FEED Business Worldwide - August 2012
Pre-weaning concentrate's impact on calf performance
by Eilish M LYNCH1,2, Mark McGEE3, Sean DOYLE2 and Bernadette EARLEY1*
1 Animal and Bioscience Research Department, Animal & Grassland Research and Innovation Centre, Teagasc, Grange, Dunsany, Co. Meath, Ireland
2 Department of Biology and National Institute for Cellular Biotechnology, National University of Ireland Maynooth, Co. Kildare, Ireland
3 Livestock Systems Research Department, Animal & Grassland Research and Innovation Centre, Teagasc, Grange, Dunsany, Co. Meath, Ireland
Within seasonal, grassland-based suckler beef production systems in Ireland, calves are generally springborn and reared with their dam at pasture for approximately 8 months until the end of the grazing season in autumn when they are weaned. At, or, shortly after weaning, calves are housed indoors over the winter period and offered grass silage, which is generally supplemented with concentrates. Concentrate supplementation of suckling, grazing beef calves prior to weaning is commonly referred to as 'creep feeding', and serves to compensate for decreasing milk yield and forage, and to improve calf weaning weights.
Additionally, this practice is often advocated as a means of reducing weaning stress in calves through the familiarisation to a palatable feed, such as concentrates and has been reported to decrease morbidity in feedlots.
Weaning is a stressful event in the calf's lifetime with alterations in behaviour, hormonal mediators of stress and immune function evident post-weaning. Deferring housing at the time of weaning results in a less marked stress response compared with the traditional practice of weaning and simultaneous housing. Previous studies have also examined the effects of pre-weaning concentrates on measures of post-weaning physiological and immunological responses. Abrupt weaning coupled with housing causes transitory neutrophilia, mediated by reduced surface expression of L-selectin, and transient lymphopaenia, characterised by decreased percentage CD4+, CD8+ and WC1+ lymphocytes and increased MHC class II+ cells. Although, some studies have examined the effects of pre-weaning calf management, such as two-stage weaning with nose-clips, on the stress response of beef calves post-weaning.
Thus, the objectives of the study were to examine the effects of offering concentrate supplementation to beef calves (CS) for 26 days prior to abrupt weaning and housing on (i) peripheral distribution of leukocytes, (ii) functional activities of neutrophils, and (iii) acute phase protein response compared with calves that were not offered concentrate supplementation (NCS) prior to weaning. The metabolic and behavioural responses of calves were also characterised to provide supplementary information.
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