Characterisation of haematological profiles and whole blood relative gene expression levels in Holstein-Friesian and Jersey bull calves undergoing gradual weaning

Abstract

Haematological profiles indicate the health status of an animal and can be used to identify sub-clinical stress responses. The objectives of the study were to examine (i) the effect of breed and plane of nutrition, on haematological profiles of artificially reared Holstein-Friesian and Jersey bull calves in response to gradual weaning, and (ii) the effect of breed on immune response genes in bovine whole blood using real-time quantitative PCR. Holstein-Friesian and Jersey bull calves were group housed indoors and individually fed using an automatic feeder. They were allocated to a high, medium or low plane of nutrition, based on milk replacer (MR) and concentrate. The nutrition treatments were calculated using National Research Council guidelines in order to achieve a high, medium or low growth rate for each respective breed. During the weaning phase MR was gradually reduced over a 14-day (d) period (d −13 to d 0). Calves were blood sampled on d −14, −6, −3, 0, 1, 3, 8 and 14 relative to weaning (d 0) for subsequent haematological analysis. On d −14, 1 and 8, a subset of eight Holstein-Friesian calves randomly selected from the medium nutrition treatment and eight Jersey calves randomly selected from the high nutrition treatment, were blood sampled for gene expression profiling, targeting biomarkers of weaning stress. These two treatment groups were chosen to examine the effect of breed on expression of the genes of interest, as energy intake and animal performance were similar. There was no effect of breed × plane of nutrition interaction nor effect of plane of nutrition on any variable measured ( P > 0.05). Gradual weaning produced differential biological responses in the two breeds evidenced by breed × time interactions for lymphocyte, monocyte and red blood cell number, plasma haemoglobin and haptoglobin concentrations ( P < 0.05). The typical stress response consisting of neutrophilia and lymphopaenia was not observed for any treatment. An immune response to gradual weaning was observed as the relative gene expression level of the pro-apoptotic gene, Fas, increased on d 1 relative to d −14 ( P < 0.05). Relative gene expression levels were greater in Jersey calves compared with Holstein-Friesian for the pro-inflammatory cytokine CXCL8 ( P = 0.05) and the glucocorticoid receptor, GRα ( P < 0.05). The increased levels of these transcripts suggest that Jersey calves may have a more sensitive immune system compared with Holstein-Friesian.

Electronic feeding behavioural data as indicators of health status in dairy calves

“…This is probably because all calves received adequate nutrition (i.e., more than maintenance). This study and our previous study (Johnston et al, 2016a) have demonstrated that feeding greater amounts of MR and Interactions: HS ´ N is an interaction between "health score (HS)" and "plane of nutrition (N)"; HS ´ B is an interaction between "health score (HS)" and "breed (B)"; N ´ B is an interaction between "plane of nutrition (N)" and "breed (B)".…”

“…This experiment was conducted as part of a larger study, and therefore, the animal model and management have previously been described by Johnston et al (2016a). For clarity, it is also briefly outlined here.…”

“…Furthermore, many BRD cases can go undetected, and a study has reported that 69.5% of calves presenting with lung lesions at slaughter had never been treated for BRD (Thompson et al, 2006). As the average daily live-weight gain for calves from each feeding treatment was not compromised (Johnston et al, 2016a), the incidents of BRD detected using on-farm BRDC screening did not appear to have adversely affected growth. Therefore, it is possible that these calves would not be identified as BRD cases without thorough on-farm screening.…”

Effect of breed, plane of nutrition and age on growth, scrotal development, metabolite concentrations and on systemic gonadotropin and testosterone concentrations following a GnRH challenge in young dairy bulls

“…The health status of these animals from initiation of dietary treatments until 14 days post-weaning has been characterized in detail [24].…”

Editorial: Precision livestock farming: a ‘per animal’ approach using advanced monitoring technologies

“…Another approach for automatic lameness detection, gait behaviour and ground reaction forces, is proposed by van Nuffel et al (2016). IR-thermography-based monitoring of body temperature of calves (Hoffmann et al, 2016) and gene expression of calves undergoing gradual weaning (Johnston et al, 2016) are presented in this special issue.…”