Animal scientists will spend hours at conferences arguing whether to draw a straight or a curved or a broken line through their data points. The shape of the line really matters because it impacts on profit. It tells us how our diets might need improving (cost) and the growth we can expect (value).
There is a well-established conventional curve that shows how pigs grow. However, there is now also a new accelerated growth curve for pigs that tells a different lifetime performance story for pigs that have been offered an accelerator from day 4 to weaning.
CONVENTIONAL CURVE: BETTER START - BETTER FINISH
Feeding a better diet to enhance weaning weight or nursery exit weight is known to advance the piglet up the conventional curve to give around a 3:1 weight benefit by slaughter (0.2kg at weaning gives 0.6kg at slaughter or 0.5kg nursery exit weight gives 1.5kg at slaughter – ROI of also around 3:1). Pigs fed a better diet improve their early growth and ‘jump up’ the same curve so they are heavier if slaughtered at the same age or younger if slaughtered at the same weight. This is all about early extra nutrients to give extra growth. We are all familiar with this curve as pig producers and have observed it for many years.
ACCELERATORS. A TRANSFORMATIONAL GROWTH CURVE
When offered up to weaning, Accelerators affect the pig’s metabolism in a way that does little or nothing to growth pre-weaning. Pigs do not follow the ‘higher up the same curve’ pattern seen with improved conventional diets because the accelerated growth benefit kicks in after weaning and on similar nutrient intakes from unchanged post weaning diets. The pig utilises nutrients for growth more efficiently and is placed on a new and different curve by its improved metabolism and lower immune activity.
This is all about efficiency, about how nutrient intake is used more effectively and not about increased nutrient intake. In university and farm trials an extra 4 and 5kg at slaughter has been delivered from zero improvement in weight at weaning without changing any post weaning diets (delivering a credible ROI of 5:1). As such, the transformational growth curve is seen on standard diets fed from weaning onwards. With Accelerators, the pig has been changed, not the diet and this is why the conventional 3:1 rule of thumb no longer applies with Accelerators, in fact trials are showing a transformational 4:0 (slaughter:weaning weight improvement).
(Previously published in International Pig Topics)
