19 February 2021
To treat or not to treat non-cycling cows
31 August 2020
Republishing articled appeared in Dairy Farmer Aug 2020 edition.
Written by: Samantha Tennent, DairyNZ developer and In-Calf program
Non-cycling or anoestrous cows are a challenge. Cows are in a race against time to recover from calving and begin cycling again in time for mating – when we want cows cycling as early as possible to improve their chances of getting in calf early in the mating period.
Doing premating heat detection provides early warning of non-cyclers and time to do something, if required.
Short-term measures to treat noncycling cows include treating them with hormones.
There are no right or wrong and no one-size-fits-all approach. Each farm needs to assess its non-cycler situation individually and formulate a plan.
Farmers might question whether treatment is cost effective and whether to treat before or after mating starts.
If they wait till after mating begins some cows might have started cycling and fewer might require treatment but, for some cows, a delay in treatment might affect conception. Both queries have been addressed in New Zealand research.
The financial benefits of hormone treatment were explored in 2010 research. The results were conclusive. Treating cows is more cost-effective than doing nothing and that is valid over a wide range of milk payments and responses to treatment. That confirms investing in the treatment of non-cycling cows provides worthwhile returns to farmers.
A clinical trial in the late 1990s assessed whether hormone treatment before the start of mating or leaving treatment till 16 days after mating began would achieve better results.
The outcomes show treatment eight days before the planned start of mating increases the number of cows that conceive in the first three weeks. It also reduces the time from the start of mating to conception by 7.5 days.
Positively, the conception rate of cows mated following treatment is the same as cows mated at their first spontaneous cycle after calving. The trial found identifying and treating non-cycling cows before mating significantly improves their reproductive performance in seasonally calving dairy herds.
Both studies build the case that treating non-cycling cows is more cost-effective than not treating. They also confirm when spending money on treatment, starting early will reap the full treatment benefits and return on investment.
There are many reasons why cows don’t cycle. If a herd is experiencing large numbers of non-cycling cows each season there is likely an underlying issue that needs to be addressed with a vet and adviser.