Laurie's Blogs.

This week I read a blog.  It was highlighting lessons learned from engineered ligaments.  I don’t want to deep dive into the article.  I just wanted to share one take away point and see where or if it fits with our canine population.

“48 hours of high estrogen level was enough to decrease the stiffness of ligaments without change in collagen content.”

This made me think about breeders and their habits in regards to screening radiographs for hip dysplasia.  Does a dog’s estrus (heat cycle) impact hip laxity? 

One article had the following information:

“For many years we breeders have been assuming that there regularly were differences in observable hip joint laxity between films made in or near estrus and those made in complete anestrus (not close to a heat cycle). We also told each other that to get the best picture and the best chances of “passing OFA”, we should take the pictures in the afternoon, after the dog had been exercised and “toned up”, on a dog with good muscle development from regular exercise over a longer period of time, not within a couple weeks of estrus or several weeks of pregnancy, and without sedation. This was based on intuitive supposition, and the OFA even made statements to the effect that they were true concepts (Reed & Keller, undated brochure, approx 1999-2000; and Canine Practice 1993, volume 18).”¹

http://siriusdog.com/effect-of-estrus-on-hip-conformation/  

However, a 1997 article debunked this idea. “Although significant fluctuations of oestrogen and progesterone occurred throughout the phases of the oestrus cycle, neither statistically nor clinically significant changes in coxofemoral joint laxity were documented.”²

Antech Imaging Services however does recommend waiting 8-weeks post lactation or 16-weeks post whelping, before performing a PennHIP evaluation.³  Hormones released during the birthing process (relaxin) and during lactation (prolactin) can increase hip laxity and presumably subjective hip evaluation.

What else did I find in the literature?  Nothing.  Nothing on this topic whatsoever.

As someone that works with a large number of breeders, I can now pass along this information and feel fairly confident that I did my due diligence in researching the topic to formulate an evidence based opinion / suggestion.

I hope others find this informative as well!

All the best!

Cheers,  Laurie

References:

1. Lanting, F.  Effect of Estrus and Other Factors on Apparent Hip Joint Conformation. http://siriusdog.com/effect-of-estrus-on-hip-conformation/  Accessed February 2, 2022.

2. Hassinger KA, Smith GK, Conzemius MG et al. Effect of the Oestrus Cycle on Coxofemoral Joint Laxity. Vet Comp Orthop Traumatol 1997; 10(02): 69-74.

3. Antech Imaging Services. Estrus & Pregnancy. The female heat cycle (estrus) and hip screening.  https://antechimagingservices.com/antechweb/estrus-pregnancy   

 Accessed February 2, 2022.