By Laura Kennett
Understanding all aspects of good rump
structure is an important part of being a responsible goat breeder. Breeding and selling goats isn’t
something to be taken lightly.
Each breeder bears the responsibilty of producing quality offspring that
preserve or improve the quality of the breed and match the breed standard.
One aspect of rump structure that is not
often talked about and is poorly understood is levelness from thurl to
thurl. This trait is important in
both bucks and does, as pelvic structure is a trait that is typically passed
down from generation to generation.
Because I couldn’t have said it better myself, I have taken several
excerpt from a well written article by Maxine Kinne on the structure and capacity
of the goat pelvis.
The rump
is much more than a handy place for the tail - it is integral to standing,
walking, breeding and kidding. Simple everyday functions require good pelvic
conformation. Reproduction also depends on the pelvis - breeding, carrying the
pregnancy, delivery and feeding kids. Good pelvic structure helps the goat
toward a comfortable, productive life, and selecting for it should be a high
priority.
Small
or poorly shaped pelvis often result in arthritic wear on the thurl joints and
repetitive strain to the rear legs and feet. The thurls (hips) are
ball-and-socket joints joining the hind legs to the pelvis. The shape and slope
of the pelvis determine hind leg angulation and the width between the rear
legs. Pelvic abnormalities create rear leg abnormalities, such as one or both
stifles deviated outward or post-leggedness. Too short a pelvis very seriously
handicaps the ability to give birth normally.
Pelvic
Dimensions
(taken from article by Shelene Costello)
Length
and width are the dimensions we see when we look at the rump. There is length
from hips to pins, width from thurl to thurl, and width between the pin
bones. Levelness of the rump is
also taken into account, meaning a flatter rump from side to side. This does
not mean horizontal to the ground - it means that the rump is more flat. Each
part of the rump is important unto itself and as it correlates with the whole.
Length and width should be more nearly level, not flat or rounded or steep in
slope.
Rump showing excellent levelness and width from thurl to thurl
A
good combination of pelvic length and the levelness from thurl to thurl correlate
positively with kidding ease. Widely spaced thurls result in widely spaced rear
legs. This width gives stability to the rear legs and width to the pelvic inlet
(birth canal) on the inside. Thurls should be high enough to impart levelness
of the rump from side-to-side. Increasing rump steepness from spine to thurl
compresses pelvic width and interferes with kidding ease by compressing birth
canal width. Total length of the pelvis should be medium long, a measurement
which is proportionate to the goat's size. Pelvic length equates with kidding ease better than pelvic width,
although both dimensions are important to have together.
This doe had good width from thurl to thurl, but
is less level than the doe pictured above.
Goats
with questionable pelvic structure should not be used for breeding. If she
cannot deliver or be manually delivered vaginally the first time she gives
birth, don't breed her again, and castrate her buck kids. Making pelvic
capacity an important criteria in your selection program is the most important
decision you can make with regard to the future productivity of your herd. A
short pelvis is often more steep and rounded from thurl to thurl than it should
be.
Excessive slope from spine down to thurls
also creates less width in the pelvic area
The
benefits to breeding for goats with correct pelvis structure are numerous. Longevity, better attached and better
quality udders, ease of kidding, and lower vet bills are just the obvious
benefits. Make sure you evaluate
all aspects of rump structure in your goats, and be willing to cull those who
don’t measure up. You’re doing
yourself, and many other people who might buy goats that have their heritage
from your farm, a huge favor.
