Review/Oorsig Volume 22, Issue 02 - Page 5

Volume 22 • Issue 02 • 2018 enter the compromised skin to cause excessive inflammatory response when conditions are not ideal (wet, poor hygiene, etc.). Multiple studies have shown that feeding a combination of zinc, manganese and copper as amino acid complexes and cobalt as cobalt glucoheptonate to dairy and beef cattle can limit the impact/ occurrence of digital dermatitis, while also improving claw integrity and decreasing the incidence of lameness and other claw disorders (Gomez et al., 2014; Kulow et al., 2017). The impact of trace minerals on hoof integrity extends beyond the skin. One primary initiator of the inflammatory pathway is via the toll-like receptors (TLR). The primary outcome of the TLR pathway is the synthesis of pro- inflammatory metabolites (De Nardo et al., 2015). In a study conducted at the University of Illinois (Osorio et al., 2016b), cows fed zinc, manganese and copper as amino acid complexes and cobalt as entire inflammation pathway. Both acute and chronic inflammation, regardless of whether it is infectious or non-infectious, influence vascular integrity and function by creating endothelial dysfunction, compromising vascular tone, thrombosis and vascular remodeling. Oxidative stress associated with inflammation can dysregulate the production of nitric oxide (NO), essential for the endothelial cells. This leads to the production of superoxide anions and peroxynitrite (ONOO-) which become very harmful for the blood vessels. Zinc plays important roles in the protection of these cells by increasing anti-oxidant status [zinc-mediated glutathione de novo synthesis, increasing superoxide dismutase (SOD) activity] and by down-regulating inducible nitric oxide synthase (iNOS) – derived NO formation. iNOS production is instrumental during the inflammatory response but it becomes harmful Figure 5 - Protein "Stitching" of the Tight Junctions Between Two Enterocytes. Zinc plays an important role in maintaining the physiological function of the gastrointestinal tract (Alam et el. , 1994) cobalt glucoheptonate, in place of s ulfate forms, had greater expression of one of the TLR genes. However, these animals also had decreased expression of genes coding for downstream metabolites in the hoof corium. This reduction in gene expression reflects less in the corium of cows fed complexed organic trace minerals, as well as potential readiness to respond to an acute insult if necessary. Cows fed complexed organic trace minerals also had greater expression of genes that regulate the antioxidant response, which can have obvious, positive impacts on an inflammatory response (Wang et al., 2015). Taken as whole, one possible explanation for these observed results (i.e., reduction in claw disorders, such as digital dermatitis) is that cows fed complexed organic trace minerals more effectively initiate the beginning state of an inflammatory response without initiating the if it is not regulated – known as “aberrant” production of NO. Zinc-mediated regulation of iNOS expression is affected by the regulation of NF-ktransactivation. Researchers in Germany have been able to reproduce some of these pathways by exogenous added zinc. Instead, there is an observed decrease in expression of downstream metabolites in cows fed complexed organic trace minerals. This may be due to production of more structurally sound tissue in these animals, resulting in less tissue damage. Inflammation and the Gastrointestinal Tract Dehydration, malnutrition, cold stress, and oxidative free radicals can all cause the epithelial lining to be weakened, potentially leading to a pathogen invasion into the animal’s body. Heat stress and associated reduced feed intake 5