Association of <i>TLR4</i> and <i>CARD15/NOD2</i> polymorphisms with SCC in Holstein–Friesian cattle

• Main Authors: K. Wojdak-Maksymiec, K. Mikołajczyk, K. Prüffer
• Format: Article
• Language: English
• Published: Copernicus Publications 2015-07-01
• Series: Archives Animal Breeding
• Online Access: http://www.arch-anim-breed.net/58/293/2015/aab-58-293-2015.pdf

<i>Mastitis</i> is one of the most important dairy cattle diseases which results in economic losses in dairy production. <i>Mastitis</i> cases can be classified as subclinical or clinical. All forms of <i>mastitis</i> lead to changes in milk composition and induce an increase in somatic cell count (SCC). SCC is a very important and basic indicator of udder health. An increase in SCC is usually caused by the immune response to the invasion of pathogens contributing to <i>mastitis</i>. The aim of this study was to investigate associations between the polymorphisms of selected genes (<i>TLR4</i> and <i>CARD15/NOD2</i>) whose products are involved in the identification of pathogen-associated molecular patterns (PAMPs) during the innate immune response to infection, and immunity to <i>mastitis</i> expressed as SCC. The genes under study were also examined for epistatic effects as well as effects of interactions with parity and stages of lactation. In all the studied classes, allele G of <i>TLR4</i> had a favourable additive effect with negative values, contributing to a lower lnSCC. Allele A of <i>CARD15/NOD2</i> had a desirable additive effect which varied with time and the changing internal environment during lactation. With regard to the dominance effect, allele A of <i>CARD15/NOD2</i> was found to be significantly associated with a higher SCC in milk in the first lactation and in the third stage of each single lactation. Moreover, statistically significant epistatic effects were found, in particular additive–additive and dominance–additive interactions were favourably associated with SCC which was lower than expected in the case of no epistasis.