LTV

Because the White Swiss Shepherd is genetically similar, if not identical, to the German Shepherd, I thought to include LTV research based specifically on the German Shepherd breed. LTV is "[developed] at the transition of the vertebral spine segments (e.g. lumbar spine / sacral bone)" (Verein für Deutsche Schäferhunde (SV) e.V. & Tellhelm, 2015).

Accoridng to Gluding et al. (2021) "The genetic analysis of this study confirmed the moderate heritability of LTV, formerly estimated by Wigger et al. (2009), which is a key determinant of the efficiency of breeding selection. To investigate LTV types I to III with respect to an overlapping genetic basis, genetic parameters were estimated multivariately, and the obtained additive genetic correlations among the LTV types...Because positive additive genetic correlations between the different types of LTV indicate a shared genetic background, all types of LTV, including LTV type I, need to be considered for future breeding programmes and selection schemes.

There are different scorings of LTV: 0, 1, 2, 3, and 4. "LTV1 (divided median crest) is the mildest form of LTV, where a depression is seen in the median crest between the first and second vertebrae. The body of the sacrum is always normally fused. 

LTV2 is a symmetrical type of LTV, as changes are similar on the right and left side. The vertebra can resemble more a lumbar vertebra or a sacral vertebra. In the body of a vertebral space is usually visible. LTV3 is a non-symmetrical type, where right and left side differ in shape. One side resembles lumbar vertebra and the other sacral vertebra. The body of the sacrum is usually abnormally fused, and a space between sacral vertebrae is visible. LTV4 is conformationally the most severe type of LTV, where the shape of the S1 is similar to normal lumbar vertebra (lumbarization, L8) or L7 is totally fused to the sacrum (sacralization, L6) (Lappalainen, 2024). LTV has been associated with increased risk of hip dysplasia, as proven by Berg et al. (2025) "It has been reported that asymmetrical LTV is related to rotational alterations of the pelvis, which might promote the development of asymmetrical canine hip dysplasia (CHD) grades [7, 8]. In a recent study the authors identified an association between both symmetrical and asymmetrical LTV and hip dysplasia in dogs." 

"It has been shown that dogs with LTV have a higher frequency of severe CHD. A higher percentage of sacroiliac joint degenerative changes was observed in dogs with no signs of LTV and in working dogs" (ScienceDirect, 2015).

So, what does all of this mean? 

 LTV is a hereditary spinal anomaly common in Shepherd-type dogs, where the vertebra at the junction of the lower back and pelvis is malformed. This condition can lead to premature degeneration of the lumbosacral junction and potentially cause Cauda Equina Syndrome (CES). LTV is categorized into types (0-4) based on severity and symmetry, with Type 1 being the mildest and Type 4 the most severe.

Genetic analysis confirms LTV's moderate heritability, emphasizing the importance of considering all types in breeding programs to improve the breed's health. Positive genetic correlations between different LTV types suggest a shared genetic background. LTV has been linked to an increased risk of hip dysplasia (CHD), particularly asymmetrical forms, and a higher frequency of sacroiliac joint degenerative changes. Early diagnosis and treatment, including radiographic screening, are crucial for managing the condition and its potential complications.

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