Seven Benchmarks for Reproductive Performance
Transcript of Select Sires' Reproductive Moment Program
on DairyLine Radio, Which Aired Oct. 31, 2002
with Ray Nebel, extension specialist
and professor of reproductive management,
Virginia Tech
Today’s Reproductive Moment is with Ray Nebel, extension dairy
specialist at Virginia Tech.
Today, Ray, we are talking about benchmarking for success. You have
identified seven reproductive benchmarks. Let’s start with days open
and calving interval.
Bill, the day’s open and calving interval are the bottom line. The
goals for most dairy operations would be a 13 1/2 month calving interval,
which correlates to 130 days open. Days open is the time from when
she calves to the time she conceives. When you add the nine months
of pregnancy, you get her calving interval, the time interval from one calving to the
next. The goal would be a 13 1/2 month time period. We don’t really
get involved to evaluate the herd or make changes until we get to
about a 14 1/2 month calving interval. Now, an important point is that
we have to see where we are today. With a herd that at maybe
16 months calving interval, it is unrealistic to say that we are going to drop it to
13 1/2 months very quickly. Our goal might be to drop 30 days every
12-month period. That could be achieved reasonably, and gives
us something to shoot for, something that can be attained without getting too frustrated.
Another benchmark, days to first service.
That is really the question of when do we start breeding. This is an area many of
us fall short on, as far as when do we get the program started. In
fact, in the United States today the average is probably right
under 100 days. We really could get going at 75 days. At 75 days
after she calves, we want to have the first service or first A.I.
breeding put in. This gives her plenty of time for her reproductive
involution to get the tract back in shape, get her out of the
negative energy balance from her high milk production peak, and
get her back on to reproductive success.
Touch on heat detection and conception rates.
We need to determine when the cow is in estrus so we can breed her,
and improve our success rate during that insemination process. The heat
detection rate goal of catching 2/3 of the cows in heat at efficiency really
doesn’t sound very good, but it is kind of like playing baseball:
if we can hit 66 percent of the balls, we are doing a really good job.
The average right now is running somewhere under 40 percent, so 2/3
of the cows would be a nice goal, and the best dairies are getting
that goal. With conception rate, 45 percent would be a nice goal.
Right now the national average is probably 30 to 35 percent. Again,
the best herds are running 50 to 55 percent, but when it gets down
to 30 percent, we need to do an evaluation of where can we improve,
where can we tweak the system to increase our conception rates.
How about reproductive culling?
Reproductive culling is really removing the cows that didn’t make it through
the program. We would like to have fewer than five percent of the heifers culled each year because they were reproductive failures. Right now,
nationally, the percentage is running probably at about eight percent of the
cows that we cannot get pregnant within a reasonable, or economic
time period. When that level gets to ten percent, we really need to
evaluate the system to get that back in line.
And, Ray, to wrap things up, the final benchmark is pregnancy rate.
The pregnancy rate is the conception rate times heat detection, divided
by 21 days. Now, 21 days is the average estrus period, or the time
of one estrus to the next. Out of each 21-day period that we have to get the heifers
in heat, how many do we catch in heat and how many do we get pregnant?
That is a new parameter, probably just introduced in the past few years,
but it is a very useful parameter defining the speed at which we get
cows pregnant.
Ray Nebel, extension dairy specialist at Virginia Tech.
Copyright 1996-2002 Select Sires Inc. Last updated 31-Oct-2002.
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