Hi Everyone
I am from New Zealand, in the USA at the moment. In NZ you time the
onset of mating with when you plan to start calving the following
year. Calving dates are determined by numerous factors but are mostly
focused on matching you herds' peak feed demand with your expected
peak grass growth (which is mid spring in NZ). Thus you want all of
your herd well into production by this time. On the other hand you do
not want to calve too early as that you will not have enough grass
growth to meet your demands (some farmers offset this by feeding
supplement early spring until the grass kicks off).
So for example, we start calving mid July through to mid September
(remember our seasons are opposite to you!) with a mean calving date
of around early August. The peak feed demand/grass growth occurs
roughly around the end of September. And then mating begins around
mid October. We do artificial breeding to all cows for the first six
weeks (two cycles) and then the bulls go out until January to catch
any returns. This keeps the calving period compact.
Common practise is to tail paint cows 3 weeks (one cycle) before
mating starts so that non-cyclers can be identified and monitored.
After the first 3 weeks of mating, cows that still haven't cycled at
all can be treated with a hormone to be induced into heat. This can
be an effective way of getting cows in calf early to ensure a compact
mating period.
New Zealand farmers are strict on cows when it comes to fertility,
there is not much allowance for late calvers. Thus cows that are
empty/open or are due to calve very late are culled from the herd.
In conclusion, mating periods should be based on your planned calving
period, not so much on how long your cows have been cycling for.
Granted this is an important factor in getting your cows back in calf,
but if you are a seasonal farmer you need to be strict with your
calving patterns to ensure you get productive lactations out of your
animals.
I really recommend NZ genetics for these farming systems as this is
the pressure these genetics have been up against for decades, and they
have had to do it on grassed based diets. Visit
www.newzealandgenetics.com for more info.
I hope this has helped
Good luck,
Michelle.
On 5/16/06, Emilynorris1@aol.com <Emilynorris1@aol.com> wrote:
>
>
> Clay,
>
> My method was to make sure every cow was ready to re-breed as an ongoing
> herd health protocol before the breeding season. You get to know who needs
> help with uterine involution, nutrition, etc. and be pro-active. On day 1
> of breeding season, everyone is fair game unless she has metritis. Some
> cows will get an 80 day wait period, some will rebreed only with 10 days.
I
> felt that if she was in heat and it was breeding season, she was fair game.
>
>
> Best Regards,
>
> Emily Norris
> Evergreen Valley Graziers
> Vermont, USA
>
>
