Max Newsome, Northern Tablelands Local Land Services Livestock Officer
Spring joining is just around the corner so now is the time to consider the fat score of your bulls. In drought years they are typically not at the top of the priority list but the fat score of both your bulls and cows is going to determine this year’s conception rates.
Bull fertility is positively correlated to their fat score, as bulls with a low body fat score can result in sub-fertility and a decreased libido.
It takes 64 days for a bull to produce semen so the ideal time to assess the bulls’ fertility is nine weeks prior to joining.
Bulls should be on a rising plane of nutrition prior to joining and be at a fat score of three when they are joined. To increase the body condition of bulls, it is recommended to feed a diet that has energy levels of 9-12 MJ/kg DM and 12-14 % protein.
Grains such as barley and oats are a good source of energy in the diet. Protein can be added into the diet with products such as dried distillers grain (DDG), protein meals and manufactured pellets. Remember to feed fiber roughage when grain is being included in the diet.
Semen testing can either be done prior to bull sales to give you the opportunity to replace sub-fertile bulls or nine weeks prior to joining. Assessing the semen is even more important in bulls that are used in single sire mating groups as a sub-fertile bull will have a large impact on your bottom line.
All bulls being joined must be free-moving, active and in good store condition. Bulls should be drenched, treated for lice and up to date with their 5 in 1 and vibriosis vaccinations. They may need vaccinating against leptospirosis and three-day sickness in some areas.