The Myth of Hybrid Vigor in Meat Goats
To perform the analysis I used data from nine years of Angelo State University Meat Goat Performance Tests. The years utilized were 1999 through 2007.
During that time over 1,000 goats completed the test. Over half of those goats were Fullblood Boers, almost 20% were pure Spanish, a few were Kiko or Kiko crosses, another 20% were Boer x Spanish, with the balance being Purebred Boers (31/32nds Boer and higher crosses).
Breed Results 1999 to 2007 |
||
Breed |
# Tested |
ADG |
Purebred Boer |
57 |
0.603 |
Fullblood Boer |
584 |
0.593 |
7/8 Boer |
7 |
0.587 |
Average |
1005 |
0.560 |
15/16 Boer |
35 |
0.548 |
5/8 Boer |
129 |
0.542 |
3/4 Boer |
9 |
0.536 |
Spanish |
175 |
0.457 |
7/8 Kiko |
4 |
0.438 |
Kiko |
5 |
0.419 |
For years I have read and heard
about hybrid vigor in livestock, but have had difficulty reconciling those
accounts with my own experience raising goats since 1995.
When I started out in the goat business my herd was a mixture of Kiko,
Boer x Kiko, Boer x Angora, Boer x Spanish, Spanish, and Boer does. All
our bucks were Fullblood Boers.
I gained quite a bit of experience over the years with various breeds and
hybrids. Every year we would cull our does based on various factors like
their worm resistance, productivity, mothering ability, resistance to
mastitis, etc.
Pretty early on the Kiko and Spanish does were removed from our herd.
The Kiko does were good and attentive mothers for the most part, but even
when crossed to our Boer bucks, raised smaller kids then the others, and
seemed particularly susceptible to developing mastitis and/or pendulous
udders that kids could not nurse from.
They and their offspring were the first to disappear from our herd, and at
this point there is not a drop of Kiko blood in any of our goats.
The ASU test results seem to confirm this, although the number of Kikos
that have ever been tested there is minuscule. The ones that have been
tested as a group have done very poorly, and the cream of the Kiko crop
gained weight at a rate that was barely above average.
The Spanish does were also a disappointment. Some had a nasty habit of
giving birth than promptly returning to the herd, leaving their kids to
fend for themselves. Even the ones who were attentive mothers tended to
wean smaller kids.
Again, the test results backup my observation. The Boer x Spanish kids for
the most part gain weight at a rate that is below average. They gain
weight more quickly than a Spanish kid, but do not outgain fullblood Boer
kids.
My understanding of hybrid vigor is that the offspring are supposed to be
superior to both the parents, but that simply does not seem to be the case
with meat goat hybrids.
The one group of goats that outgained their Fullblood Boer sires were the
Purebred Boers. Most of the Purebred Boers on the test have come from one
of two herds, mine and ASU's. Most years those are two of the top herds
participating in the test.
I theorized that the source rather than hybrid vigor was the cause of the
result, so I compared the Purebred Boer results to the results of the
Fullblood Boers from those two herds. Even then the Purebred Boers still
outgained their 1/2 brothers that were Fullblood Boers by a significant
amount.
Which brings me to the last group of non-Fullblood Boer does I started out
with, the Boer x Angora does. I loved those does. They were great mothers,
they raised big, fast growing kids, and most of the purebreds remaining in
my herd are their descendants.
In fact, my buck that won the test this year has a small amount of Angora
blood to compliment his Boer genetics.
Most of the Purebred Boers you see outperforming the Fullblood Boers are
in fact Boer x Angora Purebreds, not Boer x Spanish. The lower percentage
Boer hybrids are nearly all Boer x Spanish.
It appears that when it comes to weight gains, crossing meat breeds does
not result in hybrid vigor, just a mediocre performing compromise.
Crossing a meat breed to a breed like the Angora on the other hand does
seem to result in a kid that grows faster than either of its parents.
