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As market conditions continue to drive innovation I began searching
for a terminal sire that could increase lamb feed efficiency and
growth rate. What I found was disappointing - monster sized rams
with tremendous frames and heavy bones. From past experiences
using such rams on very prolific ewes, I found that the production lost
during pre-weaning generally negated the post-weaning gains. There
must be a better way.
Cattle breeders have been selecting bulls that are feed efficient, fast
growing, moderate framed and heavily muscled for years. Every
major sheep producing country is doing the same thing - it is time the
US sheep industry caught up. If we look at other major sheep
producing nations: Australia, New Zealand, the UK, France and
Canada, we will find sires that look nothing like the breeds used here
in the US. They are medium sized, with light to moderate bone and
are heavily muscled. Popular breeds include British Suffolks, Texels,
Dorsets
and Charollais.
What does it take to make a great terminal sire?
Feed efficiency:
Feed efficiency is a critical factor in meat
production, particularly with high feed costs. Feed efficiency is
strongly correlated to lean growth and fast growth rates. Muscle
and bone contain less calories per pound than fat. Converting high
priced grains into costly fat that needs to be trimmed off is not a
viable economic model for our industry. In addition, feed
efficiency is obtained by achieving growth as fast as possible.
Each day on feed requires a certain amount of feed intake to sustain
life; growth only occurs when feed intake exceeds this maintenance level.
In the US, there are few breeders selecting directly for
feed efficiency, although there are many breeding for growth rate.
While growth rate and feed efficiency are correlated, they are not the
same thing. The primary approach American breeders use to improve
growth rates are to increase mature size. The rationale,
championed by many academics, is that lambs from large sheep can be
slaughtered at a lower percentage of their mature weight - while they are
still growing quickly and not yet depositing much fat. The end
result is increasing frame size.
Are there other ways, besides increasing frame
size, to increase feed efficiency? If feed efficiency is achieved
by fast gains and conversion to lean gain, then it stands to reason that
sheep with robust appetites (to increase daily intake) and naturally heavy
muscling would be most feed efficient. Perhaps it is not coincidence that this description fits
modern hogs very well.
Size:
Many producers believe that size doesn't matter all that much
anymore, especially with all the interest in lightweight slaughter lamb
production. If lambs are slaughtered at weights less than 90 lbs,
the ability to reach higher finish weights might not seem that important.
However, the lightweight slaughter lamb market is fickle and lambs that
cannot be finished to at least 130 lbs are of limited value as feeder
lambs. Lambs that can be slaughtered at both lightweights or traditional
weights are more valuable. Moderate framed, well muscled sheep can
satisfy both markets.
Easy gestation and birth:
Ewes weaning singles have never been profitable. In these
times, ewes weaning twins are marginally profitable, at best.
Ewes weaning triplets, on the other hand, are still turning a profit.
With high prolificacy comes increased difficulty in gestation and
obstetrics (birth). Excessive fetal loads cause stomach ruptures
and vaginal prolapses. Heavy boned lambs can be difficult to pass
through the birth canal. Lambs with long limbs tend to have more
malpresentations, such as when legs or the neck get folded backward.
As any cattleman will tell you, the ideal calf is one that has a
moderate
frame, yet is fast growing.
Vigorous lambs:
As all sheep producers know, the most important thing for a newborn
lamb is that it is up and nursing as quickly as possible.
Hypothermia and starvation are the number one killers of newborn lambs
and profits. Consequently, lambs that are "plump" at birth have
much higher survival rates thin, lanky lambs that are common with
'frame' type sheep. Such plump lambs have more brown fat, which
gives them the ability to withstand more cold and the energy to
get to their feet quickly. It has also been my experience that
smaller framed lambs, those with shorter legs,
are physically able to get to their feet much faster than those tall, lanky lambs
common to frame-type sheep. Watching a newborn frame-type lamb get to its
feet is something like watching a baby giraffe stand up - in most cases,
it is best not to watch.
After careful consideration and
research, I've concluded that what I need for my very prolific
commercial flock is a ram with the following characteristics:
-
Moderate frame, with short limbs (for easy gestations and births)
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Heavy muscling (lean gains are more efficient)
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Aggressive feeder (good appetites result in more efficient gains)
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Calm disposition (research indicates that sheep with lower stress
levels (cortisol) are faster, more efficient gainers)
-
Vigorous at birth (fewer neonatal losses)
There are a number of breeds
that are suitable, including Texels, old-fashioned Dorsets, Ille De
France and British-style Suffolks. However, one breed in
particular seems exceptionally suited to meet my needs - the Charollais.
The Charollais is a heavy muscled terminal sire popular in Europe and
Canada.
It has been specifically bred for lean gains and easy births. In
fact, the breed standard specifically requires that rams have moderate
frames, heavy muscling and a wedge shaped head, neck and shoulder. In 2009, I
purchased the Charollais ram pictured below:
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