More Calves from Sperm Morphology Tested Bulls, by Greg Popplewell
Sperm Morphology not only helps rate a bull's fertility it is also an indicator of his daughters' fertility.
We all like to make sure a bull is of the right shape and structure before we use him, but what about his sperm? Evaluating Sperm Morphology involves assessing a sperm sample under a high power microscope and counting the percentage of sperm with and without normal shape and structure (% Normal). Doing this at our end has enormous benefits for commercial producers wanting more calves at their end.
An extensive industry research project called “Bull Power”, conducted by RG. Holroyd, JD Bertram, VJ Doogan, G Fordyce and JC Petherick, tested tropical breed bulls for various fertility indicators prior to joining. They then measured their calf getting ability by DNA paternity testing all calves resulting from the breeding mob they were used in. Bull Power results showed a strong correlation between % Normal Sperm Morphology and calf output under commercial Northern Australian conditions.
Furthermore, Beef CRC has recently established that %Normal Sperm Morphology in Tropical bulls is genetically correlated with female fertility traits. These female fertility traits include Heifer Age at Puberty and Days to Calving (related to Calving Interval), both key ingredients in getting a better branding rate.This is all great news for the Northern beef industry as Sperm Morphology can be measured as early as 12 months of age in Tropical Composite bulls, allowing for lab results to be used as an early indicator of not only a bull’s future calf getting ability, but also the genetic fertility of his daughters and Breeding Value of his sire and other relatives for both male and female fertility traits.
At Popplewell Composites we have all of our bulls tested independently for Sperm Morphology, as both part of an integrated Bull Breeding Soundness Evaluation (BBSE) program to assist in ensuring we are sending out bulls that get the job done. Our Sperm Morphology results are also used to assist in selection for continual improvement in both male and female fertility.We are pleased to report that testing has shown that our Hybrid Pathfinder 13-14 month old bulls typically achieve well above the Gold Standard minimum for Sperm Morphology (70% Normal), a cut off that many 2 year old purebred bulls of various tropical breeds simply fail to meet.