DNA testing of bulls
During the next two years the programme of DNA testing for White Park cattle will transfer from Microsatellite markers to SNP markers. This requires a change in our procedures in order to verify parentage and comparison with the breed profile. The new procedure that is being introduced with immediate effect applies when a bull calf is kept entire and is intended for breeding:
- As soon as possible after birth please collect hair samples from the calf, his dam and his sire (each in a separate envelope marked with the donor’s name and ear number) and post these to the Society office.
- Each sample should consist of at 40 – 60 hairs pulled from the switch of the tail with follicles (roots) attached. Using pliers might make it easier to extract the hairs.
- If hair samples are not on file when the bull inspection is requested this may prohibit the calf from being inspected and possible registration.
This leaflet from Weatherby’s gives further information on how to take a hair sample:
Your attention and cooperation is much appreciated. If you have any queries about the new procedure please get in touch with Jane at the office on [email protected]
Inspection of bulls
Inspection of bulls for possible breeding takes place when the animal is approximately two years of age.
Approval and classification of bulls results from three primary evaluations;
- visual inspection by Society inspectors,
- predicted merit by analysis of pedigree and
- linear assessment of the animal.
Inspection of a bull to include the DNA analysis costs £100. If you would like to arrange for a bull inspection please contact the Secretary, Jane Hampson, on [email protected] or visit our Forms page to download the application form.
Linear Assessment of Bulls
Full results on all bull inspections are available on Linear assessment results 201231 This information was updated on 31 December 2020 to give further details on whether the bull was graded above average, average or below average during linear inspection, whether its semen is available via AI, when it was inspected and if it is proven to breed true to White Park pattern colour.
When inspecting a bull for possible registration a series of measurements is applied and these are processed to give a value for various aspects of conformation, each expressed as % above or below breed average.
The Excel table above shows values for weight, length, pelvic and scrotal size. On the basis of these factors bulls are classified as ‘Pass Plus’ or ‘Pass’ or ‘Fail’. Bulls which fail are not listed. A further column now has been added for colour marking. These results allow breeders to select a bull or bulls which suit their particular requirements.
In some circumstances they may wish to choose a bull with the highest overall rating. In other cases they may wish to find a smaller bull with a large pelvic rating, or they may want a long bull if their cattle have become too small or stocky. Yet again, some breeders place a higher priority on strong colour marking, although we do not yet fully understand the inheritance of strength of colour marking.
Advice on interpretation and use of the tables is available through the Society. Please contact the Secretary in the first instance.
A Call for Quality Bulls
The sustained success of the breed relies to a large extent on continuing production of quality bulls and Council places a high priority on this aspect.
The membership as a whole is encouraged to retain more bulls for breeding. Currently, about 66 bulls are used each year (62 for natural service and 4 by A.I.) plus others for cross-breeding. Assuming a bull on average probably has an effective breeding life of three or four years, it can be estimated that maybe 16-20 bulls are needed annually for pure breeding to replenish the breeding pool.
Members individually are advised to keep entire only bulls of the best breeding. Although more bulls are needed, it would be counterproductive for the breed to be flooded with sub-standard animals. Therefore Council urges you to retain only bulls that are sired by a superior herd sire (look at bull evaluations on the website) and are out of a cow that consistently rears a good, well-grown calf. Please also take advantage of the opportunity to discuss breeding policy with the breed inspectors when they visit.
The registration procedure for a White Park bull includes several different aspects.
The primary purpose is to validate his purity and parentage, and this is achieved by DNA testing and reconciliation of his result with those of his recorded parents and comparison with the breed profile.
The second objective is to evaluate his breed characteristics and type, and this is achieved by visual inspection by inspectors appointed by the Breed Society.
The third objective is to predict his mature quality through a procedure known as linear assessment as part of the programme to improve the value of White Park cattle in a range of systems within the livestock industry.
The ‘bull evaluation’ table shows the results for this aspect of the registration procedure. White Parks are a late-maturing breed, but bulls are presented for registration at about two years of age. They may have been reared on production systems which vary from intensive feeding to extensive grazing. The purpose of linear assessment is to remove the effects of age and management in order to show the genetic potential of the bull, although the ultimate proof will be the quality of his progeny.
Because the White Park is adapted superbly to extensive grazing systems, the Society does not wish to see young bulls forced by high feeding, and therefore does not impose minimum weight limits. The linear assessment procedure is the best way to allow bulls to be reared ‘naturally’ without prejudicing their eligibility for registration.