There is no such thing as a guaranteed “calving ease” breed. Some
breeds tend to have a greater number of easy calving sires…but, in all breeds,
there are “tough calving” bulls.
In all breeds there are females that cannot calve easily.
With the Piedmontese breed, we can state clearly that use as a terminal
cross, on non-Piedmontese females, gives calving ease results that are no
different than any other breed. There will still be bulls within the
Piedmontese breed, as in the Charolais, Angus, or any other breed, that are
simply hard calvers. However, USDA tests and breeder’s experiences tell us
conclusively that the average 2-copy Piedmontese bull crossed on
non-Piedmontese cows gives very acceptable calving ease.
If you choose to breed under-grown heifers (non-Piedmontese) to the
average Piedmontese bull – you should expect calving difficulty at a level
similar to using a Charolais bull on those same heifers. Managing calving
difficulty always starts with your breeding decisions ! If you have small
heifers, use a proven light-birth weight calving ease sire on them…or let them
grow out before you breed them at all.
An old rule of thumb is to service heifers the first time when they are
some two-thirds (67%) of their mature size and weight. So, if you know that
your heifers will become mature cows of about 1400 pounds – don’t breed them
until they are some 900+ pounds. This is, of course, a loose parameter. If you
are feeding heavy, those heifers will attain the weight sooner…but not
necessarily the reproductive maturity.
On a proper feeding regime, your heifers should be 65 – 70 percent of
their mature size/weight at 14 to 15 months of age.
Fat heifers (or cows) are not great choices for breeding or calving.
Bovine female conception rates are higher when the female is in average body
condition, and gaining weight (not losing weight). Fat females can have
impaired milking ability, and more difficulty calving – due to their own body
fat, and increased calf weight from excess feed.
And remember, just because a heifer is cycling doesn’t mean she is
ready to breed. Larger framed breeds, such as Simmental, will often have
heifers cycling at under 12 months of age…when they may be only fifty percent
or less of their mature size.
So, select healthy reproductively sound non-Piedmontese females to
breed to the average 2-copy Piedmontese sire and expect no added difficulty at
calving time.
There is increased management at calving time if you are breeding
Piedmontese to Piedmontese. The same general rules as above will apply – don’t
keep your cattle too fat or too thin and only breed well grown reproductively
mature heifers. But, as we have learned in recent years about the way the
myostatin gene is passed to offspring, we know we have a general mathematical
percentage to gauge calving difficulty.
In a natural breeding scenario – meaning NOT by embryo transplant –
breeding fullblood or 2-copy Piedmontese to other fullblood or 2-copy
Piedmontese seems to result is considerably less calving problems than the
exact same mating through embryo transplant (ET).
Breeding 2-copy to 2-copy will always result in a 2-copy calf.
With ET you can experience much longer calf gestation – leading to
larger birth weights. The bull calves will tend to give the highest incidence
of trouble. Knowing that a calf will gain some 2 pounds per day, inside the
dam, if the gestation length is going some 12 days longer than average the calf
will be some 24 pounds heavier at birth.
My own personal experience is that the gestation length average for
fullblood Piedmontese (natural matings) would be about 287 days. Angus state an
average of 283 days gestation, and Brahman average 292 days. Bull calves in all
breeds tend to have longer gestation; and twins tend to be born an average of 1
week early.
I had one recipient female
carrying a fullblood calf go overdue by 31 days. We did not induce that
recipient (a Holstein) just as an experiment – and she had an 85 pound heifer
calf, un-assisted ! Had it been a bull calf, who knows – it could have been a
giant ! So, the “averages” listed here are only that – averages. The range of
birth weights and gestation lengths can be wide.
A practice to consider is to induce the calving on cows
going long over-due, either ET recipient dams, or Piedmontese dams bred
naturally. However, again, this can lead to problems because induced calving
can result in backwards calf presentation, or other troubles such as failure of
the cervix to dilate properly, or delayed milk production, a higher incidence
of retained placentas, etc.
My experience has been that the calves which are going to cause you
trouble at birth will do so whether they are induced or not; but by inducing
birth you may prevent some of them from going those added days over in gestation
– leading to heavier birth weights. Inducing birth also allows you to control
‘somewhat’ when the calving will occur, so you can plan to be there…in
the daytime !
If you have a recipient cow carrying a 2-copy Piedmontese embryo calf,
and she is at 288 days gestation but not yet “bagging-up” to milk, you may
want to decide if you should wait for
some milk development before you consider inducing her.
It is always a good idea to have frozen colostrums (first milk) on hand before calving season
starts. Remember, when thawing it out, to do so very slowly…not at high heat on
the stove or microwave ! Try thawing it in the sink with warm tap water – just
immerse the container of milk, and wait. (It takes forever !)
In any case, you should plan on encountering some 20% difficult births
from 2-copy to 2-copy natural matings
and perhaps as high as 40% difficult births from ET calves – and these are
almost always with the bull calves. [By ‘difficult birth’ I mean everything
from a “hand-pull” assisted calving to
surgical-CS.]
Breeding one-copy Piedmontese to other one-copy Piedmontese results in
some 50 percent of the offspring carrying one-copy of the myostatin gene. 25
percent of the calves will carry 0-copies and 25 percent will carry 2-copies.
The greatest increase in calving difficulty will fall within that group of
2-copy calves…and will for the most part be only with the bull calves. In this
breeding scenario, expect some 20% of one-quarter of the calves to pose
added difficulty.
Breeding one-copy Piedmontese to two-copy Piedmontese will result in
half the calves being one-copy and half being two-copy. This is where we found
the greatest “erratic” calving – before we knew about the myostatin gene. We
now understand that those 1-copy calves (either bulls or heifers) were the ones
coming easy, and that some 20% of the 2-copy calves were the ones causing the
difficulty. So, in this breeding scenario, budget for 20% of half the
calf crop to be potential assisted calvings. Again, I repeat, averages are
always quoted, but seldom seem to be reality ! You may have 75% of your calf
crop being heifers in any given year … or, one year you may have 80% of the
calves with 2-copies of the myostatin gene when you cross a 1-copy with a
2-copy and the next year get 80% of them being 1-copy. But, by knowing how the gene’s transmission
will affect calving, you can be prepared.
Calving difficulty when you are producing 2-copy bull calves is higher than we would like to see,
certainly.
However, many of the Continental breeds, like Charolais and Simmental,
experienced significant calving difficulty through their early years in North
America. Breeders made great strides to improve calving in those breeds, and so
can we. It does not happen overnight.
The market for qood 2-copy Piedmontese bulls to be used as terminal cross sires on non-Piedmontese females is growing very rapidly. Breeders who want to capitalize on that market need to be prepared for some added calving difficulty now, and need to be focused on improving the calving ease in their programs for the future.
Those of you who want to use that 2-copy bull on non-Piedmontese cows –
to capitalize on the market for one-copy calves to produce the best beef in the
world – do so with confidence that your calving will be “normal”. The 1-copy
calf (either heifer or bull) out of a non-Piedmontese cow presents NO added
calving difficulty from the norm in the industry.
By Vicki Johnson