University of Alberta, Canada
Dr Michael Steele was born and raised on a Holstein dairy farm in southwest Ontario. After completing a Masters in Animal Nutrition at the University of Guelph in 2003, Steele worked for a year as a consultant in the Chinese dairy industry, and then two years as the head dairy nutritionist for Masterfeeds in Canada. Steele then returned to academics and completed a PhD that focussed on characterising how the rumen epithelium adapts during grain-induced ruminal acidosis in cattle for three years followed by a one year post-doctoral fellowship; all with Dr Brian McBride at the University of Guelph (2007-2012). Through the course of his PhD he established productive research collaborations with professors throughout Canada, USA, New Zealand and Europe resulting in over 20 peer-reviewed publications.
After his postdoctoral fellowship, Steele worked for Nutreco Canada Agresearch as research scientist for two years, where he supervised undergraduate and graduate students and conducted research in the field of gastrointestinal health and function of the calf and lactating dairy cow. In 2014, he took up his current position at the University of Alberta, where he supervises undergraduate, MSc, PhD, postdoctoral fellows and research technicians. Over the last five years, he has published 28 peer-reviewed publications, 31 conference publications and has given 34 presentations to scientists, industry and producers.
Nutritional Regulation of Gastrointestinal Development
Dr Michael Steele of the University of Alberta, Canada, spoke during the morning session on the second day of the international symposium that marked the official opening of Trouw Nutrition's new Calf & Beef Research Facility in April, 2016.
His presentation focused on the nutritional regulation of gastrointestinal development of rearing calves and included a discussion of trends in calf management as well as a thorough examination of the pre-weaning period, including both immediate neonatal needs and the effects of elevated feeding planes through the first few months of life.
He went on to share an in-depth analysis of best practices and strategies in weaning, and concluded with a brief but important look at post weaning feed efficiency. Ultimately, Dr Steele's desire is to integrate both the pre and post-weaning planes of nutrition, to assist in creating seamless gastrointestinal development and encourage greater lifetime performance.
Calf management trends
Dr Steele began his presentation by outlining several general trends in calf management. He emphasized that in early life, especially during the pre-weaning phase, calves are quite efficient, and that even though the cost of feeding can be high, early dietary regimes strongly influence lifetime milk production. On the other hand, he touched upon how antibiotic overuse can and does have an adverse impact on lifetime milk production. Dr Steele also discussed that high mortality rates during the pre-weaning period, mostly due to scours and other gut health issues, mean that we must address the link between neonatal nutrition and gut health, to decrease morbidity and mortality.
Pre-weaning nutrition and gastrointestinal development
A great deal of gastrointestinal development happens prenatally. Even so, says Dr Steele, immediately after birth there is rapid microbial colonization of the rumen. Therefore, how a calf is fed in the first few hours of life can have a tremendous impact on microbiota and gut function. Colostrum, therefore, is essential in so many ways. Yes, passive transfer of IgG is indeed important.
But, as Dr Steele makes clear, there are other components in colostrum such as prebiotics, probiotics and other bioactives that should also factor into the colostrum equation. Therefore, Dr Steele makes clear that it is not a good idea to only feed colostrum in the first meal (or from the first milking), but to continue to feed it through the first week of a calf's life while transitioning to whole milk or CMR. Doing so, especially when heat-treated, says Dr Steele, can have significant long-term positive impact on gut health and overall lifetime performance.
In terms of feeding plane, the pre-weaned calf has tremendous capacity. In fact, they can consume 12 litres per day at day 4! Therefore, as Dr Steele notes, it is not a good idea to restrict calves, even in the first week, especially since research shows that calves that consume more milk have better health and growth throughout the pre-weaning phase. While feeding larger meals 2 times per day can increase the risk of milk overflow into the rumen which could negatively influence the gut, Dr Steele explained that calves have an amazing ability to adapt as evinced by slower abomasal emptying with larger meal size. Therefore, elevated planes of nutrition can (and should) be fed early in life!
As the rumen grows tremendously during weaning, it is important to remember that weaning includes quite a transition in gut function and metabolism. As research shows that when feeding high planes of nutrition, early and abrupt weaning can impact performance, Dr Steele advises later weaning with a smoother, step-down method. He explained that a smoother transition increases gain and decreases morbidity and mortality. While in nature calves would drink milk for up to 8 months and so in the dairy industry it is always early and abrupt by comparison, Dr Steele pointed to research by Eckert et al. (2015) which clearly showed that weaning at 8 weeks is more advantageous for gut function than at 6 weeks and to his own research, also from 2015, which shows that gradual, step-down weaning is better than abrupt weaning. He posited that decreasing total meal size may be better than simply eliminating a meal for gradual weaning.
Metabolizable energy intake
As there is an enormous shift in dry matter intake in just a couple of days with the weaning transition, Dr Steele indicated that calves simply aren't ready to consume the greater amounts of starter (they shift from 500g to 2000g per day). While step-down is better, he notes that there is still much left to learn and understand. His own research shows that calves have bigger forestomachs and more rumen fill with step-down weaning, but that there's little difference in the papillae as calves adapt very quickly, post weaning. While the emphasis has been on ADG during the weaning period, Dr Steele believes that more needs to be studied in terms of gut function as it, too, is changing quite a bit!
Post weaning nutrition
Dr Steele feels that more also needs to be studied in terms of post weaning nutrition. He explained that feed efficiency can be quite high and that after weaning calves also have enormous capacity. Therefore, by restricting the post weaned calf, he believes that we are not maximizing their potential. He emphasized that the dairy industry has a huge opportunity to take advantage of feed efficiency post weaning, and that we should therefore integrate the pre-weaning plane of nutrition with the post weaning plane of nutrition to optimize growth, health and production.