Hi Guys
I see there has been a bit of talk about crossbreeding on the forum.
I thought I might add my opinion as we have a crossbred herd in NZ in
the top 1 percentile on a national scale for BW and PW, and we have
some crossbred bull graduates from LICs sire proving scheme.
Firstly there are two distinct differences with crossbreeders between
the USA and NZ. ON AVERAGE, NZ crossbreeding farmers are a lot more
structured and the difference between crossbreeding and pure breeding
is minimal, compared to USA crossbreeding farmers who can be very
blarze with their breeding programs. Also NZ breeders are fortunate
to have a database that records and evaluates crossbreds and
purebreds, and is comparable ACROSS all breeds i.e. a Holstien can be
compared to a Jersey or cross with the same index.
In NZ, we (and most farmers) crossbreed to gain advantages such as
hybrid vigour, less inbreeding, best of both breeds, access to a
larger genetic pool etc. Most crossbreeders use proven high genetic
merit bulls from breeding companies. So their crossbred stock still
all have high genetic merit like a purebred farmer, but the only
difference is their animals arent pure!! Until about 6 years ago,
there were top genetics that were not available to other NZ farmers
because these genetics were crossbreeds and breeding companies only
sold purebred semen.
Most crossbred cows are no worse in conformation than a lot of
purebred herds. Pedigree herds on the other hand usually have the
best conformation due to corrective breeding practices, but sometimes
the focus is on confo too much and production is only average. There
seems to be a decreasing proportion of pedigree herds in NZ and the
purebred bulls being offered by breeding companies are not always from
pedigree herds, more and more are comming from commercial herds, be it
purebred or crossbred.
Hybrid vigour is at its maximum in the first cross, and it is still
apparent in the 2nd and 3rd crosses. After that, if you continue to
use high genetic merit bulls, the hybrid vigour will "die away" but
that doesnt mean your cows are not as good, they will continue to
improve each generation (provided you use top genetic bulls). This is
exactly the same to pure breeders who use top bulls, they obviously
dont have hybrid vigour, yet if they use top bulls their cows will
continue to improve.
I have seen in the USA that crossbreeding does not have the reputation
as that in NZ. I don't understand completely the drive behind it yet
- perhaps farmers want to use another breed to increase fertility in
their purebred holsteins??? But there doesnt seem to be much
strategic planning behind it. Purhaps some farmers want to save costs
of breeding and go and buy a random bull for natural mating instead of
doing AI??? I am sure there are hundreds of other reasons for there
being so many below-average crossbreds in the USA dairy industry.
With the right breeding practises, crossbreds (be it 1st, 2nd or 3rd
crosses) shouldnt be at a disadvantage when compared to purebreds in
terms of production and confo.
Michelle.
