The change in differing leukocyte populations during vaccination to bovine respiratory disease and their correlations with lung scores, health records, and average daily gain1,2,3

Abstract

Bovine respiratory disease (BRD) is the most economically important disease in U.S. feedlots. Infection can result in morbidity, mortality, and reduced average daily gain. Cheap and reliable genetic methods of prediction and protection from BRD would be highly advantageous to the industry. The immune response may correlate with BRD incidence. Cattle (n = 2,182) were vaccinated against common viral and bacterial pathogens of BRD. Two blood samples were collected, one during booster vaccination and one 21d later, enabling 3 phenotypes for each trait [prebooster (pre), postbooster (post), and delta (post minus pre)]. From the blood samples innate and adaptive responses [counts of white blood cells (WBC), neutrophils, lymphocytes, monocytes, eosinophils, and basophils] were measured. In addition, feedlot ADG and binary traits [health records (HR; 0 = healthy, 1 = ill) and lung scores (LS; collected at harvest; 0 = no lesions, 1 = lesions)] were also recorded. Traits ADG, HR, and LS have all been significantly correlated with infection to BRD. In this investigation we aimed to find correlations between the immune response and ADG, HR, and LS to find an easily measurable trait that would be a good predictor of BRD resistance after vaccination. The results showed an average positive delta for the innate immune response (eosinophils, basophils, neutrophils), whereas the adaptive immune response had an average negative delta (lymphocytes). Overall, we discovered that the immune responses had moderately high heritabilities (h(2); lowest: delta monocytes, 0.21 ± 0.05; greatest: pre lymphocytes: 0.5 ± 0.05), with lymphocytes having the greatest h(2) throughout the study (h(2) ≥ 0.41). All genetic correlations were calculated using bivariate REML models. Although LS did not significantly correlate with any of the immune phenotypes, both ADG (post lymphocytes, -0.24 ± 0.12) and HR (pre eosinophils, -0.67 ± 0.29; delta WBC, -0.5 ± 0.24, and delta lymphocytes, -0.67 ± 0.21) did. All the significant genetic correlations with HR were negative; resistance to BRD appears to be a function of greater delta lymphocytes and WBC. The increase in eosinophils may potentially link its role in decreasing lymphocytes. These results may enable producers to predict if revaccination, quarantine, and breeding of animals is required to reduce the incidence of BRD postvaccination. In addition, immunological phenotypes maybe used to aid genomic selection indices to select animals with greater rates of protection after BRD vaccination.

Complete blood count data and leukocyte expression of cytokine genes and cytokine receptor genes associated with bovine respiratory disease in calves

“…The average, minimum and maximum values for the whole blood parameters are reported for all animals at pre-conditioning (n = 796) and at weaning (n = 791) in Table 1 . Most of the average values obtained fell within the reference intervals of at least one of three bovine studies presented in Roland et al [ 6 ] and Leach et al [ 1 ]. All values fell within the reference intervals provided by hematologic reference chart in the Merck Veterinary Manual.…”

“…Calves were all born and raised at USMARC at three locations with no fenceline contact. At pre-conditioning (~ 120 days of age), which is preweaning vaccination with Bovi Shield Gold One Shot (Zoetis) and Vision 8 with SPUR (Merck, USA) and at weaning (~ 150 days) with the vaccination Bovi Shield Gold One Shot, blood was collected as previously described [ 1 ]. Briefly, whole blood was collected into tubes containing liquid EDTA as an anticoagulant for a complete blood count (CBC) from 796 animals at pre-conditioning and 791 animals at weaning, when calves were relocated from pasture to a feedlot.…”

“…Previously, Leach et al [ 1 ] described relationships between changes in WBC and lymphocytes in response to vaccine and health records in calves. White blood cells use small pro- and anti-inflammatory cytokines as molecular signaling mechanisms to communicate with each other.…”

The monster we don't see: subclinical BRD in beef cattle

“…It has become cliché to note that ‘Bovine Respiratory Disease (BRD) is the most expensive disease of cattle in the United States (US)’. Estimates always include the cost of sickness treatments, deaths, and loss of performance (Smith, 1998; Epperson, 1999; Irsik, 2010; Leach et al , 2013). Almost all discussion and estimates of loss revolve around calves, especially stressed calves immediately post-weaning.…”

<b>Influência etária na resposta imunológica de bezerros à vacinação intranasal</b>

“…As barreiras físicas são aquelas que impedem a penetração dos microrganismos invasores e são imprescindíveis para a proteção bem sucedida. No trato respiratório, os mecanismos de defesas físicas incluem os processos de "autolimpeza", como tosse, espirro e o fluxo de muco no trato respiratório (LEACH et al, 2013;TIZARD, 2014).…”