Interpretive Summary: Associations between immune competence phenotype and feedlot health and productivity in Angus cattle
By: Anne Kamiya, MS
Improving the health and wellbeing of cattle without antibiotics is both necessary and challenging. Vaccinations and stress reduction increase resistance to illness and disease, however the genetic selection of animals with a strong immune system is also important. Estimated breeding values (EBVs) for cattle include highly sought-after phenotypes such as improved growth and reproduction. However, phenotypes for disease resistance or increased immune competence (IC) are not counted, categorized or included in such databases.
The authors of this recent Journal of Animal Science article studied the relationship between IC and health and productivity in Angus cattle. They assessed IC by identifying animals that had strong antibody and cell-mediated immune responses to vaccinations during the weaning period. Calves were then categorized as having low, medium or high IC. The majority of animals tested (over 75%) had average IC responses.
Cattle were evaluated over their lifetime until feedlot finished, for productivity and general health. Disease incidence and mortality was highest in the low IC group and lowest in the medium and high IC groups. There were no mortalities in the high IC group. There was no correlation of IC status to productivity parameters such as average daily gain.
The results of this study suggest that selecting for animals with strong IC may become a valuable phenotype to identify. The authors state that the differences in cost between low IC and high IC animals in this study were $103/head versus $4/head, respectively. This huge disparity in health-related costs suggests there is untapped potential in EBVs for animals with high IC ratings. Overall, more comprehensive studies to verify these findings, develop EBVs for ICs and gather more comprehensive data on the high IC phenotype is justified.
The original article, Associations between immune competence phenotype and feedlot health and productivity in Angus cattle, can be found on the Journal of Animal Science webpage.