Wednesday, August 14, 2013

Thurl to Thurl? Why does that matter?


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. 


3 comments:

  1. These articles are so helpful for me. I have been studying the past articles, too. I would be interested in seeing an article on teat development from a young doeling to final size and shape and what to look for in the teats when buying a young doeling?

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    Replies
    1. Thanks for the great feedback, Kim!
      We'll try to get an article about teat development on here as soon as possible.

      ~Sue

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  2. I know this is an old article but it is very helpful. Thanks.

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