There are various reasons that farmers milk OAD, but many
will tell you that their herds reproductive performance lifted when they switched
from TAD milking.
To find out whether OAD herds really do have better reproductive
performance, we compared the reproductive performance of OAD herds against herds
that milk TAD for the whole season using the results from the 2014 to 2016
The results are in
Averaging the performance across all three seasons, the
results show that herds milked OAD all season do, on average, have better
reproductive performance than herds milked TAD all season.
- 6-week in-calf rate - 10.4% higher
- Not-in-calf rate - 4.8% lower
- Herd 3 week submission rate - 7.7% higher
- First calver 3 week submission rate - 8.2% higher
- Conception rate - 7.9% higher
the three seasons, the average 6-week in-calf rate of the OAD herds was 75% versus
the TAD average of 65%. This
result puts the OAD herds in top quartile of reproductive performance in New Zealand.
The OAD herds also achieved a lower not-in-calf rate,
despite a slightly shorter mating length (about 4 days). Not-in-calf rate is an important figure as the number of
non-pregnant cows impacts your ability to cull the cows you want to.
Show me the money
average 6-week in-calf rate of the OAD herds is just short of the industry
target of 78%, but their 10.4% higher 6-week in-calf rate is helping to bring
in the dollars. Using DairyNZ’s economic multiplier of $4/cow for every 1% increase
in 6-week in-calf rate, this 10.4% difference is worth approximately $4,160 per
this figure nearly doubles when you add in the benefit of a lower not-in-calf
rate. DairyNZ estimates that every 1% decrease in
not-in-calf rate is worth $10/cow in the herd. This makes the 4.8% lower not-in-calf
rate of the OAD herds worth approximately $4,800 per 100 cows in their herd.
For a 400
cow herd, this higher reproductive performance would be worth around $35,840!
Consistent use of OAD
There were 30 herds that were OAD for all three seasons. Their results follow very much the same trends
as those reported above. This indicates
that the reproduction benefits from milking OAD all season can be maintained
year after year.
Food for thought
There is a strong indication that milking once-a-day for the
whole season has beneficial effects on herd reproductive performance. This is good news for those of you already
milking OAD, but doesn’t mean everyone has to go OAD to get good results.
In the spring 2016 season, 11% of the herds across the
country* had a 6-week in-calf rate the same or higher than the OAD
average of 75%.
However, for those who are struggling to get good
performance in a TAD system due to challenges that cannot be overcome through
other management practices (e.g. long walking distances etc.), OAD might be a
way to improve reproductive performance.
Before switching to OAD, you need to consider if the OAD
system is right for you. It’s important
to remember that OAD has milk production impacts, and often involves other farm
system adjustments such as stocking rate.
It’s recommended that you seek professional advice before making the
Reproduction results averaged across the 2014-2016 seasons
for OAD and TAD herds
*Detailed Fertility Focus report herds only - OAD, TAD & milking system unknown herds
To be classified as a herd that is OAD or TAD for the whole
season herd, they needed to herd test three or more times a season and have the
same milking regime (OAD or TAD) at each test.
To allow comparison of herds with quality reproduction records, only
spring calving seasonal herds with a Detailed InCalf Fertility Focus report in
MINDA were included. For each season
analysed (2014, 2015, and 2016), a herds results were excluded if they did not
meet the selection criteria for that season.
In total 75 OAD and 76 TAD herds were analysed. To remove any geographical influences, the TAD
herds included were situated in similar geographical locations as the OAD
herds. The OAD/TAD herds were located
all over the country.
DairyNZ resources for OAD milking
If you have any questions about this article, get in touch with the Repro Team at firstname.lastname@example.org.
The reproduction measures analysed were calculated from data and information
entered by herd owners and collected by LIC & DairyNZ. Accuracy of
the results reported here is subject to the accuracy of the data entered.