%0 Journal Article
%T Denatured collagen in keratin layers and smooth muscles of teats with low or high teat apex scores in Holstein dairy cows.
%A Shiroma R
%A Niyonzima YB
%A Kadokawa H
%J Anim Sci J
%V 95
%N 1
%D 2024 Jan-Dec
%M 38923230
%F 1.974
%R 10.1111/asj.13969
%X We hypothesized that teats with a teat apex score (TAS) of 4 on a 4-point scale would exhibit elevated levels of denatured collagen compared with teats with lower TAS. We procured keratin layer and smooth muscle samples from Holsteins with TAS ranging from 1 to 4, as well as from crossbred heifers (Japanese Black male and Holstein female) with TAS of 1. Teats with a TAS of 4 demonstrated increased total collagen content, higher amounts of type I collagen (the harder, thicker variant), and reduced amounts of type III collagen (the softer, thinner variant) compared with teats with lower TAS. Teats with TAS of 3 and 4 exhibited evidence of damaged collagen in smooth muscle layers compared with teats with TAS of 1. Additionally, we identified 47-kDa heat shock protein-positive fibroblasts in the smooth muscles of teats with TAS of 3 and 4. Therefore, the smooth muscle of teats with a TAS of 4 exhibited increased amounts of denatured collagen in comparison to teats with lower TAS.