Heifer Bull Group Article

In this years catalogue we have once again included a set of Bulls who we suggest are heifer safe. They include, Lots 55 through to Lot 58 and Lot 65 through to Lot 72, in addition to these we do have an additional Five (5) in the Work Bull Group Lot 1 and Lot 14 through to Lot 17.


It’s long been our contention that CALVING EASE has to be built into the Beef Bull Breeding Enterprise, biologically and genetically engineered, if you like. To optimise Calving Ease in the Dulverton herd we continue to-:

  • Rely upon data from years gone by that measured Pelvic Area in the retained heifers at joining and they had to measure 270 sq.cms.
  • Set minimum weight requirements to ensure preferred skeletal development at calving – – 320kg at joining and – 460kg at calving
  • Remove from the herd any female that has been assisted at calving.
  • Never allow progeny of females that might have been assisted, entry to the breeding ranks—Male or Female.
  • Select breeders-male and female with the preferred pelvic shape. That is, a pelvis with a slight roll from hip to pin bones while maintaining width through the thurls and pins. Note that natural selection for calving ease in the “wilds” has resulted in such a pelvic shape e.g. Zebras, Buffalo Wildebeests etc. The high tail settings which appear to be a lot more prevalent in Angus more recently are to be guarded against, they are a negative when it comes to Calving Ease. The correct shoulder set, that is, a “flat” shoulder well laid in with a 45° set and neck extension, are essential structural set ups not only to assist ease of calving but also to assist with mobility.
  • Select heifer bulls from maiden first calving 2 year old’s, born early in the drop and definitely unassisted.
  • Include gestation length in the selection criterion of Sires to be mated to the Yearling Heifers. Why? A bovine foetus grows at a rate in the order of 0.6 to 0.7kg/day during the last 5-6 weeks of the gestation, therefore Bulls such as Dulverton Kiwi K100 (-8.1) Dulverton Latitude L6 (-8.3) and Dulverton Lohnro L16 (-10.1) will sire calves with the genetic capability of being 4-5kg’s lighter than the average of their calving group.

Birth Weight

Notice we pay little to no attention to Birth Weight, we don’t measure it – if you can’t measure and record all calves then don’t pollute the data set by putting in incomplete sets. The Genetic Correlations developed by programmes such as Breedplan do make some very Valuable observations – the relationship Birthweight to Growth no doubt one of the best. As a General Rule the lighter the birth weight the-

  • Greater the incidence of reduced Calf Survival rates-“ Dead Calves have Distressingly Poor Growth Rates”
  • The lesser the Growth Rate and by implication the lighter the weaning weights the less the Dollar Value per head.
  • The lesser the Growth Rate the lighter the heifer when she exhibits 1st Oestrus and the lighter she will be in October the preferred time of Joining. Heifers that aren’t 300-320kg at time of joining will struggle to be 460kg at the time of Calving. As a general rule heifers in the weight range 400- 440kg simply can’t have the necessary Skeletal Development to ensure a substantial enough Pelvic Area/ “Opening” to enable safe delivery, of a healthy live calf.


  • K100. We have retained fourteen (14) K100 “N” Daughters amongst our 107 retained heifers they are progressing really well. He performs in the top 40% for 400 day Growth- vital to ensure adequate skeletal development at Joining and through to first calving. In addition he is in the top 30% for Scrotal, NFI-F, and RBY%. Based on his recent Scan data he should improve for IMF%. Seven Sons sell check out Lot 14 N27 we used him over heifers, Lots 14 and 15 both used in a Calving Ease Co-operators Herd.
Lot 14 Dulverton Northern Dancer N27
  • L006. The A.I. Conception rate in the group that L006 “Mopped Up” was very high he only sired 9 calves, we retained 3 heifers and 3 sons have made this sale group. L006 is out of a Mandy Heifer J167 who herself was out of a heifer, calving ease very much a feature of the pedigree which include T.C.Franklin and D. Uptake U91.
  • L016. Five (5) sons have made this Sale and 4 heifers retained. We are thinking L016 will have superior growth to that suggested by Breedplan his five sons in the Sale have performed at a ratio of 103 (3% above the average of the Group). Very interesting pedigree it contains one of more recent maternal champion sires in K205 (D.Queen F23) VDAR New Trend J.R.Juice Renovator and Te Mania Mittagong C65, Kilkenny K912 is from the Te Mania cow Family.
Lot 57 Dulverton Naskra N156
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