Morphology, adipocyte size, and fatty acid analysis of dairy cattle digital cushions, and the effect of body condition score and age

Abstract

The digital cushion is an essential part of maintaining a healthy foot, working to dissipate foot strike and body weight forces and lameness from claw horn disruption lesions. Despite the importance of the digital cushion, little is known about the basic anatomy, adipocyte morphology, and fatty acid composition in relation to age, limb position, and body condition score. In total, 60 claws (from 17 cows) were selected and collected from a herd, ensuring that body condition score data and computed micro-tomography were known for each animal. Digital cushion tissue underwent histological staining combined with stereology, systematic random sampling, and cell morphology analysis, in addition to lipid extraction followed by fatty acid analysis. The results describe digital cushion architecture and adipocyte sizes. Adipocyte size was similar across all 4 claws (distal left lateral and medial and distal right lateral and medial) and across the ages (aged 2-7 yr); however, animals with body condition score of 3.00 or more at slaughter had a significantly increased cell size in comparison to those with a score of less than 2.50. Of 37 fatty acid methyl esters identified, 5 differed between either the body condition score or different age groups. C10:0 capric acid, C14:0 myristic acid, C15:0 pentadecanoic acid, and C20:0 arachidic acid percentages were all lesser in lower body condition score cows, whereas C22: 1n -9 erucic acid measurements were lesser in younger cows. Saturated fatty acid, monounsaturated fatty acid, and polyunsaturated fatty acid percentages were not altered in the different claws, ages, or body condition score groups. Triglyceride quantities did not differ for claw position or age but had decreased quantities in lower body condition score animals. Digital cushion anatomy, cellular morphology, and fatty acid composition have been described in general and also in animals with differing ages, body condition scores, and in the differing claws. Understanding fat deposition, mobilization, and composition are essential in not only understanding the roles that the digital cushion plays but also in preventing disorders and maintaining cattle health and welfare.

Identifying cow – level factors and farm characteristics associated with locomotion scores in dairy cows using cumulative link mixed models

“…During periods of excessive weight loss, fat is mobilised from the digital cushion that hence loses much of its force dissipating capacities. Cows may develop impaired mobility as the decreasing dimensions of the digital cushion lead to increased pressures exerted on the corium, the germinative epithelium and the distal phalanx which promotes the development of traumatic claw lesions [87,88]. This reasoning is further underscored by our result that overconditioned cows experienced 0.77 times lower odds for a higher LS compared with animals in optimal condition.…”

Prospective cohort study of the association between early lactation mastitis and the presence of sole ulcers in dairy cows

“…7,25 A recent postmortem study of digital cushion tissue found that cows with BCS > 3.0 at slaughter had significantly greater adipose cell size than cows with BCS < 2.5. 57 Another possible explanation for our BCS findings is that cows that develop SU in early lactation are likely to mobilise more fat due to the pain they experience and the associated reduced dry matter intake.…”

“…Low BCS and loss of BCS through lactation is known to be a risk factor for formation of claw horn disruption lesions and there is evidence that this is related to the thickness of the digital cushion 7,25 . A recent postmortem study of digital cushion tissue found that cows with BCS > 3.0 at slaughter had significantly greater adipose cell size than cows with BCS < 2.5 57 . Another possible explanation for our BCS findings is that cows that develop SU in early lactation are likely to mobilise more fat due to the pain they experience and the associated reduced dry matter intake.…”

Changes in plasma fatty acids profile in hyperketonemic ewes during early lactation: a preliminary study

“…Arachidic acid (20:0) is a SFA whose concentration differs between bovine tissues such as muscle and kidney adipose tissue 45 – 47 . In the study of Newsome et al 45 investigating the digital cushion of dairy cows, adipocytes size and concentration of arachidic acid were positively related to BCS. In the present study, the two groups did not differ in BCS.…”

“…In the present study, the two groups did not differ in BCS. However, the NEB induces fat mobilization from functional fat reserves such as the digital cushion 45 . The reduction of arachidic acid in hyperketonemic group may be related to an increase of β-oxidation induced by palmitoleic and vaccenic acids.…”