The Dulverton Selection Criteria
Maternal traits are of paramount importance.
Fertility: Heifers are AI’d for a cycle and run with a bull for two cycles. Cows are joined for three cycles plus three – five days to enable the bulls to settle once introduced. Importantly any female not in calf at pregnancy check in late March early April is culled and sent to slaughter. Greg and Sally cannot afford to compromise on fertility, after all as Jim Bradford ‘Guthrie Centre’ Iowa has stated ‘fertility is the Governor of Growth’.
Calving Ease: Heifers are joined at a live weight of 320kg on 1st October condition score 2+ – 3-, they are grown along to ensure they weigh 450kg when they commence calving the following July, that is as two year olds, again in condition score 2+ – 3-. Importantly these weights must be achieved by each individual they are not averages. If a female has trouble calving she is immediately culled from the herd and any calf that has to be assisted for what ever reason is reared and sold to the abattoirs, never to be used as future breeders. Greg and Sally believe that if the minimum growth targets are met by each and every female then the skeletal development including the pelvis will be sufficient to ensure adequate ‘room’ for the foetus to grow and develop and for the birth to occur naturally. These targets also ensure the female portion of the seedstock herd has sufficient ‘lean’ growth to ensure adequate growth is passed onto the future generations of bull progeny. Greg and Sal see the maiden females that is, weaner heifers through to when they are joined as two year olds as the most important category of stock on the property.
Structural Soundness: Females are continually culled for structural soundness problems. Interestingly Greg and Sal don’t have a policy of discarding cows as they reach a nominated chronological age. To the contrary if cows continue achieving the goals set then they stay in the herd. Many older cows tend to pass structural and longevity traits to their offspring, this is particularly important to our bull clients in that it helps reduce breakdowns amongst young bulls.
Mature Cow Weight: Cows must be functional at pasture they must also have the ability to pass on growth genes, Greg and Sal prefer their cows to weigh in the range of 550 – 650kg at weaning. They certainly don’t tolerate any lighter than this but are happy to keep cows even heavier given their understanding of the fact that cattle do have a tendency to reduce in frame size and growth potential unless selection pressure is maintained.
Weaning Weight: The weaning weight targets are as follows; heifers 270 – 300kg, bulls 300 – 350kg given the New England pasture rearing system.
Sale Bull Selection Procedure: Greg and Sal select and catalogue their sale bulls during week 3 of April. At this time they must have had a daily gain of 1.0kg/day since birth, the odd individual e.g. younger sons from very good cows, or bulls that have been excessively ‘ridden’ maybe included with a growth rate in the 0.95kg/day plus range. The bulls must also fulfil a scrotal circumference requirement of 36cm – no compromise, fertility is so important. At this time Dick Whale scores the bulls for structural soundness using the GTS system, and two highly respected commercial cattlemen James and Ted Laurie, class the bulls. Any bulls they wish to remove are taken out. Muscling and natural doing ability plus soft pliable skin with slick hair are important selection criteria for the program.