Grading-up is the process of building towards a pedigree herd by mating pedigree stallions with non pedigree mares, and subsequently mating each generation of females with further pedigree stallions of the same breed, thus increasing the percentage of pedigree ‘blood’ with each generation.
The initial females are usually referred to as Foundation Mares (or Type 1 Mares).
Grading-up is a recognized method across all species in domestic animal husbandry and is used in tiny populations to increase total numbers and minimize in-breeding.
The Australian Suffolk Punch Grading-up Registry
The ASPGUR was the vision of Marge and Dennis Candy of the then Draught Horse Centre, Inverell, NSW, with friend Bill Goddard after the import of Samford Jack 8850 from the UK and Calcott Virgo 28387 from New Zealand forming the first Suffolk Punch stud in almost sixty years. Realizing that with the tiny foundation stud, building numbers of pure Suffolks would take decades, they instituted the grading-up programme in 1997.
Traditionally, the process of grading up in animal husbandry involves using a ‘pure’ male animal of the desired species and breed, to a part-bred or non-breed female. The resultant female offspring is then bred back to a second ‘pure’ male. The process repeats through the generations until a previously designated level of ‘pureness’ is reached. At which point, usually after inspection by breed officials, the animal may be entered into the official breed stud book: or may not, depending on the final result.
No male progeny produced via grading up contributes further to the grading-up process, nor can they be entered into the Pedigree Stud Record, although in Breed Societies with separate registers for part bred animals, they may be recorded there. Any such males so produced are usually neutered. In meat animals these would be culled. It is the female who moves up through the grades, and always being put to 100% male of the breed.
When the then termed Breeding up system was implemented in 1997, by Marge and Den Candy and Bill Goddard, they were guided by the requirements of the UK Suffolk Horse Society.
- a Foundation Mare who is regarded as a Type 1 and a pure registered and licensed Suffolk Stallion produce female progeny which is a Type 2 and officially 50% Suffolk.
- A Type 2 mare put to a second pure registered and licensed Suffolk Stallion will produce a Type 3 and officially 75% Suffolk.
- A Type 3 mare put to a third pure registered and licensed Suffolk Stallion will produce a Type 4 mare and officially 87.5% Suffolk
In the UK Suffolk Horse Society grading up process, the next step was a third Suffolk Stallion put to a Type 3 mare to produce a Type 4 (87.5%) and in UK SHS parlance “may be admitted to the Pedigree register following inspection”.
Figure 1: Traditional Grading-up Process reflecting UK Suffolk Horse Society Approach
It should be borne in mind that historically, one of the major aims of the UK Suffolk Horse Society was to retrieve into the Pedigree register any mares who were otherwise ineligible having previously missed being registered. The Compilation Stud Book of the Suffolk Horse Society says:
A major innovation was the opening of a Supplementary Register in 1979 whereby a grading-up system was introduced in that a foundation mare would be selected by inspection, this being a mare of good Suffolk type but unregistered. This mare would be designed “A” and a number, and there would then be three female generations each by a registered Suffolk stallion, the progeny being designed “B”, “C” and “D”, and the female progeny of the last would then be admitted to the Stud Book proper. No male progeny could be registered until the final generation was fully in the Stud Book.
This is reflected in the current requirement:
“A Grade A (a Type 1 in the Australian Grading-up Register) or Foundation Mare will be a of Suffolk type not currently registered in the Pedigree register of the Suffolk stud-book. She must be inspected by two inspectors appointed by the Suffolk Horse Society and passed as suitable breed stock having acceptable colour, conformation and characteristics of a Suffolk. She must be a minimum of two years old at the time of inspection.”
It goes on to say:
“In exceptional circumstances where the Society sees fit the Grade register may be used as a vehicle for producing a breed animal by addition of registered blood to an initial non-breed animal over a set number of generations”.
Because of the choice of the Foundation Mare (the Type 1 aka Type A) it may take longer to arrive at the optimum “suitable breed stock having acceptable colour, conformation and characteristics of a Suffolk”. There is no universally set arrival point on grading up.
