Browsing Animal & Grassland Research & Innovation Programme by Subject "Weaning"
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Characterisation of physiological and immunological responses in beef cows to abrupt weaning and subsequent housingBackground: Weaning involves the permanent separation of the calf from the dam and has been shown to be stressful for both. The objectives of this study were to characterise the effect of i) abrupt weaning and ii) subsequent housing on the extended physiological and immunological responses of beef cows. At weaning (day (d) 0, mean age of calf (s.d.) 212 (24.5) d), cows were abruptly separated from their calves and returned to the grazing area. After 35 d at pasture, cows were housed in a slatted floor shed and offered grass silage ad libitum plus a mineral-vitamin supplement daily. Rectal body temperature was recorded and blood samples were obtained on i) d 0 (weaning), 2, 7, 14, 21, 28, 35 and subsequently on ii) d 0 (housing), 2, 7, 14 and 21 for physiological, haematological and immunological measurements. Results: Post-weaning, concentration of cortisol and dehydroepiandrosterone were unchanged (P > 0.05). Rectal body temperature, neutrophil number and neutrophil: lymphocyte ratio increased (P < 0.01) on d 2 compared with pre-weaning baseline. Lymphocyte and neutrophil number decreased (P < 0.05) on d 2 to 7 and d 7 to 21, respectively, compared with pre-weaning baseline. Interferon-γ production decreased (P < 0.05) on d 2 compared with pre-weaning baseline. An increase (P < 0.05) in acute phase proteins, fibrinogen and haptoglobin was evident on d 2 to 35 compared with pre-weaning baseline. Concentration of glucose increased on d 2 to 28, whereas non-esterified fatty acid decreased on d 2 to 35 compared with pre-weaning baseline. Post-housing, concentrations of cortisol, rectal body temperature, total leukocyte number, and glucose were unchanged (P > 0.05). On d 2 post-housing, neutrophil number and neutrophil: lymphocyte ratio increased (P < 0.05), whereas lymphocyte number and concentrations of dehydroepiandrosterone, fibrinogen and non-esterified fatty acid decreased (P < 0.05) compared with pre-housing baseline. Concentration of haptoglobin increased (P < 0.05) on d 14 to 21 post-housing. Conclusions: A transitory increase in neutrophil number and decrease in lymphocyte number, increased neutrophil:lymphocyte ratio coupled with decreased interferon-γ production, and increased concentration of acute phase proteins indicate a stress response in cows post-weaning, whereas post-housing, changes were less marked.
Characterisation of the Whole Blood mRNA Transcriptome in Holstein-Friesian and Jersey Calves in Response to Gradual WeaningWeaning of dairy calves is an early life husbandry management practice which involves the changeover from a liquid to a solid feed based diet. The objectives of the study were to use RNA-seq technology to examine the effect of (i) breed and (ii) gradual weaning, on the whole blood mRNA transcriptome of artificially reared Holstein-Friesian and Jersey calves. The calves were gradually weaned over 14 days (day (d) -13 to d 0) and mRNA transcription was examined one day before gradual weaning was initiated (d -14), one day after weaning (d 1), and 8 days after weaning (d 8). On d -14, 550 genes were differentially expressed between Holstein-Friesian and Jersey calves, while there were 490 differentially expressed genes (DEG) identified on d 1, and 411 DEG detected eight days after weaning (P < 0.05; FDR < 0.1). No genes were differentially expressed within breed, in response to gradual weaning (P > 0.05). The pathways, gene ontology terms, and biological functions consistently over-represented among the DEG between Holstein-Friesian and Jersey were associated with the immune response and immune cell signalling, specifically chemotaxis. Decreased transcription of several cytokines, chemokines, immunoglobulin-like genes, phagocytosis-promoting receptors and g-protein coupled receptors suggests decreased monocyte, natural killer cell, and T lymphocyte, chemotaxis and activation in Jersey compared to Holstein-Friesian calves. Knowledge of breed-specific immune responses could facilitate health management practices better tailored towards specific disease sensitivities of Holstein-Friesian and Jersey calves. Gradual weaning did not compromise the welfare of artificially-reared dairy calves, evidenced by the lack of alterations in the expression of any genes in response to gradual weaning.
Effect of post-weaning management practices on physiological and immunological responses of weaned beef calvesThe objectives were: i) to investigate the physiological and immunological responses of previously grazed, abruptly weaned beef calves that were then either housed (H) and offered a diet of grass silage ad libitum plus concentrate or returned to familiar pasture (P) (Phase I), and ii) to examine the effect of subsequent housing (35 days post-weaning) on these responses in P calves compared with the H calves, which were acclimated to housing (Phase II). Rectal temperature was recorded and jugular blood was collected on days 0 (weaning), 2, 7, 14, 21, 28 and 35 (Phase I) and on days 0 (housing of P), 2, 7, 14, and 21 (Phase II). There was a treatment × sampling time interaction (P<0.05) for rectal temperature, fibrinogen concentration, total leukocyte and lymphocyte number, and phytohaemagglutinin-induced interferon-γ production during Phase I, with H calves having higher (P<0.05) rectal temperature and fibrinogen concentrations on day 7, lower total leukocyte and lymphocyte number on days 7 to 35 and days 2 to 28, respectively, and reduced interferon-γ production on day 7 compared with P calves. Neutrophilia (P<0.05) was present in P calves on days 2 and 7 post-weaning. In Phase II, total leukocyte and neutrophil numbers increased (P<0.05), whereas lymphocyte number declined on day 2 relative to values on day 0 of Phase II. In conclusion, deferring housing at the time of weaning resulted in a less marked stress response in beef calves compared with the traditional combined practice of weaning and simultaneous housing, however these changes were minimal suggesting that the overall health and welfare of beef calves was not compromised by abrupt weaning and simultaneous housing.