Taking stock of your replacement heifers
February 2023

With the arrival of summer, staff and farmers returning from holiday or about to take a well-earned break, it can be easy to overlook your growing heifers, especially if they are at grazing, or ‘out of sight; out of mind.’

Many heifers graze off-farm, for a weekly ‘per head’ fee. Others are grazed with weight-gain contracts that stipulate target weights out to 22 months.
Some graziers will routinely weigh their heifers, others have animal health plans detailing vaccinations, drenching, trace mineral supplements, eczema control, mating management etc.

All too often, however, all the best intentions can still be thwarted by unexpected events resulting in replacement heifers falling behind in their growth and their health and wellbeing becoming compromised (Figure 1).

There is a risk that assumptions are made that stock grazing the back country are doing fine now just because they were last month, or at last yarding. In other cases, complacency can set in. Either way, heifers falling behind their breed growth target need to somehow make that weight up before they reach mating, or calving. Well-grown heifers will produce more milk, compete better in the MA herd, get back in calf, are less prone to parasitism and disease, and survive much longer in the herd.

Although heifer growth rates from birth to 22 months are curvilinear (see graph in Figure 2 – Target weights by breed & age), it is helpful to remember that heifers need to average 650–700grams liveweight gain every day to achieve their optimal breed weight by mating and calving.

 Figure 2 – How are your replacement heifers doing for their breed/age?

 Figure 1 (left) – Illthrifty heifers. Figure 3 (right) – Healthy, thriving 18-month heifers.

To safeguard your stock performance:

  • Ensure heifers are healthy, well-grown and an ‘even line’ before going to grazing; weight them, if possible
  • Vaccinations up-to-date before leaving the home farm (Lepto, Clostridial, and BVD)
  • Have a grazing contract that details your and the grazier’s expectations and responsibilities (see DairyNZ's Contract Grazing page)
  • Keep communication open with your grazier; arrange to see your heifers at least three times a year.
  • Identify any ‘tail-end’ developing early and take early action.
  • Have a plan for adverse seasonal conditions e.g. drought, high spore counts, prolonged cold/wet. Be prepared for additional feed to be delivered, and fed, to your heifers if they need it!
  • What is your contingency plan if all else fails…?!

There are few substitutes for seeing your replacement heifers at grazing for yourself. Book-in a visit for next month if you haven’t already seen them. It will be an excellent way of avoiding unexpected results. If your heifers are thriving, this will brighten your day, and you can commend your grazier – they will appreciate the acknowledgement of their hard work (Figure 3).