Figure 1 and Table 1 above, for example, assumes the Foundation Mare has zero percent of Suffolk Punch in her genetics. But sometimes the Foundation Mare might have some verifiable but small percentage of Suffolk Punch in her background. It is thus possible to have a Type 2 progeny who is 50% officially and 50% in reality, and another Type 2 progeny, 50% officially, but in reality 62.5%. In this latter case the Foundation Mare is 25% Suffolk Punch.
One vital aspect the Foundation Mare may bring to the process of grading-up is that of hybrid vigour. At the same time, she may contribute conformation characteristics or colouring that are true to her origins, but not to the Suffolk Punch.
As at the beginning of the Suffolk Horse in Australia when it made its contribution to Active Farm Horses, Cart-Horses, by breeders breeding to other types of light and heavy horses, the Grading-up programme is contributing to the Australian Draught to gain the outstanding Suffolk qualities both as horses and under Australian conditions. Suffolks have always been easy care, with the ability to work longer and harder and thrive on poorer quality feed, vital in drought ravaged country. Their whole coloured coats, with minimum white, helps minimise skin cancers.
Many owners have noticed a highly significant indicator – increased foal viability and strength due to hybrid vigour.
Since 2015 WoodBarn Hector S-3005, a Type 3 Stallion has been standing at stud at the Marlie Draught Horse Stud, Exeter, New South Wales. His progeny bear the unmistakable stamp of the Suffolk Punch genes to the Australian Draught Horse.
A Non-Traditional Grading up Method
While upgrading usually involves the use of purebred sires on grade dams, it is biologically valid to also use purebred dams for this process.
(Dr P. Sponenberg. Grading Up what it is and what it does, July-August 2002 issue of The American Livestock Breeds Conservancy News)
Such a non-traditional method of grading up as illustrated below, is theoretical only. Where would all those grade Suffolk Punch stallions come from? Well, one answer is from the traditional grading up breeding. Not every traditional grading up mating produces a filly foal.
Figure 2: Grading-up using 100% Suffolk Punch Mares to Grade Stallions
And Table 1 Traditional Grading-up via 100% Suffolk Stallion converts to:
A more likely scenario in a small population with a dedicated grading-up programme, would be to use both 100% Suffolk Punch stallions and mares.
Dr Sponenberg in the same article (quoted above) goes on to say:
It is also worth pondering that due to the unique genetic contributions of females (mitochondria, for example) it may actually be best for upgrading programs to insist on the use of both purebred males and purebred females in some of the generations to assure that breed-appropriate genetic material that is sex specific (Y chromosomes, mitochondria) have come from the purebred pool.
Figure 3: Grading-up using 100% Suffolk Punch Mares to Grade Stallions and 100% Suffolk Punch Stallions to Grade Mares
The 93.76% graded Suffolk Punch progeny in Figure 3, could just as easily been a Type 5 Mare as a Type 5 Stallion. The above illustration demonstrates a fundamental point: the starting point in grading up, the choice of the first Foundation Mare or Foundation Stallion, needs to be carefully selected. The hypothetical 50% Graded Suffolk Punch Type 2 Stallion, assuming he is on track in the desired characteristics, conformation and colour of the archetypical Suffolk Punch, is shortening the time needed to achieve a Type 5.
Compare the ‘levels’ or stages in Figures 1 and 2, to Figure 3. The former have five levels, the latter only four.
Time Constraints and Grading up
Grading up takes time. With the Traditional Method (see Figure 1 and Table 1), each stage requires the birth of a healthy filly foal after an average gestation of 330-340 days. The female progeny needs to grow up to at least her third year, preferably her fourth before being bred, and foaling at the end of her fourth year or beginning of her fifth. Assuming a filly foal is achieved at each ‘level’ of grading up, Figure 4 demonstrates just how long it will take to arrive at a Type 5, a 93.75% Suffolk Mare, from the starting point of the original Foundation Mare (a Type 1) bred to a 100% Suffolk Punch Stallion.
Figure 4 Minimum Time taken to achieve a Type 5 Mare providing each grading level produces a filly foal
Not surprisingly, Grading up is a long term enterprise.