Dr Ajmal Khan, Senior Scientist for Ruminant Nutrition at AgResearch, New Zealand, believes that the importance of both early life nutrition and the weaning transition for calves have been overlooked in the past, in terms of how vital they are for promoting the overall well-being and eventual lifetime performance of heifers. He feels that the effects of early life nutrition and the weaning process were not fully recognised until recently because restricted milk feeding and early weaning were considered more economical. Dr Khan explains that scientific work over the last decade has clearly shown that nutrition, weaning processes and management decisions in early life are not only important for calf welfare and survival, but could also potentially affect their long-term performance.
The smoothness of the weaning process is critical, according to Dr Khan. Abruptly cutting calves off from milk supplies stops the smooth development of the rumen and can have a detrimental effect on the health and performance of young calves. Additionally, as calves are born with non-functional rumens, they rely on milk to meet their nutrient demands for both maintenance and growth. Dr Khan stresses that abruptly shifting calves from milk to solid feed, or doing so too soon, puts calves at risk for poor growth and performance, post weaning.
Dr Khan points out that the long-term performance of heifers in commercial herds is potentially linked to neonatal feeding and rearing systems. Furthermore, rearing animals with greater long-term performance and resiliency is vitally needed if the future of food production is to be sustainable. Indeed, research is already well underway in many institutions to assess the effects of early life nutrition and management practices on the long-term performance and health of heifers.