Complete blood count analysis on beef cattle exposed to fescue toxicity and rumen-protected niacin supplementation

Gaston F. Alfaro, Sandra L. Rodriguez-Zas, Bruce R. Southey, Russell B. Muntifering, Soren P. Rodning, Wilmer J. Pacheco, Sonia J. Moisá

Research output: Contribution to journalArticlepeer-review


Offspring born to dams genetically tested for resistance to fescue toxicity were separated in groups based on their dams’ resistance level (tolerant vs. susceptible). Rumen-protected niacin (RPN) is proposed as a potential alleviator for vasoconstriction produced by fescue toxicity. Complete blood count (CBC) analysis was utilized for detection of significant responses to treatments applied. Our objectives were as follows: (a) to analyze changes in CBC due to fescue toxicity, maternal resistance level, and RPN in growing offspring; and (b) to assess the effects of maternal resistance level when consuming endophyte-infected tall fescue seeds in addition to RPN in offspring performance. Body weight, average daily gain, or health status were not improved by RPN or the genetic test to detect fescue toxicity resistance. Typical signs of alkaloids intoxication and heat stress were noticed in offspring. Particularly, rectal temperature was greater for susceptible control heifers. Results showed that susceptible control offspring presented signs of anemia denoted by low mean corpuscular hemoglobin (MCH) and mean corpuscular volume (MCV). High levels of white blood cells (WBC) and basophils in combination to low neutrophils to lymphocytes ratio were the signs of infection or inflammation detected in the CBC analysis, especially in tolerant niacin steers. Furthermore, offspring of control heifers had a greater percentage of reticulocytes and RDW, denoting signs of anemia.

Original languageEnglish (US)
Article number988
Issue number4
StatePublished - Apr 2021


  • Animal performance
  • Beef cattle
  • Complete blood counts
  • Ergovaline
  • Fescue toxicity
  • Fetal programming
  • Genetic test
  • Heat stress
  • Rumen-protected niacin
  • Tolerance index

ASJC Scopus subject areas

  • Animal Science and Zoology
  • veterinary(all)


Dive into the research topics of 'Complete blood count analysis on beef cattle exposed to fescue toxicity and rumen-protected niacin supplementation'. Together they form a unique fingerprint.

Cite this