our objective is to provide commercially productive seed-stock to goat meat producers. Dudauman Park’s goat breeding is directed at turning off the best possible fit-for-purpose meat production goats. To these ends, we select and breed on the basis of both visual/structural traits (visually assessed) and genetic traits (as estimated by the Kidplan system). Structural, carcase and reproductive traits are always top priority. Worm resistance is important for some regions but not others; colour and adherence to breed standard are secondary priorities; full-blood, purebred or percentage breed content is important in some operations. To meet these objectives, we breed with the purebred, full-blood, percentage or composite animals that deliver the best production genetics. Our husbandry is as close to commercial arrangements as we can achieve while collecting the data required for selection.

DATA

We use data extensively to assess animals for relative merit and best purpose. In the course of its life, Dudauman animals typically have the following data collected on them :

  • Parentage (often confirmed by DNA)
  • Birth Weight and Kid vigour
  • Udder, teat and mothering scores
  • Weights at …
    • Weaning stage
    • Early post-weaning stage
    • Post-weaning stage
    • Yearling stage
    • Hogget stage
  • Scrotal circumference
  • Eye muscle and fat depth
  • Worm egg counts
  • Visual assessment scores

ESTIMATED BREEDING VALUES

www.sheepgenetics.org.au/Breeding-services/KIDPLAN-Home

This data is processed in the Kidplan system at Sheep Genetics in Armidale to generate “Estimated Breeding Values” (EBVs). Kidplan EBVs compare the animal’s genetic merit to the benchmark for that trait and so give a ranking of that animal relative to others. The EBVs and Indices indicate how well the animal’s average progeny will perform.

  • Birth Weight EBV (‘BWT’) is based on measured birth weight of kids adjusted for age of dam and litter size. Where birth weights are not available it is estimated as a correlated trait from weight measurements taken as the kid matures.  The lower the EBV, the lighter is the estimated progeny birth weight potential.
  • Weight EBVs, including Adult Weight (‘AWT’) describe the animals’ genetic merit for growth rate.  A more positive EBV means the animal is genetically predisposed to faster growth rate.  Weight EBVs are available for weaning (100 days), post-weaning (250 days), yearling, hogget and adult ages (‘AWT’).
  • Eye Muscle Depth EBV (‘EMD’) describes the merit of an animals’ genes for eye muscle depth at a constant weight – a positive EBV means a genetically thicker-muscled animal, and one that will have slightly more of its lean tissue in the higher-priced cuts. YEMD is the EBV for the yearling stage.
  • Reproductive EBVs describe the merit of animals’ genes for kidding and/or

marking rate. ‘YSC’ describes the scrotal circumference of males. ‘NKB’ is the EBV for Number of Kids Born. ‘NKW’ is the EBV for Number of Kids Weaned.

  • Worm Egg Count EBVs (‘WEC’ or ‘FEC’) describe the value of animal’s genes for resisting worm burdens – a combination of being genetically less likely to pick up worms and being better at getting rid of them. ‘YFEC’ is the EBV for worm resistance at the yearling stage. Note the more negative numbers indicate higher resistance.
  • In-breeding Percentage (‘IB%’) describes the degree of in-breeding in the animal’s pedigree.

INDEXES

Selected EBVs are combined, with necessary statistical adjustments, into “Indexes” which summarize the relative genetic merit of each animal for a defined breeding purpose. At Dudauman Park, we focus on two key indexes :

  • The Carcase Plus Index (C+) combines post-weaning weight, fat depth and eye muscle depth EBVs to predict an animal’s genetic suitability for high growth and muscle depth. It selects for purely terminal characteristics. The C+ index is being replaced by the Terminal Carcase Plus (TCP) index.
  • The Boer $ Index (B$) combines several terminal and reproductive EBVs (mainly early weights, eye muscle depth and number of kids weaned) to estimate an animal’s genetic merits in a self-replacing herd, where both terminal production and replacing breeders are important. It is a ‘balanced’ index selecting for a combination of terminal, maternal and worm resistance characteristics.

PERCENTILES

For each trait or index, Kidplan publishes “percentiles” that show how that animal ranks compared to all others in the database. For example, a goat described as “in the 5th percentile” or “Top 5%” ranks amongst the best 5% of all animals in the database for that trait or index.

TYPES

To aid choice of the right animals for different purposes, we group the animals on their genetic profiles (EBVs and Indexes) into four ‘types’ : Terminal, Maternal, Dual Purpose and Worm Resistant.

  • A ‘Terminal’ sire has a genetic profile that will tend to produce kids suited for slaughter rather than reproduction. [e.g. Carcase Plus Index, Eye Muscle Depth]
  • A ‘Maternal’ sire has a genetic profile that will tend to produce progeny suited for reproduction. [e.g. Number of Kids Born, Number of Kids Weaned, Scrotal Circumference, Ease of Kidding]
  • A ‘Dual Purpose’ sire has a genetic profile that is strong in both Terminal and Maternal areas.
  • A ‘Worm Resistant’ sire will tend to throw progeny with a higher resistance to intestinal worms. [Worm Egg Count]

In some operations, it is also important to know the breed content, typically whether or not it is Full-blood.

  • A ‘Full-blood’ buck has a pedigree that goes exclusively and directly to animals imported from South Africa, without external infusion, and should be registrable with either of the two Australian breed societies.
  • A ‘Purebred’ animal contains a very high proportion of the core breed (typically Boer) but has some minor external infusion that prohibits it from being called full-blood.
  • ‘Percentage’ or ‘Composite’ goats are infused or crossed with genetics from outside the full-blood cohort.

VISUAL/STRUCTURAL ASSESSMENT

For visual and structural assessment, we use a visual classification or score to assess, cull and rank each mob. The Visual Score (or ClassiMate Score, CM) is a ranking, out of a possible 10 points, that indicates the visual and structural correctness of a particular animal as determined by an assessor. The ClassiMate program – a visual livestock assessment tool, currently in testing mode, calculates the score from observations of key visual traits (Meat, Feet, Structure, Character, Reproduction) using industry accepted weightings for each observation.

NOTE 1 : The CM scores currently used are a trial of the ClassiMate system which is in the ‘beta testing’ stage at this time. We welcome feedback on the scores and associated graphics on Auctions Plus and on pens. Please pass any feedback to Angus at angus@classimate.net or Colin at colin.ramsay@bigpond.com

NOTE 2 : As these visual assessments are subjective, not quantitative, It is important to consider which assessor made those judgements as each will have personal biases and opinions. In particular, assessment that has been done by the Vendor, not an independent assessor, might well be a fair representation of relative visual merit within the group but is subject to vendor bias.